CC-130 Hercules Aircraft Power Distribution System€¦ · CC-130 Hercules Aircraft Power...
178
Power Quality Analysis CC-130 Hercules Aircraft Power Distribution System J. C. Cartier, CD, BESc., Captain Canadian Forces Department of Electrical and Cornputer Engineering Royal Military College of Canada Kingston, Ontario
Transcript of CC-130 Hercules Aircraft Power Distribution System€¦ · CC-130 Hercules Aircraft Power...
Power Quality Analysis
CC-130 Hercules Aircraft Power Distribution System
J. C. Cartier, CD, BESc., Captain
Canadian Forces
Department of Electrical and Cornputer Engineering
Royal Military College of Canada
Kingston, Ontario
National Library m * l of Canada Bibliothèque nationale du Canada
Acquisitions and Acquisitions et Bibliographic Services services bibliographiques
395 Wellington Street 395, rue Wellington CXhwaON K1AOM Ottawa ON K 1 A O N 4 Canada Canada
The author has granted a non- exclusive Licence dowing the National Library of Canada to reproduce, loan, distribute or sel1 copies of this thesis in microform, paper or electronic formats.
The author retains ownership of the copyright in this thesis. Neither the thesis nor substantial extracts hm it may be printed or otherwise reproduced without the author's permission.
L'auteur a accordé une licence non exclusive permettant a la Bibliothèque nationale du Canada de reproduire, prêter, distribuer ou vendre des copies de cette thèse sous la forme de microfiche/fih, de reproduction sur papier ou sur format électronique.
L'auteur conserve la propriété du droit d'auteur qui protège cette thèse. Ni la thèse ni des extraits substanîiels de celle-ci ne doivent être imprimés ou autrement reproduits sans son autorisation.
Power Quality Analysis in a
CC-130 Hercules Aircraft Power Distribution System
by
J. C. Cartier, CD, BESc.,
A Thesis Presented to the School of Graduate Studies
in the Department of Electrical and Computer Engineering Royal Military College of Canada
Kingston, Ontario
In partial fuffiiiment of the requirements for the degree
Master of Engineering January 1999
0 Copyright by I.C. Cartier, 1999
"This thesis may be used within the Deparûnent of National Defence but copyright for open publication remains the property of the author."
Keywords
Avio nics
Distortion
Hannonics
~ i c r o ~ r a n @
Nonlinear Loads
Waveform Distortion
Overvoltage Transients
Power Quality Analysis
Transformer Rectifier Unit
Aircraft Electricai Distribution System
Dedication
To my supportive wife Karen, rny son Christopher and my
daughter Nicole
Abstract
Power system studies can provide useful information on the performance of existing or fùture systems during normal or abnormal operathg conditions. Harmonies and overvokage transients are two major system characteristics, which can significantly influence systern performance. The sources of these undesirable characteristics are many and varied, including transformers, switching tmsients, nonlinear loads, and devices such as the static power converter. The future use of nonlinear loads is expected to increase since these loads are generally highiy efficient. Unfortunately, as the use of these loads increase, waveform distortion is expected to rise. This rise will certainiy infiuence overall system performance unless adequate measures are adapted to control and maintain power quality.
Future advanced aircrafi avionics systems will require reliable, redundant, and unintemptable elecûical power to supply flight and mission critical loads. The Canadian Forces CC430 Hercules aircraft fleet is scheduled for an avionics update which will include sophisticated sensitive avionics equipment. The power quality required for this update may not be adequate since the existing electrical distribution system was designed to satisfy load requirernents of the 1950's.
This thesis describes the use of ~icrotran '~, a transients analysis simulation program, and the development of a laboratory mode1 to predict the CC-130 Hercules aircrdt electricai switching transients and steady-state response, including voltage and current harmonic levels on the power distribution system using tabuiated equiprnent load data. The simulation and laboratory results are then compared for validation with field measurement data.
Acknowledgments
I would like to express rny sincere appreciation and thanks to my thesis advisor Dr. A.Y. ChiWiani and CO-advisor Dr. G. Ferland for their assistance and guidance during this endeavour,
This work could not have been completed without the assistance and support of John Cheng and his staff h m the Naval Engineering Test Establishment (NETE), Lasalle, Québec, who provided the instrumentation and produced over five hundred wavefom and spectral density plots.
1 would also like to acknowledge the efforts of Mrs. Nancy Tmkington of RMC Science and Engineering Library who provided quick access to the required technical publications.
Vit a
Jean Calixte Cartier
Place and Yeu of Birth:
Education:
Chatham, Ontario, 1 953
Ontario Prirnary and Secondary Schools; Completed Grade 12 in 1971.
St Clair College, Windsor, Ontario, 1976- 1977.
University of Western Ontario, London, Ontario, 1982- 1986. Awarded BESc (Elec Eng).
Weapons Underwater Technician, Canadian Armed Forces, HMCS Margaree, HMCS Okanagan. Halifax, Nova Scotia, 1971-1976.
Electronic Technician, for K.E.L. Communications and SeMce Eiectrohorne, Windsor, Ontario, 1977- 1979.
Integral Systems Technician, Canadian Forces Base Moose Jaw, Saskatchewan, 1980-1 982.
Aerospace Engineer, Canadian Forces, 1986 to date including:
Avionics Support Onicer and Project Support Officer, Canadian Forces Base Greenwood, Nova Scotia, 1988-1991.
Graduate Student, Royal Miiitary College of Canada, Kingston, Ontario, 1 99 1 -1 993.
Aerospace Engineering Officer, Duectorate Aerospace and Engineering Program Management, National Defence Headquarters, Ottawa, 1993-1998.
Table of Contents . .
Kcywords ....................................................................................................................... il ... ..................................................................................................................... Dedication 111
Abstract ......................................................................................................................... iv .......................................................................................................... Acknowledgments v
Vita ............................................................................................................................... vi
Table of Contents ............................................................. vii ................................................................................................................. List of Figures x
.. t List of Tables .............................................................................................................. uii
...................................................................................................... List of Photognphs xv
............................................................................................................. Nomenclature xvi
Cbapter 1 1.1
1.2
Chipter 2 2.1
Introduction ......................................................................................... 1 General .................................................................................................. 1
.................................... .............**.....*.......*......... Background ............... 3 1.2.1 Harmonies in Distribution Systems ........................................ 3
1.2.2 Electncal Transients in Distribution Systems ....................... .. 5 1.2.3 Aircrafi Elecûical S ystems ...................................................... 8
Thesis Objective .................................................................................... 9
Theory .............................................................................................. I l CC-1 30E Electrical Distribution System ....................... .... .......... II 2.1.1 AC Bus Distribution System ................................................. 14 2.1.2 DC Bus Distribution System ............................................... 15
2.1.3 AC and DC Loading ................. .... ................................ 16
Hannonic Analysis .............................. ........ ................................. 17 2.2.1 Harmonic Distortion O a figure of merit ............................ .... 19
Transformer Rectifier Units ........................... ..... ...... ...,.. .......... 20 .................................................. Modelling the Network's Elements 25
2.4.1 Line Model ........................ ...... ............................................ 25
............................................................ 2.4.2 Reactive Load Mode1 26 ................... . 2.4.3 Generator Mode1 ....... ...................,... 28
vii
Chapter 3 3.1
3.2
Chapter 4 4.1 4.2 4.3
Implementatioa ............................................................................... 29 ................................................................................................ General 29
Developrnent of the System Mode1 ..................................................... 29
3 -2.1 Generator Mode1 ................................,,.................................. 30 ....................*... ........*......*..... 3 .2.2 Distribution Conductors ......... 32
3.2.3 Switching Loads ................................................................. 32 .................................................. 3.2.4 Transformer Rectifier Units 34
.............................. ................... 3.2.5 AC and DC Loading .... 35 QP .............................................................. MicroTran Simulation Tool 37
........................................................... 3.3.1 MicroTran@ Overview 37
3.3.2 ~ i c r o ~ r a n @ Data Input File .................................................. 38 Simulation Mode1 ........................................................................ 39
.......................................................... 3.4.1 Duration of Simulation 42 ......................................................... Micro~ran@ Harmonic Analysis 44
.......................... ............................ AVTRON Laboratory Models ... 45 3.6.1 Essential Branch Mode1 ......................................................... 48
............................................................... 3.6.2 MainBranchMode1 48 .................................................................... Aircrafi Data Acquisition 50
Instrumentation and Measurements .................................................... 52
Evaluation and Validation ............................................................... 60 Introduction ............................,............... .......................................... 60 Data Processing and Reduction ......................................................... 60
Case No . 1: No Loads ........................ .. .............................................. 62 4.3.1 AVTRON Laboratory and Simulation Resuits ..................... 63 Case No . 2: Essential Branch - DC Load .......................................... 66
4.4.1 AVTRON Laboratory and Simulation Resdts ..................... 67
Case No . 3: Essential Branch - AC and DC Loads ............................ 70
4.5.1 AVTRON Laboratory and Simulation Resuits ..................... 71
Case No . 4: Essentid Branch - AC Transient and DC Loads ............ 75 4.6.1 AVTRON Lûboratory and Simulation R e d t s ..................... 76
Case No . 5: Main Branch - AC and DC Loads .............. .......... .......... 79 4.7.1 AVTRON Labonitory and Simulation Resuits ..................... 79 Case No . 6: Main Branch - AC Transient and DC Loads .................. 82
4.8.1 AVTRON Labonitory and Simulation Results ..................... 83
Abcraft Triai Redts .......................................................................... 88
Chapter 5 Conclusion ......................................................................................... 99 Summary of Work ............................................................................... 99
.................................................. Recommendation for Further Work 102
................................................................................................................... References 104
Appendix A Essential and Main Branch Power Consumption Tables ........... A-1
................. Appendix B Derivation of TRU Transformer Mode1 Parameters B-1 B . I Open-Circuit Test .............................. .. ................................ B- 1
.................................... B . 1 .. Transformer tron Losses ..., B-4 B . 1.2 Excitation Test Data ........................................................... B-5 . ............................................*.. B 1.3 Transformer DC Resistance B-5 . ....................................... B 1.4 Transformer Secondary Voltage B-6
B.2 Short-Circuit Test ........................................................................... B-6
................................................. 8.2.1 Short-Circuit Impedance B-8
.................................................. B.2.2 Short-Circuit Resistance B- 10
.........................*........ .......... . B 2.3 Transformer Load Losses .... B- 10
................................................. B.3 TRU Transformer Configuration B- 11
Appendix C
Appendix
Appendix
Appendu
Recording. Reduction. and Support Equipment for AVTRON Laboratory Mode1 and Aircraft Teating ................... C-1
.................................................................... Recording Equipment C- 1
Data Reduction Equipment ............................................ .............. C-2
.......................................................................... Support Equipment C-3
AVTRON Labontory Model and AUcirft Trial Photographs D-l
Aircraft Electrical Load
Simulation Model Input
Checküst
Data FiIe
List of Figures ..................................... Electrical Power Distribution System ... 12
.................................................... AC Generating Control System 13
Figure 2.1 . CC430 Figure 2.2 . P h a r y
l
r
Figure 2.3 . Single Line Generator to AC Bus Distribution System ............................. 14
Figure 2.4 O DC Bus System .......................................................................................... 16
Figure 2.5 . Three-Phase Twelve-Pulse Transformer Rectifier Unit ............................. 21
Figure 2.6 - Six-Phase Forked Y Transformer Comection ...................................... ... 22
.................................................................................... Figure 2.7 - Static Load Models 27 .................... ..................... Figure 3.1 - Single Line Block Diagram of Test Set-Up .. 30
.............................................. Figure 3.2 - Essential and Main Branch Transient Loads 33 ....................... ..................................... Figure 3.3 - AC and DC Branch Static Loads ... 36
..................................................................... Figure 3.4 - AVTRON Laboratory Mode1 47
. ................ Figure 3.5 - Essential AC Bus Current THD Summary for Test Case No 4 55
.................... . Figure 3.6 - Main AC Bus Current THD Sumrnary for Test Case No 6 .. 55
........................ . Figure 3.7 - Essential AC Bus Loading Sumrnary for Test Case No 4 57
. ................ Figure 3.8 - Essentid AC Bus Power Factor Summary for Test Case No 4 57
. .............................. Figure 3.9 - Main AC Bus Loading Summary for Test Case No 6 58
.................... . Figure 3.10 - Main AC Bus Power Factor Summary for Test Case No 6 58
...................... . Figure 3.1 1 - Essentid DC Bus Loading Summary for Test Case No 4 59
. ............................ Figure 3.12 - Main DC Bus Loading Summary for Test Case No 6 59
Figure 4.1 . Case 1 : VA & k Waveforms
Figure 4.2 . Case 1: IA Hannonic Profile
Figure 4.3 . Case 1 : VA & IA Waveforms Figure 4.4 . Case 1: IA Hannonic Profile Figure 4.5 . Case 1 : VA & IA Waveforms Figure 4.6 . Case 1: IA Harmonic Profile
Figure 4.7 . Case 2: VA & IA Waveforms
...................................................................... 65
.................................................................... 65
......................... "5% TRU Transformer 1.. 66
"5% TRU Transformer 1.. ......................... 66
"AVTRON Laboratory Model" .................. 66
................... "AVTRON Laboratory Model" 66
..................... Figure 4.8 O Case 2: VA Harmonic Profile .. ....................................... 68
Figure 4.9 O Case 2: Ia Hamionic Profile .................................................................. 68
Figure 4.10 O Case 2: VA & IA Waveforms "AVTRON Laboratory Model" ................ 69
Figure 4.1 1 w Case 2: VA Hiwionic Profile "AVTRON Laboratory Model" ............... 69 ................. Figure 4.12 O Case 2: IA Hamionic Profile "AVTRON Laboratory Model" 69
.............................................................................. Figure 4.13 O Case 3 : VA Waveform 72 ............................. ................... Figure 4.14 O Case 3 : VA Harmonic Profile ..... .. 72
.............................................................................. Figure 4.1 5 O Case 3: Ve Waveform 73
Figure 4.1 6 . Case 3 : VB Hannonic Profile ..................... ..... ................................... 73 Figure 4.17 . Case 3 : VC Wavefonn .............................................................................. 73 Figure 4.1 8 O Case 3 : VC Harmonic Profile ................................................................... 73 Figure 4.19 O Case 3: IA Wavefonn ............................................................................ 73 Figure 4.20 O Case 3: IA Hmonic Profile ................................................................... 73
....... Figure 4.2 1 O Case 3: IB Waveform .................................... .... 74 Figure 4.22 . Case 3 : IB Harrnonic Profile ................................................................. 74 Figure 4.23 . Case 3: Ic Wavefonn .............................................................................. 74 Figure 4.24 O Case 3: Ic Harmonic Profile ................................................................. 74 Figure 4.25 . Case 3: VA & IA Wavefonns "AVTRON Laboratory Model" ................ 74 Figure 4.26 . Case 3: VA Harmonic Profile "AVTRON Laboratory Model" ............... 75
Figure 4.27 O Case 3: IA Harmonic Profile " AVTRON Laboratory Model" ................. 75 Figure 4.28 . Case 4: VA & [A Wavefonns .................................................................. 77 Figure 4.29 O Case 4: VA Hannonic Profile ............................................................. 78
.................................................................... Figure 4.30 O Case 4: IA Hamionic Profile 78 Figure 4.3 1 . Case 4: VA Wavefom & Harmonic Profile ........................................... 78 Figure 4.32 O Case 4: IA Waveform & Harmonic Profile ............................................. 78 Figure 4.33 O Phase A Voltage Harmonic Summary for Test Case No . 4 ..................... 78 Figure 4.34 . Case 5: VA & IA Waveforms .............................................................. 80 Figure 4.35 O Case 5: VA Harmonie Profile ............................................................. 81
..................................................................... Figure 4.36 a Case 5: IA Harmonic Profile 81 ................ . Figure 4.37 Case 5: VA & IA Wavefoms "AVTRON Laboratory Model" 81 ............... . Figure 4.38 Case 5: VA HBrrnOnic Profile "AVTRON Laboratory Model" 82
................. . Figure 4.39 Case 5: IA Harmonic Profile " AVTRON Laboratory Model" 82 .............................. ............................. . Figure 4.40 Case 6: VA & IA Wavefom .. 84
............................................................... . Figure 4.41 Case 6: VA Harmonic Profile 84 .................................................................... . Figure 4.42 Case 6: IA Harmonic Profile 84
Figure 4.43 . Case 6: VA Waveform & Harmonic Profile " AVTRON Laboratory Mode1 " .............................................. 85
Figure 4.44 . Case 6: k Waveform & Hamonic Profile " AVTRON Lahra tory Model" ................................................. 85
. ..................... . Figure 4.45 Phase A Voltage Hannonic Siunmary for Test Case No 6 86
....................... . .................*.... Figure 4.46 Case 6: VA Cascade Harmonic Profiie .. 87
....................... ..................... . Figure 4.47 Case 6: IA Cascade Harmonic Profile ... 87 ................................... . Figure 4.48 Load Unbalance Limits for Three-Phase Systems 90
Figure 4.49 . Essential AC Bus Unbalanced Loading Summary for Test Case No . 4 .. 9 1
Figure 4.50 O Main AC Bus Unbalanced Loading Surnmary for Test Case No . 6 ........ 91
Figure 4.5 1 . Case 5: Main AC Bus . IB Waveform & Harmonic Profile " A i r d Trial" .......................... .. ............................................ 92
Figure 4.52 . Case 6: Main AC Bus . IAWavefom & Harmonic Profile .................................. " Aircraft Trial: Search Radar S witch-On" 93
Figure 4.53 . Case 2: Essential DC Bus . T'RU DC Voltage & Harmonic Profile ............................................................................ "Aircraft Trial" 94
Figure 4.54 . Case 2: Essential DC Bus . TRU 1 DC Cunent & Harmonic Profile "Aircrafl Trial" ............................................................................ 95
Figure 4.55 . Case 2: Essential DC Bus . TRU 2 DC Current & Hamionic Profile ........................................... " Aircrafl Trial" ......................... ........ 96
Figure 4.56 . Case 4: Essential DC Bus: T'RU DC Voltage & No . 1 and 2 Current Wavefoms, " Aircrdt Trial: HF Radio Transmit Mode" ............ 98
................................. Figure B . 1 O Y-Y Open-Circuit Test "Two Wattmeter Method" B- 1
.................................. Figure B.2 . A-Y Open-Circuit Test "Two Wattmeter Method" B-2 ............................... Figure B.3 . Y-Y Short-Circuit Test "Two Watûneter Method" 8-7
Figure B.4 . A-Y Short-Circuit Test "Two Wattmeter Method" ................................. 8-7
Figure B S O Transfomer Equivalent Circuit for Short-Circuit Test ........................... B-8 Figure B.6 . TRU Transformer Connection Configuration ....................................... B- 1 1
xii
List of Tables
Table 2.1 O AC Generator to AC Bus Comection Matrix ............................................. 15 Table 2.2 - Realistic Values of Harrnonic Currents Generated by a
............................................................................... Twelve-Pulse Converter 25 Table 2.3 - Copper Conductor Characteristics at 60 and 400 Hz .................................. 26
Table 2.4 . Generator Parameters ..................................... ,,. .................................... 28
Table 3.1 - Generator Rating and Parameters Values .............................. .. .............. 31 Table 3.2 O Simulation Mode1 AC and DC Load Parameters .......................................... 40
Table 3.3 - Summary of TRU Transformer Test Parameters ......................................... 41 Table 3.4 - Mode1 Load Configuration and Test Cases ................................................. 41
Table 3.5 - Simulation Mode1 Steady-State and Transient Data ................................... 43
Table 3.6 - Simulation Mode1 Total Harmonic Distortion (THD %) ............................ 44
Table 3.7 - AC and DC Theoreticai Mode1 Load Parmeters ........................................ 46
Table 3.8 - AVTRON Laboratory Mode1 Steady-State and Transient Data .................. 49
Table 3.9 - AVTRON Laboratory Mode1 Tota! Hannonic Distortion (THD %) .......... 50
...................................................... Table 3.10 - Aircraft Trial Conf~guration Summary 51
Table 3.1 1 - A i r c d Essential a d Main Branch Steady-State and Transient Data ...... 53 Table 3.12 - A i r c d Trial Total Hannonic Distortion (THD %) ................................. 54
Table 3.13 - Essential and Main Bus Loading Summary for Test Case No . 4
and No . 6 Scenarios .............................................................................. 56
Table 4.1 - A i r c d Essential AC Bus Load Profile ....................... .... ...................... 90
Table A . 1 - Tabuiation of AC Power Consumption .................................... .... .......... A 4
Table A.2 - Tabulation of DC Power Consumption .................................... .... . . . . A 4
Table A.3 - Essential AC Bus Power Consumption during Taxi Condition .............. A-2
Table A.4 - Essential AC Bus Power Consumption during Cruise Condition ........... A-3
Table AS - Main AC Bus Power Consumption during Taxi Condition .................... A 4
Table A.6 - Main AC Bus Power Comumption during Cruise Condition ................. A-5
Table A.7 - AC Instruments and Engine Fuel Control Bus Power Consumption ...... A d
Table A.8 - Essential DC Bus Power Consumption during Taxi Condition .............. A-7
Table A.9 - Essential DC Bus Power Connimption during Cruise Condition ......... A40
Table A.10 - Main DC Bus Power Consumption during Taxi Condition ................ A43 Table AS 1 - Main DC Bus Power Consumption during Cruise Condition ............. A45
Table B . 1 - Y-Y & A-Y Open-Circuit Test Data .............................................. B-4 Table 8.2 -. Excitation Test Data ................... ,.., ............................................. B-5
............. ........ .................. Table B . 3 - Y,Y & A-Y Short-Circuit Test Data .. ........ B-7
Table 8.4 . Y-Y & A-Y Short-Circuit Test Data Between Windings 1 & K ............. B-1 l Table E . 1 . Essentiai Branch AC Load ChecMist .............................. ... ....................... E- 1
Table E.2 . Essential Branch AC Load Checklist "AC Instruments and ....................................................................... Engine Fuel Control Bus" E-2
Table E.3 œ Essential Branch DC Load Checklist ........................................................ E-3 Tabfe E.4 . Main Branch AC Load Checklist .........................~.................................... E-5
Table E S . Main Branch DC Load Checklist ............................................................. E-6
xiv
List of Photographs
Photograph D.l O AVTRON Model Generator Sensor Connections on AC Bus ....... D-1 Photograph D.2 O AVTRON Mode1 Recording Equipment Setup ............................. D-1 Photograph D.3 O AVTRON Mode1 TRU Sensor Connections on DC Bus ............... D-2 Photograph D.4 O AVIRON Model 9 kW DC Load ................................................ D-2
.................................... . Photograph D S AVTRON Mode1 Load A "Phases B & C" D-3 O .............*..............**.....*.......*.**..*..*..**.... Photograph D.6 AVTRON Mode1 Load B D-3 . Photograph D.7 AVTRON Model Load D ............................................................... D-4
Photograph D.8 O Aircraft Trial Recording Equiprnent Setup .................................... D-4 . ................. Photograph D.9 A i r c d Trial Distribution Panel AC Bus Connections D-5 . ........... Photograph D . 10 Aircmft Triai The-Phase AC Bus Current Connections D-5
Photograph D.11 O A i r c d Trial TRU DC Voltage and Current Connections .......... D-6
Nomenclature
A Amps AC Alternathg Current
'c. - - Approximately Equal To ATM Air Turbine Motor Avg (A) Average Current Avg (W) Average Power AWG Amencan Wire Gauge C Capacitance CC Canadian Cargo CF Canadian Forces CFB Canadian Forces Base d Direct Axis dB Decibel DC Direct Current A Delta At Step Width DiN Distortion Index DOS Disk Operating System EASYS Environmental Control and Analysis System
EG Generator Voltage EMI Electromagnetic Interference EMTP Electromagnetic Transients Program ESD Electrostatic Discharge FFT Fast Fourier Transfonn h Harmonic HF High Frequency HP Hewlett Packard HPM Hi&-Power Microwave Hz Hertz IEEE Institute of Electricai and Electronic Engineers
%O No Load Generator Field Current
LC Excitation Current
ms
NEMP NETE
OEM n
9
Q Ra R RCCR
Rte
RMC S S
SPD STD
kilo Volt-Amps Inductance Logarithmic millihenry Military Magnetic Motive Force Metal-Oxide Varistors miIlisecond Nuclear Electrornagnetic Pulse Naval Engineering Test Establishment Original Equipment Manufacturer Ohm Converter Pulse Number Percentage Power Persod Computer Power Factor Phase
pi Quadrature Axis Reactive Power Armature Resistance
Resistance Reverse Current Cutout Relays Direct Current Resistance Royal Military College Complex Power Second Surge Protective Device Standard Bdancing Transformer Direct Axis Open Circuit Subtransient Tirne Constant Direct Axis Open Circuit Transient Tirne Constant Period Total Harmonic Distortion Telephone Influence Factor
TRU v VA VAC VAR
VDC w
Transformer Rectifier Unit Volt
Volt- Amps Volt Altemathg Current Volt-Amps Reactive Volt Direct Current Watt Fundamental Frequency Steady-State Reactance Armature Leakage Reactance Direct Axis S ynchronous Reactance Direct Axis Transient Reactance Direct Axis Subtransient Reactance Quadrature Axis Synchronous Reactance Quadrature Axis Subtransient Reactance Xero Sequence Reactance Admittance
W Y ~ Impedance
Chapter 1 Introduction
1.1 General
During the past few decades, power system engineers have heightened their
awareness and concem regarding the power quality of electric power distribution systems
[1,2]. The concem and awareness is due prirnady to the increase in number and
application of nonlinear power electronic devices used in the control of power apparatus
and utilization of static power converters. Furthemore, sporadic degradatioii of power
quality can be attnbuted to sags, swells, overvoltage, and cunent transients in power
systems.
Voltage and current harmonics, including sporadic tmnsients, are major electncal
system perturbations, which can cause significant elecîrical waveform distortion. These
perturbations cm significantly impair the performance and operation of electricai and
electronic equipment. The prevailing sources of undesired harmonics and trruisients [3]
are numerous and varied, includiag transfomiers, nonlinear power devices such as silicon
controlled rectifiers (SCR), nonlinear loads such as the static power converter, and a
sudden change (ktching operation or fault condition) in the electricai condition of a
system. It is well documented that static power converters which transform alternating
current (AC) to direct current (DC) inherently inject harmonic cunents into the AC side
of the distribution system. These harmonics cause additional losses and heating in
machines, relay instability, overvoltages due to resonance, instability of controllers, and
noise on communication lines [4].
The future use of nonlinear loads is expected to increase since these loads are
generally highly efficient. Unfortunately, as the use of nonlinear loads increases, current
and voltage waveform distortion and harmonic content is expected to rise. This rise will
gradually degrade overall system performance unless adequate measures are adopted to
control and maintain power quaiity. The graduai degradation in system performance can
result in a decrease in system efficiency and reliability , there b y causkg premature
damage or upset (temporary malfùnction) to electronic components and systems. To
identiQ the aforementioned undesirable perturbations, it is essentid that system engineers
conduct an overall assessrnent of the electrical environment. These assessments, or
power quaiity studies, c m provide usefùi information on the performance of existing or
fiiture systems during normal or abnomal operating conditions such as:
1. generator and Ioad phase unbaiances;
2. voltage and current switching m i e n t characteristics; and
3. steady-state load flow profile (voltage and current magnitude).
The control or enhancement measures of power quality may be realited through
the use of hannonic Blten or surge protective devices. Hmonic filtea [3] in gened are
designed to reduce the effects of harmonic penetration in power systems and surge
protective devices [SI are used to divert the i m h transient current away frorn the
equipment while lirniting the pe& transient voltage. The harmonic filter or surge
protective device should be installed in power systems when it has been detedned that
the recommended harmonic content or transient limits have been exceeded [1,6,7,8].
Aircraft electrical distribution systems provide power to various eiectrical busses
and avionics equipment and subsystems. The present and fùture use of electronic
components for aircraft avionics and control systems has increased the demand for high
quality electrical powet [9]. Excessive hamonic content, and overvoltage or current
transients (e.g. surges, spikes) in an eleceicai power system could remit in a mission
abort due to spurious or erratic operation of flight essential systems, or could adversely
affect the performance of critical mission systems such as the inertial navigation system,
autopilot system, or communication systems. The intent of this thesis is to investigate the
eleceical power quality of the C d a n Forces CC-130 Hercules aircraft eleceical
distribution system through the use of computer simulation, laboratory models, and
aircrafi measurements for validation.
1.2 Background
An elecûical distribution system, which provides a constant sinusoidal voltage
magnitude at a single and constant fkequency, would be classified as ideal. In practice
howeve. an idealized electricai system does not exisk as a constant fiequency and
voltage magnitude cannot be attained. Any deviation in fiequency and or magnitude
from a pure sinusoidai waveshape results in waveform distortion. A distorted sinusoid
will result in voltage and cunent hamionic components and the effects of these harmonies
on power systems result in degradation of power quality thereby reducing system
performance and efficiency.
Funire advancsd aircmft avionic systerns will require reliable, redundant, and
unintemptable electncal power to supply flight and mission criticai loads. The Canadian
Forces CC-130 Hercules fleet of aircrafi is scheduled for an avionics update, which will
include sophisticated, sensitive electronic equipment. The power quality required for this
update may not be adequate since the existing electrical distribution system was designed
to satis@ load requirements of the 1950's.
13.1 Harmonics in Distribution Systems
During the 1920's and early 1930's, power system engineea recognized the
importaace of harrnonics in distribution systems when they observed significant
distortion in the voltage and c m n t waveforms [IO]. During this period, the effects of
harmo nics in synchronous and inductance machines, including telecommunication
interference were investigated.
The reaction of industry to harmonic countemeasures during this period was to
design equipment that would tolerate increases in harmonic content. Recent
developments and the proliferating use of power semiconductor devices and highly
efficient nodinear loads have caused an additional increase in harmonic pollution in
power systems resulting in a growing concem in the power industry.
An important goal of this thesis is to identify the characteristic harmonics, and
switching voltage and current tninsients in the CC-130 Hercules aircraft electrical
distribution system. The characteristics of harmonics and switching transients are
hct ions of both the hamonic source and the system response. The system response to
harmonics is determhed by the inductance and capacitance interaction and damping
provided by loads and losses. Static power converters are significant harmonic
generators by virtue of their cyclic operation. The conversion fkom AC to DC power in
the aircraft distribution system is accomplished with the use of transformer rectifier units
(TRUs). These units have been identi fied as a signi ficant source of harmonics [4].
Numerous papers and reports [Il-171 have been published on the topic of
harmonic sources. In general, harrnonics result fiom the nonlinear operating
characteristics of semiconductor power devices and loads on the system. Sources of
harmonics that can cause harmonic penetration into AC distribution systems are:
1. rnagnetiPng currents in transfomers and synchronous machines;
2. tooth ripple in the voltage waveform of rotating machinery;
3. power conversion equipment and rectifiers; and
4. nonlinear loads.
Excessive harmonic currents have the effect of reducing the life expectancy of
equipment and degrading overall power quality. Equipment may be subjected to
unreliable operation due to failure or upset. Some of the major effects of harmonics
include [ 1 31:
excessive losses and heating of induction and synchronous machines;
unexpected tripping of sensitive loads;
dielectric breakdown;
overvoltage and excessive currents;
torsional oscillations on rotating rnachinery;
inductive interference with communication circuits; and
relay malfunctions.
1.2.2 Electrical Transients in Distribution Systems
Electrical transients on power systems cm cause failure, permanent degradation,
or temporary malfunction of electricd or electronic components and systems. The
transient penod is usudly very short. However, during this period circuit components are
subjected to extreme voltage levels. Cooper and Mundsinger [6] indicate that transients
can rise to peak magnitudes of several thouand volts within a few nanoseconds and
decay within microseconds. They also indicate that transients cm fmd their way through
DC power supplies and into electronic circuits. Manufacturen and users of industrial,
military, and even consumer electronic equipment realize the importance of providing
effective transient protection.
Since the 19601s, as indicated by Staridler [5] , the concern for transient effects on
electronic components has increased. This trend can be expected to continue due to the
following reasons:
1. increasing derabi l i ty (sensitivity to transients) of devices;
2. vulnerable devices aud systems are proliferating;
3. increased awareness of the existence of transients; and
4. operationai criticality of vulnerable devices.
Devices such as very large-scale integrated circuits (VLSI) are much more
vulnerable to transient effects due to their low operating voltages than earlier electronic
circuits that used component devices such as vacuum tubes and relays. The trend towards
designing denser and highly efficient integrated devices that operate at very low voltages
(r 5.0 volt) is increasing. As the operating voltages decrease, circuits will become more
susceptible to transient effects. The consumers of vulnerable systems are requesting
appropriate protective measures. For example, surge protective power bars are widely
used to protect desktop cornputers against transient overvoltages.
Transient overvoltage in electncai circuits may be caused from ziiy of the
following:
i . lightning;
2. electrostatic discharge (ESD);
3. electromagnetic pulse from nuclear weapons (NEW);
4. hi&-power microwave weapons (HPM);
5. curent limiting fuse operation;
6. switching of reactive loads; and
7. faults.
One of the author's objective is to examine the transient phenomena associated
with load switching operations. Transient overvoltages that are caused by switching
reactive loads are a cornmon cause of damage or upset of electronic circuits and systems
[2]. It is important to realize that a transient may propagate fkom one conductor to
another by meam of electrostatic or electromagnetic coupling.
Standler [SI states that electrical transients can cause two types of adverse
outcornes in sensitive electronic and electtical circuits and systems: "damage or upset".
Damage may be defined as a permanent failure of hardware. A system that has
been damaged may experience permanent or partial failure. To recover fiom damage it is
necessary to repair or replace the damaged component.
Upset may be defined as a temporary malhction of a system. Repairs or
replacement of hardware is not required when upset has occurred. An example of upset
occurs when volatile memory in a computer hm lost its content during a power
interruption.
Methods for transient overvoltage protection cm be categorized into four
classifications:
1. shielding and grounding;
2. application of filters;
3. application of nonlinear protective devices; and
4. development of light-based (fiber-optic) equipment not affected by transients.
As discussed by Staadler [5], shielding is important; however it does not offer
&cient protection against transient sources such as electromagnetic fields fkom either
lightning or nuclea. weapons, since the integrity of the shield is compromised. Examples
of shielding concems are: windows in an aircraft, inadequate cable connections, or long
transmission and antenna lines.
Standler [SI also indicates that filters alone are not commonly used as transient
protective devices. They are usually designed as low pass filters and are commonly
c o ~ e c t e d in series with the power source to achieve high frequency electrornagnetic
attenuation.
The nodinear or surge protective device (SPD) is used to divert surge current
away fkom sensitive electronic or electrical equipment while limiting the peak voltage.
Many types of protective devices are available, and they each offer their own particular
operating characteristics. The decision to specify an SPD for a particuiar application
depends on the operathg properties of the device and the surge characteristics. Examples
of SPDs are:
1. spark gaps;
2. nodineai. resistors such as:
a. siIicon carbide varistors; and
b. metal-oxide varistors (MOV);
3. serniconductor diodes and rectifiers;
4. thyristors; and
5. avalanche and zener diodes.
1.2.3 Aircraft Electrical Systems
A i r c d electrical power systems ofien comprise two or more engine driven
generators, which suppiy AC power to nurnerous AC distribution busses. The AC engine
dnven generators on most American and British aerospace aircraft are usually connected
in a pamllel configuration while the Canadian Forces aerospace aircrafi configurations are
singly connected to individual busses. The DC power is supplied by various types of
power static converters (AC to DC converters) which are known in the aerospace industry
as transformer rectifier units (TKUs). As previously mentioned in section 1.2.1, static
power converters can be considered as harmonic generators by virtue of their cyclic
operation. These units cm increase wavefom distortion and harmonic content by
Uijecting harmonic currents into the AC side of the electrical system.
Digital simulation of aircrafi electrical power systems have been conducted on
various models [18,19]. A paper published by Woods [20] presents his resuits fkom a
computer simulation model which was derived from a single channel aircraft electrical
system with AC and DC power loads. The model included a 150 kVA generator,
resistive and reactive AC loads, and a resistive DC load. The simulation runs were
conducted during steady-state and transient Ioading for various AC and DC load levels
and irnplernented on the environmentai control and analysis system (EASYS) general
purpose computer program which was developed by Boeing aerospace. The intent of the
simulation work was to investigate models which were as simple as possible to enable the
evaluation of the effects of rectification and load transients on aircraft electrical power
quality. The conclusions indicated that simplified generator models were capable of
producing adequate resdts when evaluating overall system performance. The
documented plots show various waveforms of voltages and currents in the time domain
but no results were published in the frequency domain.
Fanthorne and Kenleborough [2 11 describe their modelling scheme and digital
simulation results of an aircraft electrical power system. The simulation model included
two parailel connected 60 kVA generators, a radar load, one three-phase twelve-pulse
TRU, and a DC resistive load. The details of the radar model were omitted due to security
classification. The documented plots show various waveforms produced by the TRU,
radar, and generators. A frequency domain plot representing the system with a radar load
is included. The frequency plot shows that the highest harmonic component is the 5"
harmonic at 6.39% of the fimdarnental.
1.3 Thesis Objective
The objective of this thesis is to investigate the electrical power quality of an
aircrafl electrical power distribution system through the use of computer simulation,
laboratory models, and aircraft measurements. In order to realize this objective, the
following goals were specified:
1. develop a singie branch simulation model and laboratory model of the existing
CC-130E Hercules aircraft electrical power distribution system for harmonic
content, steady-state, and surge data analysis;
2. perform on site aircraft measurements to gather harmonie, steady-state, and
mrge data for cornparison and validation with anaiyticd rnodels;
3. compare the simulation model and Iaboratory model with aircrafl
measurement results and MU. STD-704 ( 1 May 91) [22]; and
4. if required, identi@ appropriate conditioning devices (filters/protective
circuits) which may enhance overail system performance (improve power
quality).
Chapter 2 Theory
2.1 CC-130E Electrical Distribution System
The aircraft electrical distribution system supplies AC and rectified DC power to
AC and DC busses [23]. Four engine-driven heavy-duty AC generators provide three-
phase regulated primary voltage to four groups of AC distribution busses. A robust
matrix of bus tie contactors (relays) are used to connect the AC distribution busses to the
generators. A fifth AC generator, driven by an air turbine motor, serves as a standby
power source. The DC power distribution system is comprised of four transformer-
rectifier units (TRUs), reverse-current cutout relays (RCCRs), and four DC busses
identified as the essential, main, isolated, and battery bus. During normal operating flight
conditions, the essentiai bus provides DC power to the isolated bus. The isolated DC bus
Loads were tabulated at less than 8.0 A. This DC magnitude was considered insignificant
compared to the essential bus tabulated loading as shown in Table A.2 in Annex A and
as such, the isolated bus was not modelled. The battery bus only provides power via a 36
ampere-hour 26.4 VDC battery to flight-essential loads during emergency flight
conditions when DC power cannot be provided by both the essentiai and main DC busses.
As a resdt of this unique flight condition, the battery bus was not modelled. Figure 2.1
shows a simplified single-phase aircraft distribution system block diagram.
The AC distribution system consists of four AC busses and is identified as the
lefi-hand, essential, main, and right-hand bus. During normal operating conditions, each
generator supplies power to one AC bus. For example:
1. number one generator connects to the left-hand bus;
2. number two generator connects to the essentiai bus;
AC BUS DISTRIBUTION SYSTEM EXT AC u
AC #1 #2 # 1 #2 AC LOADS ESS ESS MAIN MAIN LOMS
24 Vdc TRU TRU l'RU TRU BAITERY
DC DC DC LOADS LOADS LOADS
AIR TURBINE MOTOR GENERATOR
NORMAL CONDITION
LX$, STANDBY PO-
> GROUNDONLY
DC LOADS
Figure 2.1 - CC430 Electical Power Distribution System
uSimplified Singie Phase Block Diagram"
3. number three generator connects to the main bus; and
4. number four generator connects to the right-hand bus.
It is important to note that the AC generators are never connected in parailel.
All four engine-dnven generators are identical. Each generator is rated at 40 kVA
during flight conditions and provides a regulated three-phase 1 W200 VAC at 400 Hz.
The output system fiequency is dependent on engine speed and allowed to Vary between
380 and 420 Hz. The generator provides an output fiequency of 400 Hz when the engine
operates at 100 percent and has a separate control system, which consists of a voltage
regulator, under-frequency detection circuit, and control panel. Contmlling the excitation
shunt field cunent regulates the generator output voltage. The block diagram in Figure
2.2 depicts a typical generating control system.
AC BUS
D r n L l T I O N
+= FREQvENcY , S E N m
RELAY
TO AC
BUSSES
Figure 23 - Primary AC Genenting Control System
2.1.1 AC Bus Distribution System
The AC bus distribution system is common to ail generators and automatically
connects the generator output voltage to groups of AC busses in a sequential manner
without parallehg the generators. A simplified AC bus distribution system is shown in
Figure 2.3. The bus distribution components consist of bus ties (relays K5 to K8) and
main generator contactors (relays K1 to K4). Al1 relays KI to K8 are shown in the de-
energized position. The system operates as described in the following panigraph.
Figure 23 - Single Line Genentor to AC Bus Distribution System
The fkst on line generator c o ~ e c t s to both the essential and main AC busses
through bus tie relays K6 or K7 and the corresponding generator relay K 1, K2, K3, or K4.
Any two generaton will supply power to al1 four busses through either K6 or K7 and K5
or K8, and the corresponding generator relays. Since the generators never parallel, the
busses must divide between the generators. Assuming al1 generators are on line,
generator 1 provides power to the LH bus through K1 and K5, generator 2 provides
power to the essential bus through K2 and K6, generator 3 provides power to the main
bus thmugh K3 and K7, and generator 4 provides power to the RH bus through K4 and
K8. The generator, bus, and relay contactor comection matrix is tabuiated in Table 2.1.
Table 2.1 - AC Generator to AC Bus Connection Matrix
Cenerators Ac I Contactors AC Busses
Note: X refen to energized condition.
2.1.2 DC Bus Distribution System
As shown in Figure 2.4, the DC distribution system supplies power to a battery
bus, isolation bus, essential bus, and main bus. The DC busses can be powered by the
TRUs, the battery, or extemal DC power. During nomial operating conditions, the
rectified DC power is supplied by the TRUs and each unit provides a nominal 28.0 VDC.
The DC busses are interconnected in such a way that the current flows fiom bus to bus
under certain conditions. The current flow is controlled by reverse current relays (RCRs).
4
X
X
X X
x l x X X X
1 X
X X X
X X X
The fiinction of the TRU is to convert three-phase AC power fiom the essential
and main AC bus to a nominal 28.0 W C for the DC busses. The TRUs function in pairs.
For example, one pair of TRUs supplies DC power to the essential DC bus and the other
LH
1 1 1
1 1 1
KI X
2
X
X
X X
--7
1
K3
X
X X X
K2
X
3
X
X
X
X
X
X X
RH
1 3 4 3 4 4 3 4 4
K4 ESS 1 2 3 4 2 I 1 2 2 3 2 2 1
X X X
X X X
x x x x x p 4 4
X
X
X X X X X X X 2 X
MAIN 1 2 3 4 2 3 4 3 4 3 3 4 3
2 2 X
K5
3 3
X
X X
X
X I
X
X
X - - X
K6 X X
X X
X
X X X X X
X X X X X
X
K7
X
X X X X X X
K8
X
X X X X
X X X X 2 X X X X X 2
X X X X X X 4
pair to the main DC bus. Each TRU can supply up to 200 amps of DC current at
28.0 VDC.
FLIGHT
GROUM) ONLY
1 ESSPFïW 1 AC BUS
ni #2 ESS ESS
TRU TRU I I L
AC BUS u ,+F+, w MAIN
GROUND ONLY
( A m )
Figure 2.4 - DC Bus System
The RCRs are used to prevent the TRU output current from flowing into the
TRUs during an AC power system failure and also to prevent essentiai DC power fiom
flowing into the main DC bus during nonnal flight conditions. The RCR located between
the isolated and essential DC bus is used to prevent current flow fiom the isolated to the
essential bus in the event of a complete primary AC power failure in flight. During
certain ground oniy operations, it is essential to have the battery power the isolated,
essential, and main busses through the RCRs.
2.1.3 AC and DC Loading
The system loading was obtained by performing a theoretical summation of the
AC and DC elecûical loads of the aircraft. The AC and DC load representation for both
the simulation and laboratory models were derived from the surn of individual aircraft
equi pment reai and reactive po wer consumption data [23]. Inductive and resistive
components were used to represent the AC loads, and the DC loads were represented by
single resistive elements. The tabulation of the aircraft equipment power consurnption on
the essential and main AC and DC busses during cruise and taxi conditions are found in
Appendix A, Tables A. 1 and A.2.
2.2 Harmonic Analysis
The use of loads with nonlinear charactenstics, such as static power converters,
result in harmonic voltage and current generation and penetration into the AC side of the
electrical distribution system [17]. These harrnonics can cause significant primary AC
waveform distortion and undesirable effects on system loads, such as overheating?
electromagnetic interference (EMI), and overvoltages due to resonance.
The d e f ~ t i o n of a harmonic is: "a sinusoidal component of a periodic wave or
quantity having a kquency that is an integral multiple of the fundamental fiequency"
[24]. Harmonies, therefore, can be considered as voltages andlor currents present on an
eleceical distribution system at some multiple of the fundamental operathg fkequency.
For example, the fkquency component which is twice the fundamental kquency is
called a second harmonic.
Harmonic d y s i s is the process in which the amplitudes and phase angle
between the fiuidamental and higher order hannonic components of a periodic waveform
are determined. As previously mentioned in section 1.2, a distorted sinusoidal wavefom
resuits in voltage and current harmonic components. in 1822 the French mathematician
kan Baptiste Joseph Fourier (1768-1830), in his study and analysis of heat flow,
discovered a trigonometric series representation of a periodic hction. This series is
known as the Fourier series aad establishes a relationship between the tirne domain and
the fiequency domain of a continuous periodic wavefom (function). Fourier postdated
that any continuous periodic fùnction could be represented by an infinite sum of sine or
cosine functions that are harmonically related. Thus given that f ( t ) is periodic, with
fiuidarnedal period (T), Fourier was able to show that f ( t ) can be expressed as:
where a, is the average value of the function f ( t ) , a,, and b, are the coefficients of the
series, and w, represents the fundamental frequency ($1 of the periodic function. The
coefficients are the rectanguiar components of the n ' harmonic vector such that:
A, LQ>, = a, + jb,
with magnitude
and phase angle
The average value a, is derived fiom the following expression:
and the senes coefficient a, os
1 a,, = - - f (t)Cos(nr)dr
I r "
and b , as
The harmonic profile (fiequency spectnim) of a periodic function (wavefom) is
usually obtained fiom the use of Fast Fourier Transform (FFT) dgorithms. The
simulation sohare program Harmonic, which is a Fourier anaiysis program for
MicroTrd, a transient analysis program, was used to obtain the harmonic profile fiom
the tirne domain simulation waveforms.
2.2.1 Harmonic Distortion - a figure of merit
There are several classical measures of electric power quaiity. For penodic
wavefonns of period T, the most widely used measure in North America is the Total
H m o n i c Distortion (THD) which is defined in terms of the amplitude of the hmonics.
The THD is used as a figure of merit to describe the effect of distortion on the electrical
distribution system. Other methods are also used such as telephone influence factor (RF)
and distortion index (DM). The distortion term used in this work to chamcterize the
hamionic distortion is the THD since the current and proposed IEEE harmonic standards
are based on THD vaiues. The total harmonic distortion for this study is defmed as:
U, = fiindamental component of the RMS current or voltage
U, to Un = RMS of harmonic components
During certain load conditions, the THD values may be misleading when the
fundamental component of the curent or voltage varies independently fiom the actud
magnitudes of the harmonic components. For example, high i'HD values of current can
be misleading at low load levels. Therefore, THD values shouid be used as a figure of
merit only and in association with the electncal distribution system-loading
configuration.
2.3 Transformer Rectifier Units
Static power converters are designed to provide specific power conversion
requirements and are available for many different types of applications. These include
rectifiers, inverters and cycloconverten. They may be single-phase, three-phase, six-
pulse, and twelve-pulse devices just to name a few. Al1 of these terms are used to
describe different circuit configurations of static power converters.
The aircrafi transformer rectifier units are designed as rectifiers to convert three-
phase 11Y200 VAC at 400 Hz to a nominal 28.0 VDC supply for relays, contactors,
avionics equipment and battery charging. A diagram depicting the aircraft transformer
rectifier unit is shown in Figure 2.5. The diagram shows a three-phase voltage supplying
power to two parallel-connected six-phase transformer rectifiers. Due to the primay
winding characteristics, ( A and Y configuration), a 30 degree phase shift exists between
both secondary voltages. The primary and secondary winding turns ratio are such that
both transfomers provide the same voltage output magnitudes (positive phase sequence
is assumed). As an example of the use of intercomected windings, consider the
arrangement shown in Figure 2.6 (a). The arrangement is comprised of a three-phase
transformer or a bank of thm single-phase transfomers having a primary winding and
three independent secondary windings for each phase. The primary windings connection
rnay be either A or Y . When the three-phase voltages applied to the primary windings
are balanced, the secondary windings deliver balanced six-phase voltages as shown in the
28 ~9 cl4
T T '
Figure 2.5 - Three-Phase Twelve-Pulse Transformer RecMer Unit
vector diagram of Figure 2.6 (b). For an ideal transformer, the following relationship
applies:
where Y, refers to the primary voltage and Y, the secondary voltage. The expression
Np/Ns is the transformer winding tums ratio between the primary and secondary
windings. Equation (2-9) can be rearranged as:
where V' + V, represents the surn of vector V, in figure 2.6 (b).
The vector diagram of figure 2.6 (b) can be used to show that:
Let
where n = N s / N p .
Therefore,
Note that the six-phase line to neutrai voltage equals f i times the voltage of one
secondary winding. Al1 secondary windings on the same transformer are drawn parallei
to one another as shown in Figure 2.6 (c). The aircraft TRUs f'unction as twelve pulse
Iine commutated converters and are designed to supply 5.0 to 200.0 DC amps. Thus, the
AC supply voltage is used as commutating voltage and provides either positive or
negative b i s across the diodes for hirn on or tum off. It suffices to Say that the
harmonics produced by line commutated converters are related to the pulse number of the
device [4]. For the ideal situation of instantaneous commutation between the conduchg
elements (diodes in this case), the hannonics which are generated on the AC side of the
converter and their magnitudes are given by the following relationships:
w here
h = hannonic number
I, = harmonic current magnitude
n = any integer 1,2,3, ... p = converter pulse number
1, = hindarnental current magnitude.
Therefore, for a twelve-puise converter, such as the one shown in Figure 2.5, the major
harmonic currents generated are the characteristic harmonics of order 12 x n t 1. The
characteristic harmonics of order 12 x n - l are the negative sequence currents, and the
order of 12 x n + l are the positive sequence currents under a perfectly balanced condition
[Il]. The magnitudes of the hmonic currents decrease as the order increases. It must
be emphasized that additional hmonics other than the harmonic characteristic (non-
characteristic harmonic current) of the converter may be present due to unbalances in the
circuits and unsymmetrical switching element conduction angles.
As shown in Figure 2.5, the input filter used to reduce the level of harmonics
generated by the TRU consists of capacitoa C3 to Cl 1 and inducton LI to L6. The
output filter components are Cl, C2, L7, and the baiancing transformer TA.
The typical values of harmonic currents as a percentage of the fùndarnental
current generated by a thtee-phase twelve-puise converter are tabulated in Table 2.2 [Il].
Table 2.2 - Typical Values of Harmonic Currents Generated
by a Twelve-Pulse Converter
2.4 Modelling the Network's Elements
2.4.1 Line Mode1
b
Lines or distribution conductors can be represented by an equivalent senes
Current = % of fundamental component
7
0.2
Harmonic Order Current
%
inductive and resistive component. For small conductors (AWG 2 1) in 60 Hz power
systems, the cable resistance is greater than the inductive reactance [25,26]. In 400 Hz
5
0.2
systems, (vice 60 Hz), the conductor inductive reactance is approximately 6.7 times
greater. Therefore, 400 Hz systems possess an inherent advantage of surge suppression
11
6 -9
during system transient conditions due to larger inductive reactance. Typicd values of
resistance and inductive reactance for one Kilometre length of copper conductor size 4
and 12 AWG at 60 and 400 Hz is compared in Table 2.3. The impedance of a conductor
cm be represented as:
where
13
5.2
R, = conductor resistance
2 @LI = inductive reactance
I
17
O. 1
19
O. 1
23
2.0
25
1.8
Table 2.3 - Copper Conductor Characteristics nt 60 and 400 Hz
I * refen to a fist approximation where 2 f l is used to determine the inductive reactance
Conductor Size (A WG]
4 12
1 n per conductor per Kilometre at 25" C I 1 AWG = American Wke Gauge I
Resistance (DC) 0.863
2.4.2 Reactive Load Mode1
Power distribution system loads cm be modelled as equivalent lumped load
component elements. One method of achieving this mode1 is to sum the complex power
consumption of individual system loads to represent a single equivalent system load
knowiag the total system power consumption. For example, assuming that the total
power consumption in Volt-Amps (VA) is known including power factor (PF) for a given
distribution system then the load elements can be determined fiom the following
expressions [27]:
Inductive Reactance (60 Hz) 0.3724
v2 S, = PL + jQ, = VI' = v'Y,' = - - 0
Inductive Reactance* (400 Hz) 2.482 a
5.940 Q 1 0.448 n
From the above expressions, the load component elements can be represented as either a
2.987 Q
series or parailel circuit. As a parallel circuit, the resistance and inductance values cm be
found fiom the following equations:
and
As a series circuit
where
o = 27rf (where f = fundamentai fkquency in Hz)
V = line voltage (V)
R = load resistance (R)
L = load inductance (H)
S = load (VA)
PF = load power factor
PL = load reai power (W)
QL = load reactive power (VAR)
Y, = load shunt admittance (a-') 2, = load impedance (R)
The series and parallel Ioad models are shown in Figure 2.7. Pileggi et al. [Il, recommends a shunt representation when the nature of the loads are not well defined.
(a) Series Model (b) PanIlel Model
Figure 2.7 - Static Load Models
2.4.3 Generator Mode1
The engine dnven generator is simuiated using the simulation program,
~ i c r o ~ r d , and the manufacturer's data. The mechanical part of the power plant,
including rotational speed, is assumed to be constant (ie. torsional vibrations, changes in
rotational speed, and voltage regdation are not considered in this study). Table 2.4
depicts the manufacturer's generator parameten, which are used as input data in the
simulation prognun to represent the aircraft elecûical generating systern. The
mathematical derivation of the generator will not be discussed, since it is beyond the
scope of this thesis. The theoretical derivation cm be found in the Electricai Magnetic
Transient Program (EMTP) theory book [28].
Table 2.4 - Generator Parameters
Mac hine Parame ters
Description
I R, @*uJ ( Armature resistance I
1 X, @.u.) ( Quadrature axis synchronous reactance 1
x, @Je) x, @+uJ
1 X, @.u.) 1 Direct axis transient reactance I
Armature leakage reactance Direct axis synchronous reactance
X: @a.) X, @.u.)
1 1 No Load field current 1
Direct axis subtransient reactance Quadrature axis subtransient reactance
x, @-u.) Ti (s) Ti (s)
XI, (s)
Xero sequence reactance Direct axis open-circuit transient t h e constant Direct axis open-circuit subtransient time constant
Quadrature axis open-circuit ûansient thne constant
Chapter 3 Implementation
3.1 General
In order to validate and veriQ the harmonic content and electricd transient
switching characteristics in an aircraft electrical power distribution system, a three phase
approach was chosen. Phase one, the simulation phase, was implemented with
~ i c r o ~ r a n ~ , a simulation software package designed to analyze electrical power systems
including electronic components during steady-state and transient conditions. The
second phase, the simulation verification and validation phase, was conducted in the
AVTRON shop; a laboratory environment where actud aircraft components were used.
The laboratory mode1 was designed to emulate a single aircraft electrical distribution
branch and to veng the accuracy of the simulation results. The fuial phase was
identified as the field data acquisition phase where on site aircrafl measurements were
conducted on a Canadian Force Hercules transport CC-130E aircrafi. Phase two and
three were used to venfy and validate phase one.
3.2 Development of the System Mode1
The model of the aimafi electrical power distribution system was developed to
represent the physical atûibutes of the aircraft power system as closely as possible. This
cornmensurates with one of the main goals of this thesis; - to develop a single branch
simulation and laboratory model of the existing CC-130E aircraft electrical power
disiribution system for steady-state, harmonic content, and surge data analysis. The
model configuration as shown in Figure 3.1, was designed to simulate two of four
possible distribution branches, essential and main, of the aircrafi electrical power system.
The model consists of one constant speed aircraft engine driven generator, three-phase
distribution hes, two TRUs, circuit breakers (CB) for coordinathg the removai and
switching on of loads, and lumped distribution system AC and DC louis. The loads are
divided into two categories: essential Loads and main loads. These loads are represented
as equivalent three-phase and single-phase lumped resistive and inductive components.
AC BUS
1 AC
LOADS
TRU TRU
AC LOADS
DC LOADS
Figure 3.1 - Single Line Block Diagram of Test Set-Up
There are several basic models which can be adopted to study a three-phase
synchronous generator: the phase coordinate approach [21], the 'ci' axis or direct axis and
'q' axis or quadrature axis fr<ime of reference in which the phase quantities are lumped on
MO orthogonal axes (Park's coordinates) [29], and other standard techniques such as the
voltage EG behind the steady-state reactance X, [27l. The Park's voltage equation
parameters are used in this thesis to mode1 the aircrafi generator since the parameters
were provided to the author by the manufacturer (Sundstrand Advanced Technology
Corporation) and the simulation program has the mathematical capability of utilizhg
these variables ditectly. The generator rating and parameters are tabulated in Table 3.1.
Several assumptions must be made when considering the use of Park's
transformation on synchronous generators. These are:
each machine winding generates a sinusoidally spaced disûibuted magnetic
motive force (mmf);
the rotor magnetic field and load circuits are symrneûicai about both the direct
"d" axis and the quadrature "q" axis;
the rotor slots have negligible effect on inductive values due to rotor position;
the darnper winding is replaced by two equivaient damper circuits; one
each of the d-axis and q-axis; and
the effects of saturation, hysterisis, and eddy cunents in dl magnetic circuits
are neglected.
Table 3.1 - Generator Rating and Parameter Values
t
Machine Parameter
Ra @.u.) X, @.u.) X, @A) x, (P-u.1
Numerical Value
0.023644
O, 10 1800
2,502000
2.326700
Machine Rating
F (Hz) S (KVA)
PF
v (ms)
Numerical Value
400.00 4
40.00
0.75 3
1 1 5.00/200.00 L
3.2.2 Distribution Conductors
Three different conductor sizes were used to implement the AC and DC
laboratory power distribution system. The three-phase AC lines consisted of three 70-
foot lengths of number 4 AWG and h e e 25-foot lengths of 12 AWG copper stranded
conductors. The number 4 AWG conductors were used to transfer the generator output
power to the AC bus. The number 12 wire gauge conducton were used to provide power
fiom the the-phase AC bus (end of 70-feet No. 4 AWG conducton) to the input of two
parallel comected TRUs. The 00 AWG conductor was used as a DC distribution line to
provide DC power from the TRU output terminais (DC bus) to a lOKW DC resistive
load.
The length and size of the conductors used to develop the AC and DC distribution
lines corresponds directly with the aircmft design wiring specifications. The conductor
characteristics such as resistance and inductance, required as input values for @
MicroTran , the simulation prognun, were provided fiom Chapter 3, Table 1
"Characteristics of Copper Conductors" [25] and MIL-W-22759111 F document [3 O].
The impedance inductive value at 400 Hz was derived from linear extrapolations of
known larger wire sizes since the inductive value per unit length of wire at 400 Hz could
not be found in any publication. The approximate calculated resistance and inductive
values per phase for a 70-foot length (a physical length from aircraft generator terminais
to AC distribution bus) of number 4 AWG is 0.01 848 R and 0.021 1 mH respectively.
33.3 Switching Loads
Two aircraft equipment loads were identified fmom the tabuiation of the AC and
DC Power Consumption Equipment Chart [23] as the optimum choice in studying the
transient system response associated with load switching. The loads are identined as the
search radar and the HF radio.
The objective was to select a single-phase and three-phase load for load switching
analysis. The search radar, a single-phase load, was chosen because it consumes an
appreciable amount of cornplex power (1300 VA at 0.96 PF) and the three-phase load
was identified as the HF radio because it consumes approxirnately the same amount of
power (1 11 1 VA at 0.90 PF).
The ideal choice for both the single-phase and three-phase loads were initially
identified as the hydraulic suction pump and the hydraulic auxiliary pump since these
loads consume the largest amount of power on the essential AC bus (2760 VA at
0.70 PF) and (3450 VA at 0.70 PF), respectively. The hydraulic purnps were not
modelled because the specifications (component values) required to mode1 the pump
motors were not available fiom either the pump manufacturer or technical manuals.
Figures 3.2 (a) and (b) depicts the circuit configuration and theoretical component
values to represent the search radar and HF radio.
Main AC Bus Essential AC Bus
(a) Search Radar (b) AF Radio
Figure 3.2 - Essential and Main Branch Transient Loi&
3.2.4 Transformer Rectifier b i t s
The transformer rectifier units which are used in the CC-130E aircraft electrical
distribution system are designed as 6.3 kVA twelve-pulse three-phase static power
converters, which transfomis 400 Hz, 200 VAC (0-0) voltage to a rectified 28 Volt DC.
Static power converters in general are designed for specific applications.
The primary purpose for modelling the TRU is to examine the qualitative and
quantitative degree of voltage distortion and harmonic content which these units impose
on the AC side of the electncai system. The degree of AC power distortion occurs as a
result of the magnitude of harmonic currents injected into the AC side of the power
system. This phenomena occurs as a resuit of voltage commutation of the conducting
semiconductor elements (diodes) which cause cyclic current injection into the AC
system. As previously mentioned in section 2.3, line or voltage commutated converters
produce harmonic characteristics of order h = n x p t 1 where p is the pulse number of
the device and n is any positive integer.
Two TRUs connected in parallel were modelled. The reason for this
configuration is to replicate the aircraft electrical power distribution system as closely as
possible. The essential and main DC aircraft bus power is provided by two paralle1 sets
of TRUs. The ~ i c r o ~ m @ software transient application program (refer to section 3.3)
was used to model and simulate the rectifier units. The technical data required as input
parameters to simulate the TRU, such as, short-circuit and open-circuit test data,
transformer excitation current, secondary winding resistance, and secondary output
voltage were not available fiom the original equipment manufacturer (OEM), Cooper
Industries Incorporated, a leading aerospace manufacturer of rectifier units and one of
two suppliers for the Canadian Air Force market.
An aircraft TRU model No. ECU-23A. serial No. 5868, manufactured by Cooper
Industries was disassembled at RMC to perform open and short-circuit testing and
winding measurements on both the Y - Y and A - Y three-phase transformers. To
determine the transformer secondary winding phase configuration, a dud-channel
oscilloscope and a two-phase 400 Hz AC voltage source were used. The open and short-
circuit transformer parameter values are required as input data for ~ i c r o ~ r a n " to
simulate the T'RU transformers. The transformer model parameter derivation and
laboratory-measured data are shown in Annex B.
3.2.5 AC and DC Loading
The AC and DC electncal system model static loading objective is to emulate
existing aggregate loads that are comected to the essentid and main distribution branches
during aircraft taxi operating condition. The AC and DC Equipment Power Consurnption
Charts [23] including equipment manufacturer's data were used to derive the AC and DC
Ioads. These charts provide a tabulation of most aircraft equipment average power
consumption data during various aireraft operating conditions (loading, taxi, cniise,
landing, etc.) and identiQ equipment loading specifications such as power factor,
cornplex power per unit (VA), number of units, average watts in operating condition, and
source of power derived fiom the essential or main bus. A tabulated list of equipment
power requirement supplied by the essentiai and main AC and DC bus including power
consumption data during taxi and cruise operating conditions is found in Appendix A.
Even though the cruise loading condition was not emulated, the cniise loading profile
was included to show the predicted power consumption difference between taxi and
m i s e conditions.
The AC and DC lumped load component values (inductive and resistive) for both
the essential and main branch loads were derived fiom equations (2-1 9) to (2-23) and the
tabulated r e d t s from Appendix A; Tables A. 1 and A.2 - "Tabulation of the AC and DC
Power Coosumption", respectively. The essentid and main branch theoreticai static load
models are depicted in Figures 3.3 (a) and (b).
AC Bus DC Bus
(a) Essential Bnnch Static Loads
AC Bus DC Bus
(b) Main Branch Static Loads
Figure 3 3 - AC and DC Branch Static Loads
3.3 ~ i c r o ~ r a n ~ Simulation Tool
The simulation model of an aircrafi electrical distribution system was developed
for this thesis using the ~ i c r o ~ r a n @ Personal Cornputer (PC) tool. ~ i c r o ~ r a n ~ is an
implementation of the Electromagnetic Transients Program (EMTP) for personal
cornputers and is produced by ~icroTran@ Power System Analysis Corporation,
Vancouver, BC [31]. The EMTP was f i t developed by Dr. H.W. Dornmel at the
Bonneville Power Administration, Portland, U.S.A.
3.3.1 ~ i c r o ~ r a n " Overview
The program is p r i m d y designed for developing and andyzing electrical power
systems and has the capability of modelling a wide variety of system components such
as: EZ, L, C, linear and noniinear, single-phase and coupled multiphase transmission lines
with constant or tiequency dependent parameters, mdtiwinding power transformes,
synchronous generators, lightning arresten, and power electronic components.
~ i c r o ~ r a n @ was chosen because it has the capability of anaiyzing systern transient
phenornena using differential equations of an electric network step by step in the time
domain fiom t =O to t = t , with a step width At.
~ i c r o ~ m @ is a PC DOS operating system capable of modelling up to 2000
nodes and 2000 branches, and requires a hardware key to operate. ~ i c r o ~ r a n @ allows
the user to analyze the results of the simulation through pphicai displays and numericd
outputs. The analysis package also aids in debugging and refining the simulation model.
To run ~icroTran@ a predefined input data file is required. During the compilation
process the program generates a numericd output data file and a graphical plot file. A
~ i c r o ~ r a n ' optionai add-on program, Harnionic, a Fourier AaalySis Program, was used
to d y z e the model output binary plot files for harmonic content.
33.2 ~ i c r o ~ r a n ' Data Input File
The input data file contains the parameters of the network components, the
request for output variables, and the simulation parameters such as: time step At, and
various control fiags. Each line of data in the data file is referred to as a "card" and it is
80 columns wide. A complete simulation case is cailed a "data deck". The data file is
divided into data groups or sections. The groups that form the data file are as follows:
Case Identiiïcation Card - This line may contain any alphanumenc text
between columns 1 and 80. The card is used to identify the case and define
reactive component assignment;
Time Card - This line includes the tirne step At, the length of the simulation
imsx , and additionai control flags;
Linear and True Nonlinear Branches - This section includes the cards for
simple Iurnped R, L, and C elements, coupled pi circuits, distributed
parameter transmission iines, and nonlinear elements represented with the
compensation method. This section is also used to request branch currents
ancilor branch voltages;
Switches and Piecewise Linear Branches - This section includes time and
voltage dependent switches, nonlinear elements represented as piecewise
linear, and power electronic components such as diodes and thyristors;
Soums - This section includes the voltage and current sources and
synchonous machine data parameters;
User Suppiied Initial Conditions - The user supplied initial conditions
option aiiows the user to specify PO conditions for lumped elements and DC
initiai conditions for transmission lines; and
7. Node Voltages Output - This section is w d to request node voltages
output.
3.4 Simulation Mode1
A model is an abstraction of an actual system and incorporates those elements that
are significmt to the purpose of the model. The elements are significant in that they are
useful in describing, designing, and anaiyzhg reai systems. Models are ofien developed
to substitute real systems when the real system itself is cornplex, expensive, or
unavailable.
The performance of an electrical distribution system is judged by its electrical
characteristics during various loading conditions. The simulation model must be accurate
in terms of al1 parameters that affect the power system voltage, curent flow, and power
factor. The model mua also implement the distribution network in its entirety.
The purpose of the simulation model for this thesis is to emulate the laboratory
modelled aircraft power distribution system and to explore the performance and accuracy
of the mode1 under various controlled operating conditions. Six distinct scenarios were
conducted on the simulation mode1 and identified as Case 1 through 6. The test cases
were designed to emulate as closely as possible the laboratory model taxi loading profile
and test scenarios.
~icro~ran" was used to simulate one engine generator, three-phase AC
distribution conductors, three-phase essentiai and main bus loads, single-phase and three-
phase transient loads, two TRUs, and DC loads to represent the essential and main Bus
loading during taxi conditions.
Case 1 was designed to examine the effects of the TRUs as a distinct load on the
AC bus during a no load condition. During this sceliario, AC and M: loads were not
applied. Scenarios 2 through 4 were developed to emulate loading conditions on the
essential AC and DC bus, whereas scenarios 5 and 6 represented AC and DC loading
conditions on the main busses. Case 4 and 6 examined the transient loading effects on
the AC and DC bus caused by switching AC loads. The HF radio and search radar
loading characteristics were used to represent the transient loads.
The resistive and inductive values used to represent the AC and DC loads for case
2 through 6 are shown in Table 3.2. The numerical panuneter values from Table 3.1
were used to model the AC engine generator. The three-phase AC distribution bus was
modelled fiom three 70-foot lengths of number 4 AWG conductor. The theoretical
resistive and inductive values used to represent this type and length of conductor was
calculated at 0.0 1848 R and 0.02 1 1 mH. The TRU transformer test parameters, as shown
in Table 3.3, were used to model the Wye-Wye and Delta-Wye transfomiers. The load
configuration suxnmary for test cases i through 6 is found in Table 3.4.
During the TRU transformer excitation and short-circuit testing, it was noticed
that the percent excitation current values and core losses were above the predicted values.
Table 3.2 - Simulalion Mode1 AC and DC Load Parameters
1 AC Load Parameters 1 DC Load Parameters 1 Lord
A
B
Load E F
r
Q, A B C A B
R (Q) O. 1429 O. 1667
1
R(R) 5.56
12.80 12.80 39.67 39.67
L (mH) 2.46 5.00 5.00
30.00 30.00
C 1 39.67 30.00 1
Table 3.3 Summary of TRU Transformer Test Parameten
Open-Circuit Data Rated Excitation Da ta Winding Data Freq* S , ~ I - W Lx, L*q,-,, . Voltage (rms) Resistance (R)
400 [Hz] [VA1 [NI [ wl #1 #2,3,4 #1 #2,3,4
i
Y - Y 1 .O5 14.90 47.70 115.00 12.44 0.290 0.00 1 A - Y 1 .O5 10.83 54.30 200.00 12.44 0.225 0.00 1
Short-Circuit Test Data between Windines i & k - - -
Y-Y A - Y i, k 4, [%l 4, [WI 4 . k P l 4, [WI 1 ,2 1.51 7.45 1.33 1 7.86 1,3 1.51 7.45 1.33 7.86 1,4 1.51 7.45 1.33 7.86 2,3 0.24 2.48 1 0.07 2.62 2.4 0.24 2.48 0.07 2.62
Table 3.4 - Mode1 Load Configuration and Test Cases
Caae No. 1 AC Loads 1 DC Loads 1 1- No Load (1 0 amps) 2 1 No Load Load E 3 Load A Load E 4 Load A & Load B Load E . 5 I Load C I Load F 6 Load C & Load D Load F
Phase Load A Load B Load C Load D
S (VA) PF S (VA) PF S (VA) PF S (VA) PF A 3163.5 0.75 376.5 0.88 2232.5 0.73 1296.0 0.96 B 1474.8 0.70 376.5 0.88 2232.5 0.73 - - C 1474.8 0.70 376.5 0.88 2232.5 0.73 -- -
Note: Load A = Essentiai AC Bus Load B = HF Radio Load C = Main AC Bus Load D = Search Radar Load E = Essential DC Bus (1 84.3 amps) Load F = Main DC Bus (1 63.2 amps)
Transformer data provided by Sundstrand Aerospace [32], the OEM for the
TRUs, indicated that the excitation current shodd not exceed 1.2 A for al1 three line
currents, and the three-phase core loss shodd not exceed 43.0 W. As a result of the
discrepancies between the OEM provided data and the laboratory meamred transformer
data as shown in Appendix B, Table B.1, two separate simulation nins were conducted
for each test case. One group of test cases utilized the laboratory-measured data, and the
other group used a 5% excitation cuirent with a three-phase core loss of 43.0 W. This
was done to examine the PF variation and changes in THD levels caused by changing the
TRU transformer percent excitation cunent and core loss values.
The phase voltage, line current, TRU DC output voltage and cunent data obtained
fiom the simulations for each group of cases are found in Table 3.5 - Simulation Mode1
Steady-State and Transient Data, and the corresponding THD data produced by
Harmonic are found in Table 3.6. The ~ i c r o ~ r a n @ input data file developed to simulate
the aimaft electncal power system is attached as Appendix F.
3.4.1 Duration of Simulation
The run-time duration for each test case was directiy proportional to the number
of defined nodes and branches, the run-tirne t,,, and the step width M. The value
assigned to At determines the maximum calculable harmonic number.
One of the objectives of this thesis is to analyze the simuiation mode1 output plot
signais for harmonic content, and determine the THD for each phase voltage and
corresponding branch current. As defined by the Nyquist rate, to measure a specific
hamionic, the number of sarnpling points or the sarnpling rate must be set at a minimum
of twice the harmonic number times the signal fkequency. Hence, to measure and anaiyze
up to the twenty-nfth harmonic, fi@ sample points or fifty iterations are nquired for
each cycle. ui a 400 Hz system, at 2.5 ms per cycle, the step width At, must therefore be
set at a minimum of 50.0 p. The run-the for each test case was set at 0.475s and
Table 3.5 - Simulation Model Steady-State and Transient Data
Note: 1. Case 4 and 6 represent transient studies. The pre- and post- switching (switch-on) values are separated by 'T'.
2. Shaded cells represent 5% TRU transformer excitation current.
3. * Denotes leading power factor.
AC Bus DC Bus Case Phase A V 0 29.4 29.8 -- 26.4 26.7 26.8 27.0
26.8/26.3 27.0/26.5
27.6 27.7
27.6127.1 27.7127.3
Phase B PF 0.98
$0.68 1 0.99 1 .O0 0.86 0,88
0.8610.86 0.881088
0.88 0.89
0.88i0.91 0.89/0.92
Ii (A) 12 (A) 5.2 5.2
1 5.3 5.3
No. . vnm O9 1. (A)
1 1 14.2 3 .O 115J 2.3 ---- -- 18.9
17.4
V b i (V) 1 14.2 115.2 111.5
Phase C V m O U A ) PF
115.6 3 ,O 0.97 115.9 2,4 '0.66
92.4 93.4 94.0 94.6
94,0192.0 94.6/92.6
82.7 83.1
82.7/81.2 83.1181.7
3B
5
109.8 1 12.8 116.1 1 16.5
116.1lI 13.1 1 16.511 13.1
115.0 1 15.7
1 15.011 15.1 1 15.7/116.1
92.4 93.4 94.0 94.6
94.0/92,0 94.6192.6 -
82.7 83.1
82.7/81.2 83.1181.7
M A ) 2.8
1 2.3 19.0
111.5 111.3 1
I I 1.5/108.6 '1 1 lJ/l/109,3
1 14.5 1 14.3
1 14.5/112.4 '1 l W l l 2 , 9
PF 0.97
'0.66 1 P
0.99 19.0 9'17.5p-pp 18.2
30.9 29.0
30.9/32.9 Z9.O/3 1.1
35.2 33.5
35.2135.1 33.5B3.0
43.9 42.0
43.9/46.4 42,01442
35.2 33.2
35.2144.9 33.U43.1
1 .O0 0-89 0.93
0.99 1 .O0 0.90 0.94
0.90/0,90 0.94/0,94
0.89 0.91
0.8910.89 0.91/0.91
1 1 1.8 1 12,4
30.5 28.7
11 1.811 10.5 1 l2.4/llO9
1 15.4 115.1
115.4/111.3 1 K l / l l l . 6
30.5133.2 28.7/3 1.4
35.2 33.1
35.2134.2 33.V32.5
0.89/0.89 0.9310.92
0.89 0.9 1
0.89/0.88 0.91/0.90
required approximately 270 seconds of simulation time to cornpiete using a 100 MHz 486
PC. Each run-time for each test case generated 9500 iterations.
Table 3.6 - Simulation Model Total Harmonie Dhtortion (THD %)
1 Case 1 Voltage 1 Current
Note: Shaded cells represent 5% TRU transformer excitation curent.
3.5 ~ i c r o ~ r a n ~ Harmonic Analysis
The ~ i c r o ~ r a n ~ Harmonic prognun used to evaluate the harmonic characteristics
of the simulation models has been specifically written to analyze results obtained by
~ i c r o ~ r a n ~ output plot files. It cm also be used to analyze data fiom ASCII files as
well. The output binary plot file data are read directly by the harmonic program, and one
cycle of the values are used to calculate the dc component a,,, cosine coefficients ai,
a2 ,..., a,, sine coefficients bi, ba ..., b,,. fiom ( 2 4 , magnitudes Ar. Az ,..., An, fiom (2-3),
phase angles ai, %,. . . , <Dm fiom (2-4). and THD fiom (2-8).
3.6 AVTRON Laboratory Models
The laboratory models were developed to ver@ and validate the simulation
models and resdts. As was done for the simulation model, six test cases were also
devised for the laboratory models. In addition, the laboratory exercise provided valuable
hands-on experience with regard to field measuring equipment set-up and calibration.
This experience was extremely useful in preparation for the on-site abcraft
measuremerits.
Two laboratory model circuit configurations were implemented in the AVTRON
shop at Canadian Forces Base (CFB) Trenton, Ontario. The AVTRON shop is used to
conduct maintenance and electncal parameter performance measurement on aircraft
generators. The AVTRON shop contains an aircraft generator test stand, a three-phase
reactive load bank, and ancillary equipment. The aircraft generator test stand is used as a
prime mover for a generator under test. The expression AVTRON and laboratory are
used synonyrnously throughout this thesis. The first model was designed to represent the
aircrafi essential branch loading and the second model to emulate the main branch
loading. The senes and parallel load parameter values that represent equivalent aircraft
loads as calculated fiom the tabulated remlts of Appendix A, Tables A.1 and A.2, are
shown in Table 3.7. The padlel component parameter values were chosen to represent
the AVTRON laboratory loads because the series component rating requirement for most
of the inductors and resistoa were not readily available fiom open sources.
The AC power source for both models was generated by a 40 kVA 115R00 VAC
400 Hz aircraft generator dnven and controlled by the AVTRON generator test stand and
the M: power was provided by two aircraft TRUs. The AC and DC loads were
constnicted fiom discrete inductors and resistot cornponents. The component load values
used during the AVTRON testhg are show in Figure 3.4. The AVTRON shop reactive
load banks were used to consûuct load C and phase A of load A because these loads, due
to their power ratkg, were not avaiiable h m RMC. Due to the design limitations of the
AVTRON load banks, it was not possible to reproduce the predicted loading requirement
Table 3.7 - AC and DC Theoretical Mode1 Load Parameters
AC Load Parameters I l Series Parallel Configuration Configuration
Na) L (mH) UA) R(Q) 1 (A) L (mH) 1 (A) 1.09 0.36 81.18 1.83 62.84 0.88 52.00
1 1 I 1
DC Load Parameters 1
Load 1 P (W) 1 R(R) 1 1 (A)
Note: Load A = Essential AC Bus Load B = HF Radio Load C = Main AC Bus Load D = Search Radar Load E = Essential DC Bus Load F = Main DC Bus
for phase A of load C. Individuai phase loading adjustments were not possible. Hence,
for load C, the reactive load bank was adjusted to provide an approximate pet phase
loading of 2243.9 VA with a PF of 0.73. Also, the PF and loading requirement for phase
A of load A was not achievable. The largest anainable Ioadiug occurred when the load
was adjusted to provide approximately 4600.0 VA with a PF of 0.85. The lowest
attainable PI: for phase A of load A was 0.77 with a loading of 3 150.0 VA.
VHS Tape Recorder 2OKHz Bandwidth
Loads
A = Essential AC Bus B = HF Radio C = Main AC Bus D = Search Radar E = Essential DC Bus F = Main DC Bus (Nat Showa)
Figure 3.4 - AVTRON Laboratory Mode1
The recorded steady-state and transient data for the AVTRON model is
summarized in Table 3.8 and the correspondhg THD data is found in Table 3.9.
3.6.1 Essential Branch Model
The essential branch model was configured to emulate the essential branch
aircraft Ioading during taxi condition. The aircraft taxi condition loading profile was
denved from the tabulation results of Tables A.1 and A.2 in Appendix A. As shown in
Table 3.4, two AC loads, A and B, and one DC Load E, were used to establish the
essential branch model loading configuration.
Load A represents the essential AC bus three-phase loading profile during taxi
condition and load B represents the HF radio. As shown in Figure 3.4, the AVTRON
laboratory model circuit configuration, al1 AC loads were connected to the AC bus via
three-phase circuit breakers and fused to protect the discrete components from damage in
the event of abnormal failure. The circuit breakers were used as a means of coordinathg
the load configuration and to provide a mechanism for switching the HF radio (load B)
and radar (load D) on and off during the transient analysis phase. Load E, the DC
resistive load, was designed to emulate the essential DC aircraft loading during taxi
condition and constructed fiom seven out of nine available 1.0 Q paralle1 resistive
elements as shown in Annex D, photograph D.4.
3.6.2 Main Branch Model
The main branch mode1 was designed to emulate the main branch aircraft loading
profile during taxi condition. As show in Figure 3.4, Ioads C and D were used to
represent the three-phase main AC bus and single-phase radar load respectively. Load F,
the main branch DC load, was modelled using six 1 .O R parallel resistive elements.
Table 3.8 - AVTRON Laboratory Model Steady-State and Transient Data
DC Bus 1 Case =.
AC Bus Phase A 1 Phase B 1 Phase C
Note: 1. Shaded cells represent transient studies. The pre- and post- switching (switch-on) values are separated by 'T'.
P
2. * Denotes leading power factor.
NO.
1 2
3A 3B
' 4 5 6
VamO 1 1 5.2 1 16.2 1 13.5 1 1 5.2
1 15.4/11$.4 1 16.2
116.411 15.6
WdW 115.1 115.9 1 15.9 1 16.5
1 16.811 16.8 1 16.9
117.111 17.1
I a (A) 2.5 16.3 55.7 42.5
42M46.1 33.0
33.0143.2
PF *0,74 0.99 0.92 0.87
0.87/0.88 0.87
0.87/0.93-
VcnW 1 16.4 1 168 1 17.9 1 18.2
1 18.611 18.6 1 17.3
117.411 17.8
2.8 16.3 26.1 28.0
27.913 1.9 29.3
29.3129.3
PF '0.74 0.99 0.99 0.93
0.9310.94 0.99
0.9910.99
12 (A) 13.0
1 10.0 l
111.0 108.0
104.0/104.0 92.0
92.0192.0 '
Ic(A) 2.6 16.5 26.8 28.5
28.4/322 33.3
33.4133.6
V (V) 29.0 28.1 28.0 28.2
26.9t26.9 28.1
28.2128.2
PF '0.74 0.99 0.97 0.93
0.9110.93 0.85
0.85/0.85
II (A) 10.0 88.0 87.0 91 ,O
89.0189.0 80.0
81.0181.0
Table 3.9 - AVTRON Laboratory Mode1 Total Harmonie Dbtortion (THD %)
3.7 Aircraft Data Acquisition
Electrical îoad measurements on the essential and main busses were conducted on
CF Hercules aircraft CC-130326E at CFB Trenton, Ontario. The aircnft was secured on
a taxiway during load measurements with al1 four engines operating at 100% to simulate
a taxi condition. Ideally, load measurements during flight would have been prefened.
Unfortunately, a long lead-time was required for aircrafk flight triai approval *hrough Air
Command Headquartes in Winnipeg, Manitoba.
Case No.
1 2
3B 4 5 6
An electrical load aircraft checklist, attached as Annex E, luas developed and used
during the aircraft trial data acquisition phase as a guide to identi@ essential and main
bus AC and DC loads. The checklist was divided into two scenarios. The first scenario
identifies AC and DC loads connected to the essential bus, which corresponds to Case
No. 1, 2, 3, and 4. The second aircraf't scenario checklist was developed to identiQ the
main bmch AC and DC loads, and corresponds to Case No. 5 and 6. The aircrafl triai
load configuration is summarized in Table 3.10.
Current
The ideal taxi Ioad condition was not achievable due to numerous operating
restrictions imposed on some loads during the trial. For example, during the essential
branch loading scenario, the propder feather pumps, trim tab actuators, and de-king
Voltage O C
27.40 8.08
@ A 27.60 8.23
@ A 1 Sî
1 . 9 0 2.17
OB 24.80 8.29
5.99 5.98 7.13 8.82
OB 1.55 1.96 3.32
Q C 1.54 1.95 3.26 3.27 2.86 2.78
10.30 10.50 8.03 8-18
2.92 2.76 2.67
9.89 10.10 7.02 6.91
3.35 2.83 2.83
Table 3.10 - Aireraft Trial Load Configuration Summary
Note: 1. Case No. 1,2,3 and 4 represent AC and DC Essentiai Branch Loads.
2. Case No. 5 and 6 represent AC and DC Main Branch Loads.
systems were not switched-on. Sirnilarly, during the main branch loading scenario,
auxiliary and extemal fuel pumps were not switched-on. Two additional scenarios were
conducted to measure the transient response during a main bus to essential bus load
transfer and during an essential bus to main bus load transfer. The bus load transfer
transients were recorded on magnetic media while generator nurnber two and number
three were tripped and their respective loads transfened fiom one bus to the other and
vise versa. The later two scenarios are not part of this thesis work and were conducted
for future work analysis. The data Born scenarios one and two were used to compare and
validate the AVTRON shop and simulation models.
DC Load No Load Full Load Full Load Full Load Full Load Full Load
Case No. 1 2
As s h o w in Appendix D photograph D.8, two tape recorders were setup in the
aircraft cargo area to record steady-state and transient signals on the essential and main
AC and DC busses. One recorder was designated to record al1 signals on the essential
AC and DC busses and the other to record elecüical signals on the main AC and DC bus.
The Dranetz analyzer was comected to the essential bus at the distribution panel in the
cockpit to monitor and record the the-phase generator output AC voltage as s h o w in
Appendix D photograph D.9. The genemtor output currents were monitored on the
cables, which connect the generator to the cockpit distribution panel. These cables were
located in the cargo a r a and secured to the ceihg as shown in Appendix D photograph
D. 10. The DC bus voltage and currents were monitored at the TRU outputs. The DC
AC Load No Load No Load
3 4 5 6
Full Load Full Load & HF Radio
Full Load Full Load & Search Radar
current probes were clamped to each TRU output positive temiinal as shown in
Appendix D photograph D. 1 1.
For each steady-state study, a five-minute recording was obtained. Each transient
recording included one switch-on and one switch-off. While processing the aircrafl trial
data, it was discovered that the AC voltage senson connected on the essential and main
busses were inadvertently reversed. Since only one tape recorder was used during the
recording of individual sceaarios, the following information was Iost: PF for al1 scenarios
and AC voltage data for case 5 and 6. Fomuiately, the AC voltage data for case 1
through 4 was recoverable from the Dranetz analyzer, which was connected to the
essential AC bus at the t h e . The aircrafi recorded steady-state and transient data for the
essential and main bus is summarized in Table 3.1 1, and the corresponding THD line
current data in Table 3.12. The current THD for the aircraft trial, AVTRON model, and
simulation mode1 for test case 4 and 6 is summarïzed in Figures 3.5 and 3.6.
The aircraît trial, AVTRON model, simulation model, and tabulated results from
Appendix A for the essential and main bus loading profile for test case 4 and 6 is
summarized in Table 3.13. The data fiom Table 3.13 is also summarized graphically in
Figures 3.7 to 3.12.
3.8 Instrumentation and Measurements
The instrumentation and support equipment required for both the AVTRON
laboratory testing and on-site aircraft measurements were provided by personnel fiom the
Naval Engineering Test Establishment (NETE), Lasalle, Quebec.
For the majority of the measurements, the he-to-neutral phase voltages and the
corresponding line current including AC and DC waveforms were measured
simuitaneously. The AC and DC currents were measured via high-qudity cunent
probedcunent amp Wers that converted the cunents to low-level voltage signals for the
Table 3.11 - Aircraft Essential and Main Brnnch SteadyState and Transient Data
Note: Shaded cells represent transient studies. The pre- and post- switching (switch-on) values are separated by 'Y'.
Case No.
1 2 3 4 5 . 6 .
AC Bus DC Bus Phase A
,
Phase B 1 Phase C 12(A) 17.9 45.6 44.5
V O ' 29.9 29.6 29.6
PR - - -
Va. O 114.2 114.3 1 34.2
1 4 4 ) 16.9 43.6 42.0 -
- O
Vbm O 1 J 5.3 115.1 1 15.2
U A ) 18.5 43.6 44.8
1 4 / 1 1 4 . - -
1 14.9/114.9 - -
Vcn O 1 14.6 1 14.8 1 14.6
44.6/46,0 13.6
, 13.5/21.2,
Ib(A) 18.1 36.8 35.0
I 14,8/114.8 - O
PF - - -
35,0136.2 12.4
, 12.8112.8
I c (4 18.1 36.8 35.0
.. -
, -
PF - .. -
35.Z36.4 13.1
, 13,3/13.3
43.3/59.3 4
47.4 , 47,4/47.6
39.6/56.3 63 .O
, 63,0165.8
t.
- 29.6 30.9
, - . 30.9
fourteen plus one channel TEAC VHS tape recorders and the voltages were measured via
isolation voltage divider networks and also stored on the tape recorder magnetic media.
The generator phase voltages and phase A line current were continuously monitored
during the testing periods with a Dranetz power quality waveform aoalyzer. The primary
purpose of the analyzer was to capture and store transient waveforms on diskette for
future data anaiysis.
A dual channel Philips dynamic signal analyzer (spectnim analyzer) was used to
observe the hannonic spectnun and total hannonic distortion of the waveforms in real
time, while the wavefoms were being recorded by the tape recorder. The dynamic
analyzer was also used to monitor the recorded waveforms for possible distortion due to
saturation or clipping caused by either incorrect voltage divider tap settings or current
amplification.
For most of the meamrernents, the AC and DC bus voltage and current
waveforms were recorded for a period of one minute so that variations in the waveform
magnitude and THD could be studied more closely.
A Iist and description of the instrumentation and load components used during the
AVTRON laboratory mode1 testing and on-site aircraft rneasurements are outlined in
Appendix C.
Table 3.12 - Aireraft Trial Total Harmonie Dbtortion (THD %)
O A/C Trial O AVTRON
Phase A Phase B Phase C
Figure 3.5 - Essential AC Bus Current THD Summary for Test Case No. 4
Phase A Phase B Phase C
O A/C Trial aAVTRON I Simulation r-
Figure 3.6 - Main AC Bus Current THD Summa y for Test Case No. 6
Tabk 3.13 - Essential and Main Bus Loading Summary for Test Case No. 4 and No. 6 Scenarios
1 Tabulated 1 Ai rcraft 1 AVTRON 1 Simulation I
1 Note: 1. Essential Bus data represents Case No. 4 scenario. I I 2. Main Bus data represents Case No. 6 scenario.
sourceof~ower
Essential AC Bus
Main AC Bus
8
I 3. Unity PF loading assurned for TRU DC tabulated data.
Flight Taxi Trial Mode1 Mode1 2,
Q> A B C A B C
S 11549.18 3661.02 3570.46 7153.07 5692.61 5692.61
Essential DC Bus (A) Main DC Bus (A)
0.83 0.92 0.93 0.90 0.88 0.88
2 1 0.5 199.1
s (VA) 11085.33 3420.33 3328.69 4989.54 3502.15 3502.15
182.4 163.2
PF 0.83 0.91 0.92 0.92 0.90 0.90
11 5.6 1 13.4
s (VA) 5248.60 4159.38 4178.72
- - -
193.0 173.0
PF - - - - - -
185.2 163.4
s (VA) 5319.94 3725.92 3818.92
PF 0.88 0.94 0.93
s (VA) 4831.06 3482.26 3517.41
4993.92 0.93
PF 0.88 0.92 0.94
4865.99 3627.00 3831.30
3431.03 3958.08
0.92 0.90 0.91
0.99 0.85
W Cruise Crax i OAK Trial O AVTRON I Simulation
Phase A Phase B Phase C
Figure 3.7 - Essential AC Bus Loading Summary for Test Case NO. 4
Phase A Phase B Phase C
Cruise
.Taxi
mVTRON
imulation
Figrin 3.8 - Essenail AC Bus Power Factor Summary for Test Case No. 4
m i s e
T a x i
WVTRON
I Simulation
Phase A Phase B Phase C
Figure 3.9 - Main AC Bus Loading Summary for Test Case No. 6
Phase A Phase B Phase C
I Cruise
I Taxi
O AVTRON
I Simulation
Figure 3.10 - Main AC Bus Power Factor Summa y for Test Case No. 6
I Cruise Taxi OAK Triai O AVTRON
Simulation
DC Bus
Figure 3.11 - Essential DC Bus Loading Summary for Test Case No. 4
DC Bus
I Cruise .Taxi O A/C Trial O AVTRON .Simulation
Fipre 3.12 - Main DC BUS Loading Summary for Test Case NO. 6
Chapter 4 Evaluation and Validation
4.1 Introduction
In this chapter, data processing and reduction procedures are discussed, and the
results of the simulation, AVTRON Iaboratory model, and aircraft trial data are
presented. The labontory and aircraft tnd harmonic results are presented as spectral
density plots in dB level format, whereas the simulation harmonic plots are presented in
percent of the fùndamental. The simulation hannonic plot format was chosen because the
discreet harmonic magnitude levels are clearly discemable. The magnitude levels in dB
are easily detemiined fiom the voltage and cunent data provided in Table 3.5. The
results of each case scenario are presented and significant obsewations are discussed.
4.2 Data Processing and Reduction
In this section, the processes used to produce the output data for comparative
analysis are presented. The raw data, which was recorded on magnetic tapes during the
AVTRON model and aircraft trial measurements are presented on various types of output
plots. A sumrnary of the data extracted h m these output plots, such as, voltage, current,
PF, and THD is presented in Tables 3.8, 3.9, 3.1 1, and 3.12. The simulation output data
is presented in Tables 3.5 and 3.6. The various types of output plots used to present the
data for comparative analysis and the equipment used to extract the data and generate
these plots are as follows:
Steady-state AC Voltage and Curtent Plots: Steady-state AC voltage and Iine
cumnt waveforms pertaining to the same phase were plotted to show their
corresponding arnp1itudes and phase relatiomhip. The recorded signais were
exûacted fiom a Philips PM 3375 duai channei digital oscilloscope.
i. Steady-state Fast Fourier Tniisform (FFT) Plots: Steady-state Fast Fourier
Transfonn (FFT) plots were generated to show the frequency component of a
signai for steady-state harmonic content. Each steady-state FFT used a fiequency
span of up to 12.5 kHz and the results of 100 contiguous averages. The
fiindamental fiequency for the AC signals was measured at 400 Hz and the DC
signals at 4.8 kHz. The FFT plots were generated fiom a HP 3561A single
channel dynamic analyzer.
Transient FFT Plots: These types of plots show both the time dornain and
fiequency dornain waveforms. These plots were produced to show the frequency
component of the transient signals. A fiequency span of 20 kHz was used to
measure these signals. It should be noted that the transient FFT plots were
produced when the transient event occuned at the mid-point of the time span
being analyzed.
r Multiple Wnveform Plots: Multiple wavefom plots show a nurnber of signals
simultaneously on a single plot. This type of plot is useW to present an overview
of different signals during a given penodic event. The Astro-Med M9000, a
multiple chamel chart recorder was used to show sirnultaneous signals on a single
plot.
Dranetz Plots: The Dranetz 658 power quality analyzer was used to produce
voltage and line current summaries. Disturbance waveforms captured during the
measurement scenarios were also produced for comparative analysis.
Cascade Plots: A cascade plot is a sequential FFT plot perfomed on a number
of contiguous time segments of the signai. This type of plot is very usefùl to
show the progressive changes in the fiequency domain before, during and after a
transitional event has occurred. The HP 3561A dynamic analyzer was used to
generate cascade plots.
- Simulation Plots: Simulation output plots were produced fiom ~ i c r o ~ r a n @ ' s
MTPlot interactive plotting program. The plotting program produces branch
voltages, line currents, or node voltage plots from binary plot files generated with
the Micro~ran@ transients analysis prognun. Plot files can be produced for thne
domain transient simulations and for fiequency domain steady-state solutions.
Bar charts displaying the harmonic profile and T H . of data signals were
produced fiom the output data generated by ~ i c r o ~ r a n @ ' s harmonic program.
The AVTRON laboratory model and aircrafl trial Cascade and Dranetz Plots are
not presented. They were used to provide data for comparative andysis. A total of 262
plots were generated f?om the AVTRON model measured data and 332 plots fiom the
aircraft triai. Due to the large number of plots generated fiom both surveys, only a few
are presented in this thesis. The AVTRON model and aireraft plots also show the
conespondhg THD. As previously described in section 3.7, while processing the aircrafl
triai data, it was discovered that the AC voltage sensors connected on the essential and
main busses were inadvertently reveaed. As a result, the PF and AC voltage data were
lost. The essential bus AC voltage was recovered fiom the Dranetz analyzer.
4.3 Case No. 1: No Loads
The objective of the fust scenario is to identify the electrical characteristics
imposed by the TRUs as a distinct load on the AC bus during a no AC and no DC Ioading
condition. With the exception of Figures 4.L and 4.2, the simulation plots and
corresponding harmonic profile plots were generated fiom ~ i c r o ~ c a n @ data files using
TRU transformer parameters with 5% excitation cumnt and three-phase iron core loss of
43 Watts. The resulting data derived fiom these plots and the data denved with the OEM
transformer parameters are summarized in Tabies 3.5 and 3.6. The non-highlighted data
ceils in these tables represent the data denved with the T'RU transformer laboratory
measured parameters. These parameters are summarized in Table 3.3.
4.3.1 AVTRON Laboratory and Simulation Results
Figure 4.1 represents the simulated output generator phase A voltage and
conespondhg line current. Although phases B and C are not shown; they also exhibit
similar electrical characteristics with 120 and 240-degree phase shift, respectively. The
simulated generator output phase voltages and line current magnitudes are shown in
Table 3.5. Although a DC load was not applied during this scenario, an average line
current of 2.9 A was measured due to the DC loading produced by the TRU bleeder
resistors. This line current magnitude corresponds with the AVTRON mode1 average
line cunent of 2.6 A. The TRU output DC voltage was measured at 29.4 V and
individual bleeder resistor current at 5.2 A. Figure 4.2 represents the phase A line current
hamionic profile. The THD for this condition was measured at 29.4%.
The simulated voltage and current waveforms show in Figure 4.3 were produced
fiom the same loading condition that produced the wavefoms in Figure 4.1. The data
file for this condition, was modified by changing the TRU transformer excitation current
fiom 14.9% and 10.8% (Y-Y and A-Y transformers) to 5% and the three-phase iron core
loss fiom 143.1 W and 162.9 W to 43.0 W. The PF relationship between Figures 4.1 and
4.3 are clearly shown. In Figure 4.1, the PF was measured at 0.98 lagging and in Figure
4.3 at 0.68 leading.
The effect of reducing the excitation cunent and Von core loss, caused the TRU to
behave as a negative VAR generator. This behaviour is similar to lightly loaded cable
circuits [33]. During this lightly loaded condition, the TRU input shunt filter capacitoa
were dominant During such conditions, negative VARS are produced, causing lagging
PF to decrease as show in Figure 4.3, the bus voltages to increase by an average 0.73 V
and a decrease in line cunent by an average of 0.6 A as show in Table 3.5. This change
also caused an increase in harmonic distortion fiom 29.4% to 36.9% as shown in Figure
4.4 and tabulated in Table 3.6.
Figure 4.5 shows the AVTRON mode1 phase A generator output voltage and
correspondhg line current waveforms. The PF was measured at 0.74 leading. This PF
value corresponds to the value measured for the simulated waveforms show in Figure
4.3. This similarity clearly shows that the simulated TRU PF parameter corresponds to
that of an actual aircraft TRU when the transformer excitation current and core loss
values are set to the recommended OEM values.
Figure 4.6 shows the phase A line current harmonic profile. Al1 AVTRON mode1
and aircrafl trial harmonic plots were generated from the HP 356 1A single channel
dynamic analyzer and displayed in dB level format. To compare harmonic magnitudes
between the dB level format and the simulated percent of fundamental hmonic plots,
the following equation is used:
where
dB = nfh hannonic level (dB)
A,, = nth harmonic voltage or cunent magnitude ( V A ) , and
Ain = input voltage or current magnitude ( HA).
For example, to calculate the 1 1 " harmonic magnitude in Figure 4.6, one would find the
antiiog ofA, from (4.1). Re-arranging equation (4.1):
where the input current magnitude, Ain , is 300.0 pl, and the 11" hmonic dB level is
measured at 59.0 dB. Hence, the 1 lth harmonic magnitude is 0.27 A and the percentage
of the fûndamental is 1 1 .O%.
Figure 4.6 shows the AVTRON model curent harmonic profile. The siwcant
harmonics are al1 odd nurnbered. As indicated in section 2.3, static power converters
such as the T'RU, cm be viewed as harmonic generators due to their cyclic or current rd th th th chopping action. The dominant odd hannonics are the 3 , 5 ,7 ,9 , 1 1". 13", and 19".
Although the 15" and 17" harmonics are clearly visible, their magnitudes are minimal. It
sufices to Say that the hannonics produced by the TRU (the commutated converter) is
related to the pulse nurnber of the device. The aircrafi TRU is a twelve-pulse converter
and generates major characteristic harmonic currents of order 1 2 x n f 1. This
mathematical expression is representative of the harmonic profile produced by the
AVTRON model as shown in Figure 4.6 and to a lesser degree by the simulated model as
show in Figure 4.4.
Phase A Current THD = 29.4% 25 -
Hamonic No.
T l r -18: m-1) S. m c k -
Figure 4.1 - Case I : VA & IA Wavefomis Figure 4.2 - Case 1 : IA Harmonic Profile
Figure 4.3 - Case 1 : VA & IA Waveforms Figure 4.4 - Case 1 : IA Harmonic Profile
"5% TRU Transformer 1,;' "5% TRU Transformer I,,;'
v Time Gale: O.Sms/DiV UA 1
SlrC1T: O HZ BY: L19.M HZ STOP! 12 500 HZ X: 4n6.28 Ht K 4 & THO. 27.6 t
Figure 4.5 - Case 1 : VA & k Waveforms Figure 4.6 - Case 1 : IA Harmonic Profile
"AVTRON Laboratory Model" "AVTRON Laboratory Model"
4.4 Case No. 2: Essential Branch - DC Load The second scenario was devised to emulate the aircraft essential bus DC loaduig
during a taxi condition. The DC load magnitude as shown in Table A.8 was tabdated at
182.4 A. Two assurnptions were used to determine the essential taxi load. The first
assumption, that al1 DC loads identified in Table A.8 are switched-on during the aucraft
taxi profile. Secondly, the TRU DC output voltage remains constant at 28.0 V.
As shown in Figure 3.4, the DC essentiai lod, identifîed as Load E, was used to
represent both the simulation model and the AVTRON model DC loads. The AVTRON
rnodel DC load was designed from seven 1.0 R, 1.0 kW resistive elements. These
resistive elements were al1 connected in parallel to produce a 0.1428 R load. This load is
shown in Appendk D, photograph D.4. A TRU DC output voltage of 28.0 V will
produce a current magnitude of 196.1 A with a 0.1428 Q resistive Ioad. Although, this
amperage is slightly greater (13.7 A) than the tabulated value, it is assumed to be
acceptable (within 7.5%) for simulation and rnodelling purposes.
A significant change was made to the input data file following the initial
simulation nui. Uaexpectedly, the AC generator bus voltage dropped fiom an average
1 14.7 V (Case 1) to approximately 11 0.0 V. To compensate for this effect, the generator
peak output terminal voltage data field was increased to 172.6 V. For obvious reasons,
this situation represents a significant compromise with respect to modelling the engine
generator. Additional research work is required to identiQ the cause, and to develop a
suitable solution.
4.4.1 AVTRON Laboratory and Simulation Results
Figures 4.7 and 4.1 0 show the simulated and AVTRON model phase A bus
voltage and corresponding line cunent, respectively. Both wavefoms show a PF value
of 0.99 and sunilar graphical characteristics. The PF observation demonstrates that the
TRU emulates a resistive load during moderate loading conditions. As shown in Tables
3.5 and 3.8, the line currents are similar in magnitude. The AVTRON mode1 line cunent
was measured at 16.4 A and the simulation at 17.7 A. The average AC bus voltage for
the AVTRON model was measured at 116.3 V and for the simulation at 11 1.8 V.
Although the simulation phase voltage levels were much lower, increasing the generator
terminal peak voltage level fiom 1 72.6 V to some unknown delta value could have raised
the bus voltage. To minimize the non-productive t h e required to compile the
simulations, this work was not done. The primary objective of the simulation is to
explore its ability to reproduce measurable data fiom a real model, not to fudge data
parameters to achieve an end remit.
Figures 4.8 and 4.9 show the simulated voltage and line current harmonic profile
generated fiom Figure 4.7 waveforms. Figures 4.1 1 and 4.12 show the AVTRON model
voltage and iine current harmonic profile generated fiom Figure 4.1 0 wave forms. The
simuiated voltage THD was measured at 6.9% and the current at 13.1 %. The AVTRON
model voltage THD was measured at 1.9% and the corresponding line current at 8.29%.
The significant decrease in THD levels fiom Case 1 to Case 2 is due to the TRU loading
characteristics. In Case 1, the TRU load, as seen fiom the generator terminais, is
equivalent to a capacitive load, and in Case 2, a resistive load.
Figure 4.7 - Case 2: VA & IA Waveforms
f hase A Voltage THD = 6.9% Phase A Current THD = 13.14% 7 , 12
Hannonic No. I ; Harmonic No.
Figure 4.8 - Case 2: VA Harmonic Profile Figure 4.9 - Case 2: k Harmonic Profile
As show in the AVTRON laboratory model hannonic plots, the 13" harmonic is
dominant, whereas in the simulation plots, the 1 1" harmonic is greater in magnitude. The
131h harmonic current magnitude for the AVTRON model was measured at 0.66% of the
fundamental, and the voltage at 2.15%. However, the overall harmonic profile
characteristics between both series of plots are similar.
Figure 4.10 - Case 2: VA & IA Wavefonns
"AVTRON Laboratory Modei"
Figure 4.1 1 - Case 2: VA Harmonic Profile Figure 4.12 - Case 2: IA Hannonic Profile
"AVTRON Laboratory Modei" "AVTRON Laboratory Model"
4.5 Case No. 3: Essential Branch - AC and DC Loads
The third scenario was devised to emulate the aircraft's AC and DC essentiai bus
loading profile during pre-flight taxi conditions. For this scenario, three single-phase AC
reactive loads were designed to represent the three-phase load. This load is identified as
load A in Figure 3.4; the AVTRON laboratory model configuration. The DC resistive
load used to represent the essential load in Case 2, is also used for this scenario. Note
that the load component d u e s identified in Figure 3.4, were also used to develop the
simulation modei.
As shown in Table 3.7, the theoretical three-phase AC loading requirement to
estabiish the essential load was tabuiated from Tables A. 1 and A.2. The AVTRON shop
reactive load bank was used to constnict phase A of load A. Phases B and C were
constmcted from discreet inductor and resistor components supplied fiom the RMC
power laboratory. A 5 kW resistive load bank adjusted to provide 12.8 R was used to
constmct the resistive elements. The inducton were constnicted by connecting two
10 mH inductors in parallel to produce 5 mH inductors. Although these component
values are not an exact theoretical representation of phase B (R = 12.16 R, L = 4.25 mH)
and phase C (R = 12.930, L = 4.52 mH) requirements, they are assumed to be close
enough for modelling purposes.
During the AVTRON model set-up, it was discovered that the AVTRON shop
reactive load bank was not capable of providing the phase A PF and theoretical (kVA)
loading requirement. The maximum attainable loading occurred when the load was
adjusted to provide approximately 4600.0 VA. Beyond this value, a protection circuit
breaker wouid open. At this setting, the PF was measured at 0.85. The recorded model
data for this load condition is show in Table 3.8 as Case 3A. The load bank was then
adjusted to provide a conrinuous PF of 0.77, the theoreticai value, while the load was
increased until the circuit breaker opened. At this setting, the loading was rneasured at
3 150.0 VA. The recorded data for this loading profile is shown in Table 3.8 as Case 3B.
4.5.1 AVTRON Laboratory and Simulation Results
Figures 4.13 to 4.24 were produced to show the simulated three-phase sinusoidd
AC voltage and line current waveform characteristics and their corresponding harmonic
profiles. Analysis of the simulation data following the initial simulation nui, identified a
significant voltage drop on the AC bus. To compensate for this situation, the generator
output terminal voltage data field value was increased From 172.6 V (Case 2) to 184.6 V.
The resulting data derived from the simulation is shown in Tables 3.5 and 3.6.
The three-phase PF and line current data measurements derived from the
simulation are very similar to the AVTRON model data for Case 3B as shown in Tables
3.5 and 3.8. The complex power loading for each phase was measured and compared.
For phase A, the complex power was measured at 4896.0 VA, with a lagging 29.5 degree
phase shift, phase B at 3262.0 VA, with a lagging 2 1.6 degree phase shift, and phase C at
3368.7 VA, with the same phase shifi as for phase B. It is interesting to note, that the
generator output phase voltages varied fiom 1 15.2 V for phase A to 1 18.2 V for phase B.
This represents a 3.0 V phase differential. The simulation model also produced similar
results, with a 5.2 V phase differential between phase A and C. The loading
characteristics of this AC load represents a classical example of an unbalanced load.
Unbalanced loads cm produce severe electncal perturbations on power systems.
Examples of these perturbations are: heating in machines and Ioads, increased Tm,
phase voltage and current unbalances, and subsynchronous resonance.
With respect to harmonic distortion measurements, the T H . level between the
simulation and AVTRON model varied by as much as 126% for phase B line current.
The simuiated phase voltage THD levels exceeded the AVTRON model levels by as
much as 187%. Possible causes for this discrepancy couid be attributable to the TRU
model andfor engine generator model. Further work is required to identiQ enhancement
measures, which will improve the harmonic characteristics of the simulation model. This
work is beyond the scope of this paper. However, the THD pattern between the
simulation and AVTRON model is similar. For exarnple, the THD level for both phase A
voltage and line current is significantly less than phase B and C levels. This leads to
another observation. As reactive loads increase, THD levels decrease.
Figure 4.25 was presented to show the AVTRON model phase A voltage and
current waveforms. Figures 4.26 and 4.27 represents the voltage and current harmonic
profile generated fkom figure 4.25 waveforms. Note that the 1 1" and 13" harmonic are
dominant for the current wavefonn with a 0.42% of the fundamentai, and the dominant
harmonic for the voltage waveform is the 2 lSL, with a 1 .O% of the fundamental. The THD
levels for phase A voltage and line current were measured at 2.17% and 5.99%,
respectively. The three phase voltage and line current THD Ievels are shown in
Table 3.9.
As show in Table 3.5, the sirntdated DC voltage was measured at 27.0 V and the
load current at 188.0 A. The AVTRON model TRU DC output voltage was measured at
28.2 V and the load current at 199.0 A. It is interesting to note, that a differential TRU
output current of 27.5 percent was measured between the two TRUs for Case 3A, as
shown in Table 3.8.
Figure 4.13 - Case 3 : VA Waveform F igw 4.14 - Case 3 : VA Hannonic Profile
2.-
k.W.
. m#ra I u ILPI-. &lm -3 I
I n i a r
Phase A Voltage THD = 4.1% 4
3.5 . ; "s.
#.a
, . , .
9
. . .k .' m . ,' -7 3.œ
V I 1 1 I
2 4 6 8 10 Hamonic 12 14 No. 16 18 20 22 24
ira 3.a . 9 i l l 3.s~ 3 .n 1.k 1
t h mœk: UI(-11 a. ,-II.
Figure 4.15 - Case 3: VB Wavefonn
Figure 4.17 - Case 3: Vc Wavefom
llRlR- Quran.. bli: L)r(l) (0
: m m . .
1
l Phase B VoItage THD = 4.5% I
2 4 6 8 10 12 14 16 18 20 22 24
Harmonic No.
Figure 4.16 - Case 3: Vs Harmonic Profile
Phase C Voltage THD = 4.5%
2 4 6 8 10 12 14 16 18 20 22 24
Harmonic No. - - -..
Figure 4.1 8 - Case 3 : Vc Harmonic Profile
Phase A Current THD = 2.6% ' 2 5
2 4 6 8 10 12 14 16 18 20 22 24
Harmonic No.
t tr =let Urc-U S. 9-l.
Figure 4.1 9 - Case 3 : IA Wavefonn Figure 4.20 - Case 3: IA Harmonic Profile
Phase B Current THD = 4.8% 4
Figure 4.2 1 - Case 3 : Ie Waveform
r t u mm w-1) S. 0--
Figure 4.23 - Case 3: Ic Waveform
2 4 6 8 10 12 14 16 18 20 22 24
Hmonic No. - -- - - -
Figure 4.22 - Case 3: Ie Hamonic Profile
,- --
Phase C Current THD = 5.3% 5 -
Harmonic No.
Figure 4.24 - Case 3 : Ic Harmonic Profile
Figure 425 - Case 3: VA & IA Wavefom
"AVTRON Labonitory Model"
Figure 4.26 - Case 3: VA Hamionic Profile c 406.28 m r: 42.09 *ru rtO: 5.W %
Figure 4.27 - Case 3 : lA Harmonic Profile
"AVTRON Laboratory Model" "AVTRON Laboratory Model"
4.6 Case No. 4: Essential Branch - AC Transient and
DC Loads
Case 4 was devised to emulate the AC and DC essential bus loading as in Case 3,
with the addition of a three-phase switchhg load. The motivational factor for
implementing this scenmio, is to explore the waveform transient characteristics imposed
by switching a three-phase Ioad on and off on the AC bus.
During the simulation m, the load was switched-on at 0.3s and switched-off at
0.4s. This was accomplished with the use of the-controlled switches and setting a
current margin of 4.5 A. The switch closes at the tirne step closest to Taose and opens
again after the t h e step closest to Topm. either as soon as the switch current ISwFTCH has
gone tbrough zero or as soon as the magnitude of IswmH has become less than the
current margin. For the AVTRON model set-up, the load was switched-on and off with
the use of a three-phase circuit breaker.
The switching load represents the HF radio and identified as load B in Figure 3.4.
A 14channel T 'Ac VHS tape recorder was used to capture on magnetic media the
AVTRON model AC voltage and line curent waveforms during the transient event. As
shown in Appendix A, Table A.3, the HF radio is rated at 370.4 VA per phase with a PF
of 0.90. This load ratine represents an average operating power of 1.0 kW. Three
30.0 mH inductors and three 50.0 Q variable resistors adjusted to provide 39.7 R per
phase were used to construct the AVTRON HF radio load. This load is s h o w in
Appendix D, photograph D.6. These component values are within 7.9% of the theoretical
values required to represent the HF radio as a reactive load. It is important to mention
that during the analysis of the aircmft DC current plots, during the switch-on of the HF
radio, the output cunent fiom both TRUs increased to signincant levels. This
observation indicated that the HF radio not only requires an AC source, but a DC source
as well. Unfortunately, the HF radio DC component loading requirement was not
icientified during the preliminary theoretical design process. As such, the HF radio DC
load component was not simulated.
4.6.1 AVTRON Laboratory and Simulation Results
Figure 4.28 shows the simulated phase A voltage and current wavefoms during
the three-phase transient load switch-on event at 0.3s. Analysis of these waveforms does
not show any indication of transients during the switch-on. Figures 4.29 and 4.30
represent the corresponding voltage and current harmonic profiles. The voltage
magnitude decreased an average of 2.3 V following the switch-on of' the Ioad, and the
line current magnitude increased an average of 2.3 A pet phase. Once agaln, the 1 1" and
1 3 ~ harmonies for both waveforms are dominant. The cunent hamonic plot of
Figure 4.30 does show an increased level fiom previous plots for the 3rd and 5" harmonic
during this event. Phases B and C were not shown because indications of transients on
these waveforms were not observed.
Figures 4.3 1 and 4.32 show the phase A voltage and current waveforms and
conesponding transient FFT harmonic plots recorded fiom the AVTRON mode1 during
the the-phase load switch-on. Similar to the simulation results, significant transients
were not recorded. However, the voltage wavefonn does show a very small distortion on
the positive crest of one of the sinusoids. The voltage magnitude before and d e r the
switch-on remained constant. The voltage harmonic pattern appears to be similar to that
of the simulation voltage hannonic profile up to and including the 2sLb hannonic. The
current harmonic pattern appears to be simiiar to the simulation current harmonic profile
up to and including the 15" hmonic.
The switch-off voltage and current waveforms were not shown because
significant transients were not recorded fiom either the simulation or the AVTRON
model duriog this event. The phase A, B, and C measured data for both the simulation
and AVTRON model are presented in Tables 3.5 and 3.8, respectively, and the THD
levels for both models are presented in Tables 3.6 and 3.9. The THD level for the
simulation voltage and current waveforms is approximately 140% greater and 50% less
than the AVTRON model waveforms, respectively.
In Figure 4.33, the phase A voltage harmonics (1 l", 13", 23rd, and 25") derived
from the simulation and AVTRON models were compared with the maximum acceptable
harmonic levels as defmed in MIL-STD 704E. These maximum harmonic levels (% of
fundamental) were derived fkom the maximum distortion spectrum of AC voltage plot
[22]. This plot quantifies AC voltage distortion in ternis of the amplitude of each
frequency component. With the exception of the 1 I" hamionic, which was denved from
the simulation model, al1 test Case 4 harmonic levels complied with MIL-STD 704E.
tim tule: lû-(-11 S. m n ~ e d w ~ ~ w u .
Figure 4.28 - Case 4: VA & IA Waveforms
Phase A Voltage THD = 4.1% Phase A Current THD = 2.7% 2.5
2 4 6 8 10 12 14 16 18 20 22 24
Hannonic No.
2 4 6 8 10 12 14 16 18 20 22 24
Harmonic No.
Figure 4.29 - Case 4: VA Harmonic Profile
Figure 4.3 1 - Case 4: VA Wavefom &
Harmonic Profile
Figure 4.30 - Case 4: LA Harrnonic Profile
StUlT. O via Bw: 1- 47 nr STOP' NI 900 HZ LI: WCCC [RI
1
Figure 4.32 - Case 4: IA Waveform &
Harmonic Profile
Simulation AVTRON MIL-STD 704E
Figure 4.33 - Phase A Voltage Harmonic Summary for Test Case No. 4
4.7 Case No. 5: Main Branch - AC and DC Loads
Case 5 was devised to emulate the aircraft main AC and DC pre-flight taxi load
condition as tabulated in Appendix A, Tables A.5 and A.10. The AC and DC AVTRON
model, and simulation model load configuration and values are shown in Figure 3.4 and
identified as load C, and load F, respectively. For this scenario, the AVTRON load bank
was used to provide the loading requirement to reproduce the three-phase AC reactive
load.
Discreet components required to construct the AC load were not available From
RMC because of the power dissipation requirement as s h o w in Table A.1. As
previously described, the AVTRON load bank does not have the capability for
independent phase loading and PF adjustments. As a resuit, the three-phase load for this
scenario is treated as a balanced load. The load bank controls were adjusted to provide
an approximate per phase loading of 2245.0 VA with a PF of 0.73. This loading
compared to the tabuiated per phase results of Appendix A, Table AS, represents a
discrepancy of 38.2% for phase A, and 0.5% for phase B and C.
The DC resistive load was consûucted fiom six 1.0 0, 1.0 kW resistive elements.
These resistive elements were connected in parallel to produce a 0.1667 Q load. This
resistive load will produce 168.0 A at 28.0 V. Although this amperage is slightly greater
(4.9 A) than the tabulated value, it is assumed to be acceptable (within 3.0%) for
simulation and modelling purposes.
4.7.1 AVTRON Laboratory and Simulation Results
Figures 4.34 and 4.37 represent the shulated and AVTRON model phase A main
bus voltage and correspondhg iine curent, respectively. As shown in Table 3.5, the
simulated model phase A PF was measured at 0.89 and phases B and C at 0.91. This
observation uidicates that the TRU Y-Y and A-Y trilIlSformers are not lineariy balanced.
For exampie, the impedance as seen Iooking into the Y-Y transformer circuit is not equd
to the input impedance of the A-Y transformer. As shown in Table 3.8, the AVTRON
model phase A PF was measured at 0.87 and phase B at 0.99, and for phase C at 0.85. It
is interesthg to note that the AVTRON load bank did not provide a balanced three-phase
load. This observation demonstrates that the reactive load component for phase B was
not connected. A PF of 1 .O (z 0.99) represents a resistive load.
The voltage and line current THD levels for the simulation and AVTRON models
are shown in Tables 3.6 and 3.9. Figures 4.35 and 4.36 represent the phase A voltage and
line current harmonic profile for the simulation model, and Figures 4.38 and 4.39
represent the phase A voltage and line current harmonic profile for the AVTRON model.
In these plots, the 11" and 13' harmonies are dominant as expected.
As shown in Table 3.5, the average three-phase line current was measured at
33.3 A. The average phase A and C current for the AVTRON mode1 were rneasured at
33.2 A, and for phase B line current at 29.3 A. The lower than expected current value for
phase B is attributable to either an electricai or mechanical deficiency with the AVTRON
phase B load bank.
Figure 4.34 - Case 5: VA & L Waveforms
Phase A Voltage THD = 4.1% 4 .
Phase A Current THD = 3.9%
Hamonic No. Harmonic No. --
Figure 4.35 - Case 5: VA Harmonie Profile Figure 4.36 - Case 5: [A H m o n i c Profile
Figure 4.37 - Case 5: VA & IA Waveforms
"AVTRON Laboratory Model"
I - L S T ~ . O nx nY: 1is.aa )rX m m 12 aoo nr' s r m o nz BY: ;sm.)s nz ww. 12 300 H A. 46 .as IL c ~13.1 SPU w 2.76 x x 40a.m 9: 33 ta rrmi ry): .r 13 1
Figure 4.38 - Case 5: VA Harmonic Profile Figure 4.39 - Case 5: L Harmonic Profile
"AVTRON Laboratory Model" "AVTRON Laboratory Model"
4.8 Case No. 6: Main Branch - AC Transient and DC
Loads
The fuial scenario was developed to emulate the AC and DC main bus loading as
in Case 5, with the addition of a single-phase switching load. As shown in Figure 3.4, the
single-phase load is identified as load D, and represents the reactive loading for the
aircraft search radar. The motivational factor for implernenting this scenario is to explore
the waveform transient characteristics imposed by switching a single-phase load on and
off on the AC bus.
Durùig the simulation nui, the single-phase load was switchedsn at 0.3s and
switched-off at 0.4s. The theoretical component representation for this load is s h o w in
Table 3.7, where the inductor value was calculated at 14.46 mH and the parallel resistor
at 10.6 S2. As shown in Appendix A, Table AS, the search radar is rated at 1300 VA
with a PF of 0.96. The reactive load was constnicted wiîh two senes comected (10.0 &
5.0 mH) inductors and two series connected variable resistors (8.0 & 3.0 R) adjusted to
provide 10.6 R. This load is shown in Appendix D, photogtaph D.7. These components
are witbin 3.7% of the theoretical values.
During the analysis of the aireraft DC plots, the TRU output current waveforms
showed an increase in current durhg the switch-on penod. This observation indicates
that the search radar requires a DC source to operate. Unfomuiately, the search radar DC
component loading requirement was not identified during the preliminary theoretical
design process and as such was not modelled or simulated.
4.8.1 AVTRON Laboratory and Simulstion Results
Figure 4.40 represents the simulated phase A voltage and current wavefoms
duing the single-phase load switch-on event at 0.3s. Analysis of these waveforms does
not show significant transients during the switch-on. However, a slight voltage distortion
is s h o w on the positive crest of the 0.3s sinusoid. Figures 4.41 and 4.42 represent the
corresponding voltage and current hamonic profiles. As s h o w in these plots, the Il'
and 13" hannonics are dominant. Phase A and B voltage levels decreased by 1.4 and
3.5 V, respectively, following the switch-on. Phase C voltage increased by 0.4 V.
Figures 4.43 and 4.44 show the AVTRON model voltage and current waveforrns
and corresponding harmonic profiles during the switch-on event. The centre voltage
sinusoid representing the time of switch-on shows a srnail distortion on the positive crest,
similar to the simulation remlts. Both harmonic plots clearly show the dominant 1 1" and
13" harmonics. In the current harmonic plot of Figure 4.44, the 17" and 19" pair, and
the 23* and 25" pair of odd harmonics are clearly identifiable. The voltage and line
current THD leveis recorded for the simulation and AVTRON models are show in
Tables 3.6 and 3.9, respectively. The phase A voltage level recorded a decrease of 0.8 V
and an increase in line current of 10.2 A following the switchsn event, which is
comparable to the simulation results.
As shown in Figure 4.45, the phase A voltage harmonics derived from the
AVTRON rnodel, and the 13", 23d, and 25' harmonics fiorn the simulation model
complies with MIL-STD 704E. The 11" harmonic denved h m the simulation model
exceeds MIL-STD 704E requirement by 0.4%.
T i r scale: 19-C-1) S. nu~dbrn. nu.
Figure 4.40 - Case 6: VA & la Waveforms
Phase A Voltage THD = 3.6% Phase A Current THD = 2.2% 3.5 : 2 7
I
Hmonic No. , Hmonic No. 1 1
Figure 4.41 - Case 6: VA Harmonic Profile Figure 4.42 - Case 6: IA Harmonic Profile
'"in 10 dB
/DIV
20 mv
START: O Hz BU: i90.97 Hz STOP: 20 000 HI B: BUFFC (RI
START: 254.79 msec STOP: 274.79 mSm X: 400 Hz V: iiCI.4 Vrma T 2.67 X
Figure 4.43 - Case 6: VA Wavefom & Hmonic Profile
"AVTRON Laboratory Model"
A
5 0 dB
/DIV
4 fnA
START: O HZ BU: 190.97 HZ STOR 20 000 Hl 8: BUFFC CR)
BO 4
A
20 A
/DIV
i I
Figure 4.44 - Case 6: IA Waveform & Hamonic Profile
"AVTRON Laboratory Modei"
Simulation AVTRON MIL-STD 704E
Figure 4.45 - Phase A Voltage Hmonic Summary for Test Case No. 6
For both the simulation and AVTRON model, phase A PF variation before the
switch-on event was measured at 0.89 and 0.87, and after the event at 0.92 and 0.93,
respectively. These PF values represent 2.2% of the expected theoreticai resdts.
Significant voltage or current waveform transients fiom both the simulation and
AVTRON models were not observed during the switch-off event, as a result, these plots
were not shown.
Figures 4.46 and 4.47 represent the simulated phase A voltage and line current
cascade harmonic plots. These plots show the THD Ievels for three distinct consecutive
2.5 ms periodic cycles starting at 0.39, the switch-on event. As show in both plots, the
switch-on cycle (0.3s) generates the greatest THD, as expected.
Phase A Voltage
- - . - - 0.3000 sec THD 4.3% - - - - 0.3025 sec THD 3.9% - 0.3050 sec 'MD 3.8%
2 4 6 8 10 72 14 16 18 20 22 24
Hannonic No.
Figure 4.46 - Case 6: VA Cascade Harmonic Profile
I Phase A Current I
I - - A - - 0.3000 sac THO 4.9% - - - - 0.3025 w THO 2.3% - 0.3050 sec THD 2.3%
I
2 4 6 8 10 12 14 16 78 20 22 24
Harmonic No.
Figure 4.47 - Case 6: IA Cascade Harmonic Profile
4.9 Aircraft Trial Results
Electrical load rneasurernents were conducted on a CF Hercules aircraft at CFB
Trenton, Ontario. The aircraft was secured on a taxiway with ail four engines operating
while the loads on the aircraft were adjusted to achieve various loading conditions. Eight
test case scenarios were developed to exercise theses loading conditions on the AC and
DC essential and main bus. Oniy six test case scenarios are presented. The two scenarios
not presented were conducted to measure the transient response during a main bus to
essential bus load transfer and during an essential bus to main bus load transfer. These
two scenarios were conducted for fùtwe work analysis. Due to the large number of plots
generated fiom the airc raft trial, on1 y signi ficant observations are discussed.
As show in Table 3.1 1 , Cases 1 to 4, represent electrical data acquired from the
essential AC and DC bus, and Case No. 5 and No. 6 represent recorded data frorn the
main AC and DC Bus. Cases 4 and 6 represent transient studies conducted by switching
on and off, a three-phase load on the essential branch and a single-phase load on the main
branch. A summary of the loading conditions for each test case is shown in Table 3.10.
While processing the aircraft triai data, as described in section 3.7, the AC voltage
sensors connected on the essential and main busses were inadvertently reversed. As a
result, the AC voltage data required to determine the PF for dl scenarios was Lost. The
AC phase voltages shown in Table 3.1 1 were recovered fiom the Dranetz analyzer, which
was c o ~ e c t e d to the essentiai bus during the trial. AC Voltage waveforms are not
presented because the voltages for case 1 to 4 were not recorded on magnetic tape.
During the trial, an equipment load checklist, attached as Appendix E, was used to
identa the equipment operating status for each test case. Unfomuiately, the anticipated
loading condition for al1 test cases was not achievable due to numerous restrictions
imposed on some loads during the trial. For example, for case No. 1 and No. 2, the fuel
boost pump No. 2 and hydraulic auxiliary pump could not be turned off during the entire
triai. Restrictions were also imposed on heat sensitive DC loads and fuel pumps.
As shown in Table 3.1 1, the AC phase loading for Case 1 and 2 was much greater
than predicted, and the conesponding DC loading was much less. This discrepancy was
attributable to restrictions imposed on certain loads. Similady, for Cases 5 and 6, the
loading profile was much less than expected. The optimum loading profile was achieved
for test Case 3. During this scenario most of the AC and DC loads were switched-on. A
phase unbalance of 1105.2 VA was measured between phases A and C. As defined by
MIL-STD-704E [22], the maximum acceptable load unbaiance for Case 3 is 683.3 VA.
This situation represents an unbalanced condition that exceeds the allowable limit by
421.9 VA. The chart used to determine the unbalance load lirnits for a three-phase
system is show in Figure 4.48. The unbalanced loading profile for Cases 1 to 4 is
summarized in Table 4.1. The unbalanced loading profile for the essentid and mûin AC
bus for test Case 4 and 6 is summarized graphically in Figures 4.49 and 4.50.
It is important to mention that Military Standard 704 is a standard adopted to
ensure compatibility between the aircraft electric system, extemal power, and airborne
utilization equipment. This standard defines the requirements and describes the
characteristics of aircrafl electric power provided at the input terminais of electric
utilization equipment.
Figure 4.51 shows the main bus phase B current wavefonn and corresponding
harmonic profile. The THD was rneasured at 10.1 % and the line current at 12.4 A. This
data is also presented in Tables 3.1 1 and 3.12. As expected, the THD values on the main
bus were higher then the THD values on the essential bus. Two primary conditions can
cause THD values to change. The nrst, assuming that the AC loading remains constant,
is that as the DC load ïncreases, the THD on the AC side will increase due to current
commutation. Secondly, assuming that the DC loading remah constant, as the AC load
inmases, the THD on the AC side will decrease due to hmnonic absorption. The
loading condition on the main branch is such that the DC loading is higher than the
essential DC load, and the AC loading is less than the essential AC loads. The harmonie
plot clearly shows the harmonic characteristics of a 12 pulse iine commutated device. As
expected, the 1 1" and 13" harmonies are dominant.
Table 4.1 - Aircraft Essential AC Bus Load Profile
I . -. .
Note: * represents (VA) which exceeds MIL-STD-704E unbalance limits
Figure 4-48 - Load Unbalance Limits for Three-Phase Systems
L
Case No.
1 2 3 4
Total 3 0 Load S (kVA)
6.274 13.444 13.159 13 .587
Exceeds Load Limit s VA) -428-7 "67.3
$42 1.7 "393.2
Load Unbalance
s (VA) 38.4
758.8 1105.2 1089.2
Max Load Unbalance s (VA) 466.7 691.7 683.3 695.8
Unbalance n
Figure 4.49 - Essential AC Bus Unbalance Loading Summary for Test Case No. 4
Cruise Taxi AVTRON Simulation
Figure 4.50 - Main AC Bus Unbalance Loading Summary for Test Case No. 6
20 A
1 O dB
/DfV
2 mA
ST ART: I
O HZ BW: 119.36 HZ STOP: 12 500 Hi 4 t
0: T IME (RI 40 A
10 A
/orv
-40 1 1 START: O Sac STOP: 32 mSec X: 406.25 HZ Y: 12.41 Arma THO: 10.1 X
Figure 4.51 - Case 5: Main AC Bus - IB Waveform & Harmonic Profile
"Aircraf't Trial"
Figure 4.52 represents the phase A current waveform during the search radar
switch-on event and associated hannonic profile plot. The waveform shows a single
cycle surge with a peak amplitude of 29.7 A. A swge of this magnitude does not
represent a significant transient. The pre and post switch-on current were measured at
13.5 A and 21.2 A, respectively. Although the search radar is rated at 1300 VA with a
power factor of 0.96, which represents a steady-state current of 11.3 A, the radar load
current was measured at 7.7 A. This discrepancy is attributable to the fact that the radar
was operating in low power mode during the trial.
rd th th The harmonic profile shows that the 3 , 5 , 7 , and 19' harmonics arerelatively
the same magnitude as the 1 1' and 13" harmonics. The harmonics were generated fiom
a sampling rate of 2.56 times the fiequency span of 20 kHz The harmonic bandwidth
was set at 50 Hz for al1 transient studies.
A
1 O dB
/DIV
3 mA
STAR^: O Hz BW: 50 HZ STOP: 20 000 HZ
Figure 4.52 - Case 6: Main AC Bus - L Wavefom & Harmonic Profile
-80
" Aircrafi Trial: Search Radar S witch-On"
1
Figures 4.53, 4.54, and 4.55 waveforms represent the essential bus DC voltage
START: 296.99 mSec STOP: 316.99 mSsc X: 400 Hz Y: 21.04 Arms TM: 4 - 1 9 X
and output cunents fiom TRU No. 1 and 2, respectively. These waveforms and
associated harmonic plots are shown to illustrate the harmonic characteristics, which can
be extracted fiom these types of plots. As previously described, the harmonic profile is
nothing more than a frequency representation of a signal in the t h e domain.
As s h o w in Figure 4.53, the time domain signal represents the DC output voltage
fiom the essential bus TRUs. The DC voltage npple was measured at 650.8 mV, and
modulated with a low frequency sinusoida1 modulation of 0.035 Hz This low fiequency
oscillation could be attnbuted to tonional shaft oscillations fiom either the aircraft engine
or voltage generator. The voltage ripple is within the maximum dowable limit of 1 .O V
peak-to-peak [ î6] .
The harmonic plot shown in Figure 4.53 represents discreet characteristic
frequencies, which are inherentiy produced by the TRUs. As previously described, the
TRU is a tweive-pulse device constructeci h m two parailel connected six-phase
rectifiers. The output of each rectifier pmduces an output frequency of six times the
fimiamenta1 which is 2400 Hz. The output fiequency from the TRU is twelve times the
fùndamental fiequency, or 4800 Hz. One would also expect to find multiple fiequencies
of 800 Hz. The harmonic characteristics shown in the DC plots are quite unique and
distinct from the AC harmonic plots. In the DC voltage harmonic plot one can easily
identi@ three distinct harmonies. The first peak represents the second harmonic or
800 Hz, the second peak (highest dB level) is the 6" haxmonic (2400 Hz), and the third
peak represents the 12' harmonic (4800 Hz) or output ripple fkquency. The dominant
6" hamionic represents the output fiequency (2400 Hz) fiom both parallel-connected Y-Y
and A-Y six-phase rectifiers. This observation clearly shows that the hannonic
characteristics for a rectifier is not only dependent on the pulse number of the device, but
also its design characteristics. Harmonies generated on the DC side of the rectifier are
even numbered, and predominantly odd numbered on the AC side. The 6" harmonic dB
level was measured at 99. f 4 mV and is within the maximum distortion limit as defined in
MIL-STD-704E. The output DC voltage was measured at 29.6 V, which is within the
operating iimit.
START: O Hz 8W: 31.25 Hz STOP: 12 500 Hz I
27.4 v
STAAR O Sec I
STOP: 32 nSac X: 2378 Hz Y: 99.14 nVrm 'THO: 70.5 X
Figure 4.53 - Case2: Essential DC Bus - TRU DC Voltage & Harmonic Profile
"Aircraft Triai"
Figure 4.54 shows the DC output current wavefonn fiom the essential bus TRU
No. 1 and associated hannonic profile plot At f3st glance, the waveform appears to
represent an AC signal. Analysis of this signal shows that it consists of two components,
a DC component measuring 43.6 A superimposed on a 9.85 A, 400 Hz osciilation.
The harmonic plot confirms this analysis. The fm harmonic, which is identified
with an X at its peak, represents the 400 Hz signal (dominant harmonic) as shown in the
waveform. The next two predominant frequencies represent the 6' and 12' harmonics.
As previously described, these even numbered hmonics identiQ the DC ripple
characteristics of the rectifier. In addition to the DC characteristics, one cm clearly
identify the 7', 1 lh, 13", 17", 19", 23"', and the 25" harmonics. Al1 of these harmonics
are odd numbered, which represents the AC characteristics of the TRUs. This
observation indicates that TRU No. 1 is not providing sufEcient filtering to remove the
AC component fiom the DC. This TRU should be replaced with a serviceable unit.
m A STAR^: O Hz en: 31.2~ HZ STOP: i a soo HZ
X: 406 -26 Hz Y: 9.849 Arms THO: 20.4 %
Figure 4.54 - Case 2: Essential DC Bus - TRU 1 DC Current & Harmonic Profile
"Aircrafl Trial"
Figure 4.55 represents the essential bus TRU No. 2 output DC cunent waveform
and associated harmonic profile plot. The waveform DC ripple characteristic is very
similar to the DC voltage ripple. The DC current ripple was m e m e d at 3.0 A and the
output current at 45.6 A Also shown is the 0.035 Hz oscillation.
The harmonic plot also shows the inherently produced DC TRU characteristic
harmonies. In this plot, the 12' harmonic dB level is larger than the 6U> harmonic, which
is in contrast to the DC voltage harmonic profile, where the 6" harmonic dB level is
larger than the 1 2 ~ harmonic. The dominant 12" harmonic represents the output
fiequency (4800 Hz) fiom the twelve-pulse TRU converter. One other dissirnilarity was
observed, the 23d, 24', and 25' hamionics are show in the current plot but not in the
DC voltage plot. It is interesting to note that the THD value for the TRU No. 2 DC
current was measured at 19.1%, and the THD for the TRU No. 1 DC current at 20.4%,
and the DC THD value at 70.5%. As previously described in section 2.2.1, THD values
should be used as a figure of merit ody and in association with the electncal distribution
system-loading configuration.
START: O Hz BW: 3i.25 Hz STOP: 12 500 Hz
J START: O Sac STOP: 32 mSec X: 4780 HZ Y: 677.3 mArm THII: i 9 . i X
Figure 4.55 - Case 2: Essential DC Bus - TRU 2 DC Current & Harmonic Profile
"Aircraft Trial"
Figure 4.56 is a multiple waveform plot showing three simultaneous waveforms.
These wavefom were recorded on the same tape recorder and synchronized in tirne.
The upper waveform represents the output current from the essential bus TRU No. 1, the
middle waveform is the DC output cumnt fiom TRU No. 2, and the lower waveform is
the essential DC voltage. These wavefoms were recorded when the HF radio was
transmitting.
As shown in the upper waveform, the input range of the recorder clipped a
segment of the positive peaks. As a result, the maximum peak current value was not
recorded. However, knowing that the input range scale for both current sensors were
calibrated to measure up to 300 A, the current value representing the clipped segment cm
be recovered. The recovery cm be accomplished by fhding the ratio (scale factor)
between the middle waveform and the correspondhg upper non-clipped segment of the
signal. Using this technique, the maximum current magnitude was calculated at 33 5.9 A.
Since the TRU is rated at 200 A, the TRU transfomers (Y-Y and A-Y) may be operating
non-linearly during this period when the HF radio is transmitting. This situation would
generate additional harmonies on the essential bus and possibly cause unwanted
frequency interference to avionics equipment.
The average curent value for TRU No. 2 was measured at 150.0 A. As
previously indicated TRU No. 1 is not providing sufEcient filtering and requues
servicing. The DC voltage was measured at 29.6 V and does not appear to have produced
signincant transients during this event.
As shown in Table 3.1 1 for Cases No. 5 and 6, the main bus TRU output currents
were measured at 63.0 and 47.4 A. This observation indicates that the TRUs are not
providing symmetrical output cumnts (24.8%), which could lead to undue stress on the
higher current-carryîng TRU during heavier DC loading. A similar observation was
noticed for the AVTRûN shop mode1 (Table 3.8 Case 3A) where TRUs No. 1 and 2
produced 87.0 A and 11 1.0 A, respectively. This situation represents an unbaianced
condition of 27.6%. The essentid bus TRUs produced a curent unbalance of 6.0%.
. . - - - . . -. - . . ~sseritial Bus TRU No. I Current
- -*- -
Figure 4.56 - Case 4: Essential DC Bus: "TRU DC Voltage & No. 1 and 2 Current"
''Aimafi Trial: HF Radio Transmit Mode"
Chapter 5 Conclusion
5.1 Summary of Work
During the past several decades, there has been considerable interest in the power
quality of electric distribution systems. Voltage and current harmonies, including
sporadic transients, are major electrical system perturbations, which can cause significant
electrical waveform distortion. These distortions can sigaificantly impair the
performance and operation of electrical and electronic equiprnent.
The objectives of this thesis were to investigate the power quality of an aircraft
electrical power distribution system through the use of computer simulation, laboratory
models, and aircraft measurements.
The computer simulation mode1 was developed using ~ ic ro~ran" , a transient
analysis program computer tool. ~ i c r o ~ r a n @ , was used to simulate one engine generator,
three-phase AC distribution conducton, three-phase essential and main bus loads, single-
phase and three-phase transient loads, two transformer rectifier units, and DC loads to
represent the essential and main bus loading conditions.
Six distinct test case scenarios were designed to emulate various loading
conditions. The test case scenarios were simulated and the results compared with the
data measured fkom the AVTRON laboratory mode1 and aircrafi triai. The fint scenario
was implemented to identiQ the three-phase AC bus voltage and Iine current waveform
characteristics imposed by the TRUs during a no load condition. The second scenario
was devked to emulate the aircraft essentiai DC bus Ioading condition. Test cases No. 3
and No. 4 were deviscd to emulate the aircraft's essential three-phase AC bus reactive
load and a three-phase switching load (HF radio), including the essential DC bus load.
The final two test cases were developed to emulate the aircraft's main three-phase AC
bus load, a single-phase switching load (search radar), and the main DC bus load.
Harmonic andysis was performed on both voltage and cunent waveforms derived
fiom al1 six test case scenarios and the results were compared with the simulation model,
laboratory model, and aircrafi triai data. The hamonic results showed that the 11" and
13" harmonics were dominant fiequencies for the simulation, laboratory model, and
aircraft trial. These hamonics represent characteristic harmonics generated from a
twelve-pulse cornmutated converter. The laboratory mode1 and aircraft trial DC voltage
and current spectral density results, showed that the generated characteristic harmonics
were the 6" and 12" harmonic. These harmonics represent the output ripple fiequencies
fkom the two parallel-connected six-phase rectifiers and the output npple fiequency fiorn
the TRUs. DC harmonic analysis was not conducted for the simulation model.
Simulation results showed that the phase voltage, line current, and PF were
comparable with results derived from the laboratory model. However, to achieve these
results, the simulated generator peak output terminal voltage required incremental
adjustments as the AC and DC loads varied. The initial peak generator terminal voltage
was set at 162.6 V for case 1 and incrementally adjusted to 186.6 V for case 4,5, and 6 to
maintain AC bus voltage levels, which were comparable to the laboratory model and
aircraft trial data. Two independent simulation runs were conducted for each test case to
compare THD values as a result of modifjing the TRU transformer excitation current and
core loss vaiues kom the laboratory measured data to the OEM's recommended values.
The resulting data demonstrated that the OEM recommended excitation cunent of 5.0%
and three-phase core loss value of 43.0 W produced a leading PF in the hrst scenario and
generated a slight increase in THD values for both the voltage and current waveforms in
al1 test cases. The simulated voltage THD vaiues for dl test cases were on average
70.8% greater than the laboratory model results and the cunent THD value were 4.1 %
Less. Udortunately, for the aircrafi triai, the voltage data for al1 ihree-phases were lost,
and as a result, the voltage THD values for the aircraft trial were not compiled.
Test cases No. 4 and No. 6 represented transient studies. A three-phase essentiai
load (HF radio), and a single-phase main load (search radar), were switched on and off to
determine the transient response tiom these events. Analysis of both the voltage and
current waveforms generated fiom the simulation and laboratory test r e d t s did not
reveai significant transients. However, during the aircmft ûial when the HF radio was
keyed-on (transmit mode) excessive modulation appeared on the DC output current from
TRU No. 1, exceeding its 200 A rating by 136 A. If the TRU transfomers operate as
non-linear devices during radio transmission, as a result of transfomier core saturation,
then hannonic levels on the AC bus will increase.
This study also examined the aircraft essential AC bus three-phase loading
profile. The loading profile results showed unbalanced load conditions that exceeded the
maximum allowable iimit as defined by MIL-STD-704E specifications for test case No. 2
to 4. As much as 421 VA exceeded this b i t . Unbalanced load conditions will produce
current flow in the neutral conductor and induce a voltage potential between the neutral
and aircraft ground.
The AVTRON laboratory mode[ test results for case No. 5 revealed an anomdy
with the phase B load bank. The AVTRON load bank was used to represent the three-
phase load for this case scenario. The three-phase voltage and cunent waveform analysis
revealed that the complex power loading for phase B was measured at 18 14.0 VA with a
0.99 PF, even though the load bank was adjusted to provide a per phase loading of 2245.0
VA with a PF of 0.73. This observation indicates that the phase B reactive component
was defective in some way (ie. not connected). A unity PF (z 0.99) represents a resistive
load.
Based on observations made during this study, it could be concluded that there are
several issues, which should be addressed. It is recornmended that the work of this study
provide the basis for the following areas of work:
1. Implement an on board aircraft electrical power monitoring system that wouid
continuously monitor the electrical stanis of the power distribution system. The
monitoring system could be used to prevent or minimize system degradation or
as a preventive maintenance tool to identify phase unbalances, load flow
profiles, voltage switching transients, or voltage and cunent total harmonic
distortion during various flight profiles. The electricai data could also be used
to identiQ unpredictable system behaviour or to capture the electrical power
distribution phase voltage and current signatures as a fiequency spectnun to be
used as a baseline for fùtwe trend analysis.
2. Conduct a fleet wide survey to determine the existing three-phase AC load
profile on the essentiai AC distribution bus. Electrical signals recorded during
the aircraft trial showed a three-phase load unbalance of 1229.2 VA, which
exceeds the maximum allowable limit by approximately 429.0 VA as defined
by MIL-STD-704E [22]. Three-phase load balancing may be required.
3. Conduct a fleet wide survey to measure the paired TRU DC output currents for
unbalances. The AVTRON shop model and aircraft trial has shown DC output
current unbalances in excess of 23%. TRU's scheduled for periodic
maintenance or unscheduled replacement should be replaced as baianced pairs.
4. Replace the essential bus TRU No. 1 on aircraft CC-130326E. The TRU No. 1
DC output current harmonic profile as shown in Figure 4.54 indicates the TRU
is not providing sufficient filtering to rernove the AC component fiom the DC.
5. Repais the AVTRON shop phase B load bank reactive component assembly.
Electricai signals recorded during the implementation of the AVTRON model
case 5 and 6 indicates a PF of 0.99 on phase B. During these two scenarios, the
AVTRON load bank was adjusted to provide a three-phase AC load with a PF
of 0.79.
5.2 Recommendation for Further Work
It has been shown that M.icro~ran@ is a very flexible and powerful simulation
tool. Additionai work related to this study should adopt ~ i c r o ~ r a n ~ to improve or
extend this work.
The work of this study could be furthered in the following ways:
To improve the simulation performance of the TRU, the exact value of the
T'RU centre tap balancing transformer and output filter inductor should be
detennined. The simulation results have shown that the DC output voltage
ripple magnitude and the percent of THD for various test cases varied
significantly as a result of changing the value of either the centre tap
balancing transformer or output filter inductor.
Perfom additional excitation and short-circuit testing on a TRU transformer
that does not have the primary windings connected in either a Wye or Delta
and secondary windings connected as a Forked-Wye or Double-Zigzag
configuration to improve winding and core loss performance of the
transformer model.
ModiS, the simulation voltage generator parameter values such as the
armature resistance, armature leakage reactance, zero sequence reactance,
exciter resistnnce, no-load field current, direct and quadrature axis
synchronous reactances, and the subsynchronous and transient reactances to
improve voltage regulation. investigate the feasibility of implementing a
voltage regulator circuit.
Develop a simulation model to emulate the entire CC430 Hercules aircraft
electrical distribution system. This model would include four engine AC
generators, one air turbine motor (ATM) AC generator, associated bus tie
transfer contact switches, AC and DC bus distribution systems, and four
transformer rectifier units. AC generator bus tramfer switching transients
could be analyzed h m this model.
REFERENCES
D.J. Pileggi, N.H. Chandra, A.E. Enamuel, "Prediction of Hamonic Voltages in Distribution Systems", IEEE Transactions on Power Apparatus and Systems,
VOL PAS-100,No. 3, March 1981, pp 1307-1314. R.B. Standler, "Equations for Some Transient Overvoltage Test Wavefoms",
IEEE Transactions on Electromagnetic Compatibility, VOL 30, No. 1, Febmary 1988, pp 69-71.
D.D. Ship, "Harmonic Andysis and Suppression for Elrctrical Systems Supplying Static Power Converters and Other Nonlinear Loads", IEEE Transactions on Industry Applications, VOL IA- 1 5, No. 5, September/October 1979, pp 453-458. "IEEE Guide for Harmonic Control and Reactive Compensation of Static Power
Converters", IEEE Standard 5 19, 198 1.
R.B. Standler, "Protection of Electronic Circuits fiom Overvoltages", John Wiley
and Sons, 1989.
H.C. Cooper, R. Mundsinger, "Power Protection Reduce Electronic Downtime", IEEE Power Quality Proceedings, October 1989, pp 25 1-269.
R.P. Stranord, "Harmonic Pollution on Power Systems - A Change in Philosophy", IEEE Transactions on Industry Applications, VOL IA-16, No. 5,
SeptemberfOctober 1980, pp 6 17-623. R.B. Standler, "Use of a Metal-Oxide Varister with a Series Spark Gap Across the
Mains", IEEE, 1990, CH2903-3/90/0000-0 153, pp 1 53- 1 58. P.J. Leong, LS. Mehdi, "Dynamic Andysis of Elecûical Systems", Boeing Aerospace Company, Seattle, WA 98 124, IEEE, 1978, CH 1336-7/78/0000-0752.
E. W. Schilling, "The Distortion of Current and Voltage Waves on Transmission Lines", PhD Dissertation, Iowa State University, Ames, IA, 1933.
"Power System Hmonics", IEEE Tutorid Course, 84EH0221-2-PWR.
"Study of Distribution System Surge and Harmonic Characteristics", Electric
Power Research Institute, EL- 1 627, November 1 980.
"Power System Harmonics: An Overview, IEEE Working Group on Power Systems Harmonics, IEEE Transactions on Power Apparatus and Systems, VOL PAS-102, NO. 8, August 1983, pp 245592460.
J.S. Subjak, J.S. McQuillOn, "Harmonics - Causes, Effects, Measurements, and Analysis: An Update", IEEE Transactions on Indusûy Applications, VOL 26, No. 6, November/December 1990, pp 1034-1 040.
R.P. Stratford, "Rectifier Hamionics in Power Systems", IEEE Transactions on
Industry Applications, VOL IA-16, No. 2, MarcWApd 1980, pp 27 1-276. LM. Frank, C.R. Luebke, "Transients and Harmonics in an industrial and
Commercial Electrical System", IEEE CH2272-3/86/0000-0974, 1986, pp 974-
981. A.Y. Chikhani, M.M.A. Salama and S. Fouda, "Harmonics Causes and Effects in
Distribution Systems", Royal Military College of Canada, Kingston, 1993.
D. Fair, J. Dhyanchand, E. Parker, H. Bahanassy, "Digital Simulation of Aircd Electrical Generating System by Means of Sceptre Program", IEEE, 0547-
3S78/8 1/0000- 1200. I.D. Segrest, D.L. Sommer, "Computer Modeling of an Aircraft HVDC Electricai
System", IEEE, 0547-357818 1/0000- 1 192. E.L Woods, "Aircrafk Electrical System Computer Simulation", The Boeing
Company, 199 1. A. Fanthorne, G. Kettieborough, "The Simulation of Aircraft Electncal Power
Systems", Copyright by Simulation Councils, Inc., August 1980. A i r c d Electnc Power C haractenstics, Military-Standard-74OE, 1 May 1 99 1 . "Canadian Forces Technical Orders C- 12- 1 30-OF0 MF-204 VOL 1, Electrical
System, 198 1. "IEEE Standard Dictionary of Electncal and Electronic Terms", IEEE Standard
100,1988. Central Station Engineers, "Electricai Transmission and Distribution".
Westinghouse Electric Corporation, 1 964. "Technical Manual Overhaul Instructions with Parts Breakdown", Power Supply Part No. 28VS200C-1, Type No. ECU-23/A, TO 8C14-6-6-13, Wagner Electric Corporation, Tung-Sol Division, 3 0 April 1 990. B.R. Gungor, "Power Systems", Harcourt Brace Jovanovich, 1988. H.W. Domel, "Electrical Magnetic Transient Program Theory Book", Microtran Power System Analysis Corporation, May 1992. Yao-nan Yu, Electnc Power System Dynamics, Academic Press, 1983.
MIL-W-î2759/11 F, Military S peci fication S heet, Wire, Electric, Fluoropolymer- W a t e d , Extruded TFE, Siver-Coated Copper Conductor, 600 Volt,
10 September, 1976. "MicroTran Reference Manual", Microtran Power System Analysis Corporation, September 1992.
[32] Aian L. Black, Sundstrand Transformer P/N 93 9D69S- 1, Facsimile, Sundstrand Aerospace Corporation, 4 Febuary 1993.
[33] B.M. Weedy, "Electric Power Systems," John Wiley & Sons Ltd, 1979.
[34] M. Baier, "Reducing Costs, Improving Power Quality with Harmonic Filters", Electricity Today, VOL 3, No. 4, April 199 1.
[35] H.M. Beides, G.T. Heydt, "Dynamic State Estimation of Power System Harmonies Ushg K h a n Filter Methodology", IEEE Transactions on Power Delivery, VOL 6, No. 4, October 1991.
Appendix A Essential and Main Branch Power Consumptioa Tables "Cruise and Taxi Operathg Conditions"
Table A.1- Tabulation of AC Power Consumption
1 Operating Conditions 1 Taxi 1 Cruise
1 1 1 1 a 1
Essential AC Bus 1 B 1 1994.28 1 0.71 1 1421.03 1199428 1 0.71 1 1421.03
Source of Power r
Main AC Bus
A
Table A.2 - Tabulation of DC Power Consumption
AC Inst & Engine Fuel Control Bus
1 Operatine: Conditions 1
S (VA) 9218.48
I I Cruise I
A
I 1 1 1 L
Main DC Bus 1 163.15 1 4567.80 1 199.09 1 5574.12 1
PF 0.76
524.58
A v g o 7053.13
0.92
S (VA) 9465.94
I
480.34
PF 0.76
Avg 7265.63
524.58 0.92 480.34
Table A.3 - Essential AC Bus Power Consumption during Tari Condition
No. of
Unita
Volt-Amp Per Unit - Per Phase Average
Operating Watts
Power Factor Equipment
Flight Instrument Transformer Loss -
Load - I
Hydraulic Aux Pump Ide -
1 Fuel Boost Pump No.2 ==SOS HF No. 1
Transmit - I AN/ARN-504 Tacan
Transmit - AN/APN-150 LOW Range Altimeter HSI No. 1 & No.2 C-12 Compass Flight Director Propeller S ync hrop haser Instrument Lighting Transformer Loss -
Lighting - Hydraulic Suction Pumps ARN-509 Omega APN-50 1 A Doppler AN/ARN-67 Glideslope No. 1 & No. 2 URT 26 FDRfCPI 63.75
Total Average Watts
7053.13 142 1 .O3 1357.28
Total Volt - Amp
Power Factor Source of Power
r
A Phase B Phase
r
C Phase
92 18.48 1 994.2 8 1896.25
0.76 0.71 0.71
~ a b k 4.4 - Essentid AC Bus Power Consumption during Cruiae Condition
Volt- Amp Per Unit - Per Phase hl Average
Power Operating Factor Phase Phase Phase
No* of
Units
transfo&^ Loss -
Fuel Bo& h m p No.2 IG&a
1 TransfodP Loss - 1
Power To ta1 Total Avemge
Volt - Amp Factor Watts I $tjsfce of Power
Table A S - Main AC Bus Power Consumption during Taxi Condition
Equipment
1
Fuel Boost Pump No. 3 LH AUX Boost Pump RH Aux Boost P w p LH Ext Pump (AA) RH Ext Pump (Aft) ANIAPN-133 High Range Radar Altimeter ANIAPN-59E Search Radar
Source of Power
Volt-Am p N o 1 Per Unit - Per Phase Power
I ~ o t a ~ 1 ~ o w e r Volt - Amp 1 Factor
€
A Phase 1 3630.44 0.85 B Phase 1 2232.48 0.73 C Phase 2232.48 0.73
Average Operating
Watts
1 248.00
3 1.50 To ta1
Average Watts
Table A.6 - Main AC BUS Power Consumption during Cruise Condition
Equipment
Volt- Am p Per Unit - f e r Phase of Power
uhits Factor
Fuel Boost Purnp No. 3 LH Aux Boost Pump RH Aux Boost P u m ~
1
1 310.70 310.70 310.70 0.54 1 483.30 483.30 483.30 0.76 1 483.30 483.30 483.30 0.76
1
Dump Pumps No's. 1,2,3, & 4
Source of Power
4 483.30 483.30 483.30 0.76
LH Ext Pump (AA) RH Ext Pump (Att)
Total Volt-Amp
1 483.30 483.30 483.30 0.76 1 483.30 483.30 483.30 0.76
Power Factor
AN/APN- 133 High Range Radar Alt AN/APN-S9E Search Radar
1 162.00 - - 0.98
1 1300.00 - - 0.96
A Phase
Average Operating
Watts
B Phase "
C Phase
3 1 S O Total
Average Watts
4544.50 1
3 1 06.24 1
3 1 06.24
5549.98 0.82 I
4 1 64.84 4 164.84
0.75 0.75
Table A.7 - AC Instrumenb and Eagine Fuel Control Bus Power Consumption
Equipmeot
Liquid Oxygen Indicator Engine Temp Control Amplifier Engine Torquemeter Turbine Inlet Temp Indicator PowerFai1u.e Relay Type D- 1 Fuel Quantity Indicator Fuel Quantity Totalizer Fuel Flow Transmitter Fuel Flow Indicator Instrument Transformer No. 1 (Loss) Instrument Transformer No,2 (Loss)
No. Volt-Amp Power of Per Unit Factor Units
Üymic Pressure Indicator Boost & Emergency Brake Oil Pressure Indicator (No. 1 &2) Oil Pressure Indicator (No. 3&4) Fuel Pressure Indicator
Source of Power
' Hydradic Pressure Indicator
2
2 2 1
I L
1 A Phase 1 524.58 1 0.92
0.18 Rudder Boost Utility Normal Brake & Ram~
Total Volt-Amp
Average Operating
Watts 4.00
160.00
5 .90
5 .90 5 .90 5 .90
Power Factor
Total
0.18
0.18 O, 18 O. 18
5
Average Watts 480.34
5 -90
Table A.8 - Essential DC Bus Power Consumption during Taxi Condition
1 I 1 a - 1 Rudder High Boost Diverter 1
2 1 2.00 1 4.00 1 1 12.00 1 Equipment
- Auto pilot Run -
S M -
No. of
Units
Amps Per Unit
Average Opernting
G m ~ s
19.00 10.70
I
Aileron Tab Control Relays Oil Coder Flaps Position Indicator Landing Gear Position uidicator Anti-Ice Air Temp Indicator Oil Temp Indicator Fuel Flow Power Supply Oil Quantity Indicator Flight Duector System Gyros
Average Operathg
Watts
0.50 0.27 0.17
2 4 3 6 4
Pitot Tube Heater Leading Edge Anti-king Valve Prop De-Ice Timer Spinner Anti-Ice Relays
Cargo Cornpartment Fan Relay 1 0.46 0.46 12.88 Blower Motor 2 0.40 0.80 22.40
1
Actuator T e m ~ Control Valve 1 1.20 1.20 33.60
6.00
1 4 2
Prop De-king Relays Floor Heat Control Valve Floor Heat Shut Off Valve
168.00 I
1 6 1 4
0.50 1 .O8 0.5 1
1 .O0 0.60 0.63
Encoding Altimeter Copilot Altimeter Emergency B d e Selector Valve Landina; Gear Selector Valve
8 1 1
A
Cargo Compartment Flow Control Shut Off
14.00 3 0.24 14.28 16.80 0.10
0.23 0.090 0.60 0.70
1 1 1 1
4.00 1.25 1 .O0 0.40
ice Detectors Standby - Operate -
Idet Vane Anti-king Solenoid Scoop Anti-king Valve
0.60
1 .O0 2.40 1.30
0.50 1 .O0 1 .O0
1
0.04 28.00 67.20 36.40
0.23 0.09 0.60 0.70 4.00 7.50 1 .O0 1.60
* 4 4
0.16 1 4.48
6.44 2.52
16.80 19.60
1 12.00 2 I0,OO 28 .O0 44JO
1 .O0 1 .O0 1 .O0
3.25
28.00 28 .O0 28 .O0
1.00 10.00
Engine Air Anti-Ice Relay Prop Feather Over Ride Switch
1 .O0
1 4
28 .O0
9.80 34.16
2.00 t 8.00
0.35 1.22
4 56.00
504.00
0.35 1.22
224.00 140.00
2.00 1 .25
8.00 5.00
Table A.8 (cont'd) - Essential DC Bus Power Consumption during Taxi Condition
Equipment
Proo Feather Relay 1 4 1 0.20 1 0.20 1 5.60 1
No. of
Units
Amps Per Unit
Feather Pump Motor Relay Feather Solenoid Synchrophaser Assembly Manuai Phase & Master Trim Control Oil Cooler Flap Achiator Oil Temp Control Thermostat Low Speed Ground Ide Switch Low beed Selector Solenoid
~ver<e Operating
Amps
4 4 1 1
Tai1 Lights (Navigation) W ing Tip Lights (Navigation) Flasher
Average Operating
Watts
4 4 4 4
Control Surface Hydraulic Shut Off Valves - Waming Lights -
Bleed Resisîors Reverse Current Relays Engine Temperature Control Relay Fuel Correction Lights Temperature Dahun Control Valve Speed Sensitive Relay
I 1 1 I
ARC 505 HF No.1 1 1 1 3.60 1 3 -60 1 100.80 1
0.46 1 .O0 0.45 0.15
2 2 1
w
Engine Fire Waming Cont Essentid DC Bus Relay Overheat Thermostat
5.00 0.35 0.20 2.00
6 6 2 3 4 4 4 4
0.46 1 .O0 0.45 0.15
0.80 1.15 0.20
Landhg Light - Light Assembly Glareshield Lights hti-Collision Lights Fuselage Lights Bright - Emergency Exit Light Control Hydraulic Boost & Utility Pump Relay
12.88 28 .O0
3
12.60 4.20
20.00 1.40 0.80 8 .O0
3 .O0 0.34 3 -73 2.70 0.20 0.46
2 5 2 2 2 2
1 .O0 O. 17 5 .O0 0.50 0.20 0.17 1.00
1
5 1 0.20
560.00 3 9.20 22.40
224.00 1.60 2.30 0.20
1
1 ,O0 1 28 .O0 I
16
44.80 64.40 5.60
6.00 1.70 7.46 5.40 0.40 0.92
Awiliary Hydraulic Pump Relay
3 .O0 0.5 1
10.00 1.50 0.80 0.68
i 4.00
0.10 1.60
0.10 0.10
168.00 47.60
208.88 151.20 1 1.20 25.76
0 -45 1 1 0.45
84.00 14.28
280.00 42.00 22.40 19.04
112.00 0.20 1 0.80
2.80 44.80
12.60
22.40
Table A.$ (cont'd) - Essentiel DC Bus Power Consumption during Taxi Condition
Average Operating
Watts 56.00 15.40 28.00
Trammitter - KY5024 Selcai Decoder ANIARN-150 Low Range Alt APN-50 1 A Doppler AYN-50 1 Cornputer ARC 164 UHF Radio Receiver - APX-77 IFF
Equipment
URT 26 FDRICPI ARN-509 Omega ARC4 1 1 VHF Receiver -
Amps Per Unit 2.00
No. of
Units 1 1 2 2 2 1 1 1 1 1
Average Operating
Amps 2.00
Total Average
7.00 4.25 3.40 0.36 1.89 1.21 5-00
To ta1 Average
0.55 1 .O0
I Amps I Watts
0.55 1 .O0 7.00 0.25 3 -40 0.36 1.89 1.21 5 .O0
196.00 7.00 95.20 10.08 53 -00 34.00 140.00
Table A.9 - Essential DC Bus Power Consumption during Cmise Condition
Equipment
I
Autopilot Run - Start -
1 Oil Temp Indic 1 I I 1
1 4 1 0.04 1 0.16 1 4.48 1
No. of
Units
l 1
Autopilot Elevator Trim Relays Oil Cooler Flaps Position Indicator Landing Gear Position Indicator Anti-Ice Air Temp Indicator
Amps Per Unit
Average Operating
Amps
1 .O0 0.50
Elevator Tab Control Relays Aileron Tab Control Relays
Average Operathg
Watts 19.00 10.70
28.00 14.00
4 4 3 6
Fuel Flow Power Supply Oil Quantity Indicator Flight Director System Gyros Encoding Altimeter Copilot Altimeter Emergency Brake Selector Valve
9 2
- 19.00
0.50 OS0 0.1 1 0.27 O. 17 0.10
1 4 2 1 1 1 - -
Pitot Tube Heater Leading Edge Anti-king Valve Prop De-Ice Timer Spinner Anti-Ice Relays Prop De-king Relays
Floor Heat Shut Off Valve Cargo Cornpartment Fan Relay Blower Motor
' Acniator T e m ~ Control Valve
532.00
4.00 1.25 1 .O0 O .40 0.50
1
1 6 1 4 8
Cargo Compartment Flow Control Shut Off
0.22 1 .O8 0.5 1 0.60
1 .O0 0.60 0.63 0.23 0.09 0.60
1 1 2 1
Ice Detectors Standby - Operate -
Idet Vane Anti-king Solenoid Scoop Anti-Icing Solenoid Engine Air Mti-Ice Relay Prop Feather Over Ride Switch
6.16 I
30.24 14.28 16.80
4.00 7.50 1 .O0 1.60 1 .O0
Floor Heat Control Valve
1
1 .O0 2.40 1.30 O .23 0.09 0.60
1 12.00 2 10.00 28 .O0 44.80 28.00
t .O0 1 1 1.00 1 .O0 0.46 0.40 1.20
4 4 I 4
28.00 07.20 36.40 6.44 2.52 16.80
28.00 1 .O0 O -46 0-80 1.20
1
28.00
L
1 .O0 10.00 2.00 1.25 0.35 1 .22
28.00 12.88 22-40 33.60
3.25 1 .O0
2.00 18.00 8.00 5.00 0.3 5 I -22
56.00 504.00 224.00 140.00 9.80 34.16
Table A.9 (cont'd) - Essential DC Bus Power Consumption during Cniise Condition
Average Average Equipment
Prop Feather Relay Feather Pump Motor Relay Feather Solenoid
. 1 1 1 1
Low S ~ e e d Ground Idle Switch 1 4 1 0.20 1 0.80 1 22.40
No. of
Units 4 4 4
Amps Per Unit 0.20 0 -46 1 .O0
L
O .45 O. 15 5 .O0 0.35
S ynchrophaser Assembl y Manual Phase & Master Trirn Control Oil Cooler Flap Actuator Oil T e m ~ Controi Thermostat
*
Low Speed Selector Solenoid Tai1 Lights (Navigation) Wing Tip Lights (Navigation) Flas her
- - - - 1 * 1 r
Overheat Thermostat 1 16 1 0.10 1 1 -60 1 44-80
t 1 4 4
1 a I
ARC 505 HF No. 1 1 1 1 3.60 1 3.60 1 100.80
0.45 0.15
20.00
4 2 2 1
Glareshield Lights Anti-Collision Lights Fuselage Lights Bright - Emergency Exit Light Control Hydraulic Boost & Utility Pump Relay Auxiliary Hydraulic Pump Relay ControI Surface Hydrauiic
Shut Off Valves - Warning Lights -
t 2.60 4.20
560.00
0.34 3.73 2.70 O -20 0.46 0+45
1 .O0 O. 17
1
5 2 2 2 2 1
6 6
1.40 1 39.20
2.00 0.80 1.15 0.20
1 -70 7.46 5.40 O .40 0.92 0.45
3 .O0 0.5 1
Bleed Resistors Reverse Current Relays Aux Tank Dump Interlock Relay Engine Temperature Control Relay Fuel Correction Lights Temperature Datum Control Valve Extemal Tank Dump Interlock Relay Dump Pump On Light Engine Fire W d g Cont Essential DC Bus Reiav
8.00 1.60 2.30 0.20
47.60 208.88 151.20 1 1 -20 25.76 12.60
84.00 14.28
10.00 1 .50 0.70 0.80 0.68 4.00 0.70 0.17 1 .O0
224.00 44.80 64.40
5.60
280.00 42-00 19.60 22.40 19.04
1 12-00 19.60 4+76
28 -00
2 3 2 4 4 4 2 1 5 1
5.00 0.50 0.35 0.20 0.17 1 .O0 0.35 0.17 0.20 0.10 O. 10 2.80
Table A.9 (cont'd) - Essential DC Bus Power Consumption d u h g Cruise Condition
--
Equipment
TACAN AN/ARN-504
1 Average 1 Average
No. of
Units 1
Y
DF-88 I 1
I 1 I
AN/ARN- 14 VHF Nav No. 1 & No.2 1 2 ARA 19 1 ANIARN-6 ADF 2 uRT 26 FDR/CPI 1 I ARN-509 Ornega 1
1 .O0 1 .O0 1 .O0 7.00 4.25 3.40 0.36 1.89 1.21 5-00
BR-1 5 ARC-5 1 1 VElF Receiver -
Trammitter - KY5024 Selcal Decoder AN/ARN-150 Low Range Alt APN-50 1 A Doppler AYN-50 1 Cornputer ARC 164 UHF Radio Receiver - APX-77 IFF
Amps Per Unit 2.00
1 2 2 2 1 1 1 1 1
To ta1
4.40 4.50 2.00 0.55
1 .O0 1 .O0 1 .O0 7.00 4.25 3.40 0.36 1.89 1.21 5.00
Total
Average Operating
Amps 2.00
28.00 28.00 28.00
196.00 1 19.00 95.20 10.08 53 .O0 34.00
140.00
~ v e k g e Operating
Watts 56.00
8.80 9.00 2.00 0.55
246.40 252.00
56.00 15.40
Table A.10 - Main DC Bus Power Consumption during Taxi Condition
Equipment No. of
Units
Amps Per Unit
1
I 1 I
0.80 0.27 0.27 0.27 0.27
Wing Flaps Selector Valve Wing Flap hd & Xmtr
Free Air Temp Ind 1 2 1 0.08 1 0.16
I 1 1 I
Anti-Skid System 1 1 1 6.60 1 6.60 1 184.80
Average Operathg
A m ~ s 1 1
4.48 Recording "Indicator" Accelerometer "Sensor"
Average Opersting
Watts - 0.80 0.27 0.27 0.27 0.27
0.70 0.30
2 I
Control Box & Anning Relay Control Solenoid
- f I 1 1
Formation Liabts 1 9 1 0.17 1 1-53 1 42.84
22.40 7.56 7.56 7.56 7.56
Trim Tab Pos Ind & Xmtr "Rudder" T r b Tab Pos Iad & Xmtr "Elevator" Trim Tab Pos Ind & Xmtr "Aileron"
4.50 0.30
2 2
Bleed Resistors
I 1 1
1.70
- Window Heater Control Box Window Heater Control Relay Radome Anti-Ice Shut Off Valve Cargo Area Floor Lights Oxygen Regulator Lights Dome Lights (Red) Mech & Nav Utility Lights Overhead Panel Lights
Pilot Circuit Breaker Panel Lights Pedestai & Pilot Side Panel Li&
Reverse Current Relays
47.60
9.00 0.60
0.09 0.46 0.20 0.80 0.17 1.50 O. 17 0.04 0.34 0.04 0.04
I
2 4 1
13 10 30 2
158 6 78 91
Taxi L i d t s
252.00 16.80
~aviaakr inst Panel Lights
0.18 0.92 0.20
10.40 1.70
45.00 0.34 6.32 2.04 3.12 3.64
Copilot Side& Circuit Breaker Panel Liahts
5 .O4 25.76 5.60
29 1.20 47.60
1260,OO 9.52
176.96 57.12 87.36
101.92
Light Dimming Control Relays
Table A.10 (cont'd) - Main DC Bus Power Consumption during Taxi Condition
- 1 1
To ta1 Total
-
Equipment
Signal Light Main DC Bus Off Relay ARC 505 HF No.2 MIAPN-59E Search Radar AN/ASO-14 Radar Press
Average Average
163.15 4567.80
No. of
Units 1 1 1 I 1
Amps Average Average Per Operating Operating Unit Amps Watts 5.30 5.30 148.00 0.10 0.10 2.80 3.60 3.60 100.80 6.50 6.50 182.00 3 .70 3.70 1 03.60
Table h l 1 - Main DC Bus Power Consumption during Cruise Condition
Equipmeat
Wing Flap Ind & Xmtr Trim Tab Fos Ind & Xmtr "Rudder" Trim Tab Pos Ind & Xmtr "Elevator" Trirn Tab Pos Ind & Xmtr "Aileron" Free Air T e m ~ Ind
NO. of
Units 1 1
. Recording " Indicator" Accelerometer Sensor"
1 1 2
L
Bmke Selector Valve Conîrol Box & Arming Relay Control Solenoid Window Heater Control Box Window Heater Control Relav
Amps Per Unit 0.27 0.27
2 1
I
Cargo Cornpartment Aux Shut Off Valve
0.27 0.27 0.08
Flight Deck A u Shut Off Valve Radome Anti-Ice Shut Off Valve
Average Operathg
Amps 0.27 0.27
0.70 0.30
I
0.60 1 16.80 9.00 252.00 0.60 1 16.80 0.18 5.04 0.92 1 25.76
1 2 2 2 4
1
Cargo Area Floor Lights Oxygen Reguiator Lights Dorne Lights (Red) Mech & Nav Utility Liahts
Average Operating
Watts 7.56 7.56
I --
0.27 7.56
0.60 4.50 0.30 0.09 0.46
1 1
-
Sextant Light Overhead Panel Lights
Pilot Cucuit Breaker Panel Lights Pedestal& Pilot Side Panel Lights Formation Lights
0.27 0.16
1 .70
1 .O0
-
13 10 30 2
7.56 4.48
47.60
4.50 0.20
1 158 6 78 91 9
1 .O0 I
4.50 1 126.00 0.20 5.60
0.80 0.17 1.50 0.17
28.00
0.04 0.04 0.34 0.04 0.04 0.17
Leading Edge Lights Navigator lnst Panel Lights
10.40 1.70
45 .O0 0.34
1.95 0.04
2 70
29 1 -20 47.60
1260-00 9.52
0 .O4 6-32 2.04 3.12 3 -64 1.53
1.12 176.96 57-12 87.36 10 1.92 42.84
3.90 2.80
Copilot Side & Circuit Breaker Panel Lights Flight Station Lights (Clear)
109.20 78.40
3.12
6.40
87.36
179.20
78
8 1 1.20 19.60
Light DUnming Control Relays J u m Platform Li&
0.04
6.40 2 2
0.20 0.35
0.40 0.70
Table A.11 (coat9d) - Main DC Bus Power Consumption during Cruise Condition
No. Amps Average Equipment of Per Operating
Units Unit Amps Thunderstom Lights 1 2 1 0.70 1.40
I -
Passenger Warning Signs 1 2 1 0.40 0.80 Aft Anchor Line Arxn Control 1 2 1 5.00 10.00 Windshield Wipen 2 1 6.00 12.00 Ramp Door Uplock Inspection Light 1 0.34 0.34 Ramp Position Lights 2 0.17 0.34 Ramp Manifold Control Valve 1 4.80 4.80 v ami D o m Unlock Relay 1 0.20 0.20 Air Deflector Open Lights 2 0.17 0.34 Air Deflector Actuator 2 6.00 1 12.00 Signal Light 1 5.30 5.30 Air Drop Release Solenoid 1 6.00 6.00 Static Line Retriever Winch 2 80.00 80.00 Retriever Control Relay 2 0.20 0.20 Retriever Power Relay 2 0.70 0.70
Reverse Current Relays 3 0.50 ( 1 -50 Main Dc Bus Off Relay 1 0.10 0.10 ARC 505 HF N0.2 1 3.60 3.60
1 ARNI27 VORmS Marker Beacon 1 1 1 2.00 1 2.00 Flight Director Relay 2 1 .50 2.3 O ANIARA-25 UHFIDF 1 1 .O0 1 .O0 ANIAPN-59E Searcb Radar 1 6.50 6.50
1 AN/ASQ-14 Radar Press I 1 1
1 1 1 3.70 1 3 JO I - 1 1
Total 1 Average
Average Operating
39.20 22.40
Total Average Watts 5574.12
Appendix B
Derivation of TRU Transformer Mode1 Parameters
The TRU mode1 28VS200C-1 is a convection-cooled, static AC to DC converter
designed for airbome and ground applications. It operates from a 200 Volt, 400 Hertz,
three-phase AC source, and provides 200 Amperes of continuous current at a nominal
28 Volts DC. Each TRU is rated at 6.3 kVA with a power factor of 0.95 [30]. The TRU
phase transformation occurs through the use of dual primary (Delta-Wye) three-phase to
six-phase secondary forked transformer configuration. Each transfomer phase is rated at
1 .O5 kVA.
B. 1 Open-Circuit Test
The open-circuit transformer test configuration as shown in Figures B.1 and B.2
were used to determine the MicroTrd excitation test data. The excitation test data
Uicludes the excitation current and single-phase power Ioss in the Y-Y and A-Y
transformer configurations.
Figure B.1- Y-Y Open-Circuit Test "Two Wattmeter Methodw
Figure B.2 - A-Y Open-Circuit Test 6"Two Wattmeter Method"
The-phase power can be measund by ushg either three or two wattmeters. A
single wattmeter could be used to measure three-phase power providing the system is
assumed to be balanced. The two-wattmeter method was used to derive the excitation
test data.
Each wattmeter, W1 and W2, measures the product of the line voltage and the
cunent it is connected to, times the cosine of the angle between the voltage and current.
Hence,
W, = Ed I , cosOtmbl = EL LL COS(~O + O)
W2 = E,I, COSO~,~, = El. LL cos(30-8)
and the sum of W1 and W2 represents the total three-phase power:
4 +W2 = E L L L [ ~ ~ ~ ( 3 0 + 8 ) + ~ ~ ~ ( 3 0 - 8 ) ] W
4 + 6 E L L L , ( 2 ~ ~ ~ 3 0 ~ ~ ~ û ) = fi^,^, COS@ W
P=W, +w, =JSE,I ,COSB w
and the difference
is ilfi times the reactive power. Therefore, the product of f i and the difference
between W2 and W1 represents the total the-phase reactive power.
Hence,
and the phase angle between EL and I L can be caiculated fiom the following:
and the cornplex power h m
Table B.l represents the Y-Y and A-Y transformer test data measured from the
open-circuit configuration as shown in Figures B.1 and B.2, respectively. The data
indicates that the Y-Y and A-Y transformer three-phase design is not perfectly
symmetrical due to the slight difference in mutuai impedance between the center and
outer transformer legs.
The transformer rated current Id was detecmined to be 8.64 A and defhed
from the following expression:
(B- 10)
where EL is defined as the rated line voltage, and the excitation current as:
where (Ewl + E,+,,)/2 represents the average phase voltage EL and W, + W2 the measured
power.
The percent excitation curent is defined by:
Table B.1 - Y-Y & A-Y Open-Circuit Test Data
B.1.1 Transformer Iron Losses
The sum of W, and W, as show in Table B. 1 represents the total transformer uon
losses and defined as P (W) in Table 8.2.
B.1.2 Excitation Test Data
Table B .2 represents the excitation test data derived fiom equations (B-5), and
(B-7) to (B- 12), and table B. 1 data.
Table B.2 Excitation Test Data
B.1.3 Transformer DC Resistance
The primary and secondas, winding resistance &, values for both transformer
P-Tl and P-T2 were mensured using a four-wire milliohm meter. The delta prirnary P-T2
input terminal, line to line resistance, was measured at 0.150 R. Hence, the individual
delta p n m ~ winding resistance value may be determined f?om the following expression:
(B- 13)
where R, = P-T2 input line to line resistance.
The Y primary POT1 input temiinal, line to line resistance, was meanued at
0.58 R. The individual Y primary winding resistance value is one-haif the measured
value. Hence,
where R, = P-Tl input line to line resistance.
The secondary winding line to neutral resistance for both Tl and T2 was
measured at 0.002 R. Therefore, each secondary winding resistance value R, is defined
as:
(B- 1 5 )
where R, = line to neutral secondary resistance.
B.1.4 Transformer Secondary Voltage
The six-phase line to neutral secondary voltage as shown in Figures B. 1 and B.2
was measured at 21.55 V. Therefore. each secondary winding delivers:
(B- 16)
where V, = line to neutral secondary voltage.
B.2 Short-Circuit Test
The short-circuit transformer test configuration as show in Figures B.3 and 8.4
were used to measure the data required to calculate the short-circuit hpedance and load
losses. Note that aiI output secondary windings are shorted together. The amp-rneter was
used to measure and monitor curent flow during the short-ckuit test. To satis& the
MicroTd detailed eaasformer mode1 input data requirement, exactiy N x (N - 1)/2
short-circuit tests are required where N is the total number of per-phase windings.
Therefore, a total of six shortcircuit tests were required for POT1 and P-T2.
P-T I
Figure B.3 - Y-Y Short-Circuit Test UTwo Wattmeter Method"
Fipre B.4 - A-Y Short-Circuit Test "Two Wattmeter Method"
Table B .3 represents the laboratory short-circuit test data as a function of primary
winding line current.
Table B3 Y-Y & A-Y Short-Circuit Test Data
The diagrammatic methodology as shown in Figure B.5 was used to determine the
transformer load losses and short-circuit impedance. Figure B.5 (a) represents the
transformer as an equivaient resistive load R,, B.5 (b) differentiates between the
primary P, and secondary S, windings, and B.5 (c) between the primary and individual
secondary phase S,, windings. The use of this methodology assumes that 50% of the
power loss occurs in the primary windings and 50% power dissipation in the secondary
windings. It is also assumed that the mutual inductance between the primary and
secondary phase windings are symmetncal.
Figure B.5 - Transformer Equivalent Circuit for Short-Circuit Test
B.2.1 Short-Circuit Impedance
The short-circuit impedance in percent for the short-circuit test between windings
"i" and "k", based on Srat, and on the rated voltages of both windings is defined as:
where i = 1, represents the primary phase windings, and k = 2,3,4, the secondary
windings.
and
The transformer short-circuit impedance Z, is defined as:
(B- 19)
for the transformer configuration Y - Y and A - Y , respectively, where the short-circuit
line voltage EL is defined as ((E,, + ~ , , ) / 2 ) / f i for Figure B.3 and the short-circuit
phase voltage as (Ewl + E,,)/2 for Figure B.4. The corresponding Iine current IL is
defmed by (8-1 1) and the phase curent I , from (B- 1 1) / f i .
The base impedance 2, is defmed as:
for P-Tl in Figure 8.3, where E,, is equal to 1 15 V and 1, at 8.805 A.
The base impedance for P-T2 in Figure B.4 is defhed as:
R
where & M d the rated phase voltage is equal to 200 V and I, , the rated phase
c-nt at r J J 5 .
B.2.2 Short-Circuit Resistance
The short-circuit resistance R, as shown in Figure B.5 is defined as:
where Pr? is the measured short-circuit power. and Ir. the short-circuit curent as
deterrnined From (B-8) and (B- 1 1 ).
The short-circuit resistance R,t.J,4 for the secondary phase windings 2,3, and 4 as
shown in Figure B.5 (c) is defmed as:
and, the short-circuit impedance Zil % for i = 2 , k = 3,4 and i = 3 , & = 4 is defined as:
B.2.3 Transformer Load Losses
4, represents the transformer phase load losses in the short-circuit test. The
iransformer winding losses for 4, where i = 1 , the primary phase windings, and
k = 2,3,4 , the secondary phase windings, is defined as:
andfor i = 2 , k = 3 , 4 and i = 3 , k = 4
The short-circuit impedance and load loss data as shown in Table B.4 was derived
from Table B.3 data (shaded cells) and equations (B-17) to (8-26).
Table B.4 Y-Y & A-Y Short-Circuit Test Data Between Windings I & K
B.3 TRU Transformer Configuration
i, k
1.2
The Y-Y and A-Y TRU hsuisformers are designed as a three-leg iron core
configuration and shown diagrammatically in Figure 8.6. The node names and secondary
winding phase connections were used as input data to replicate the transfomers in
~icro~ranb.
Y - Y
Figure 8.6 - TRU Transformer Connectioa Coniiguration
A - Y Zj, (%)
1.51 4, (%)
1.33 P,& (KW) 0.00745
P,j
0.00786
Appendix C
Recording, Reduction, and Support Equipment for AVTRON Laboratory Model and Aircraft Testing
C.l Recording Equipment
C.1.1 Draneb Power Quality Waveform Analyzer
Model: 658-400 Range: 0-600 V,,, 61 20 V peak
0-1000 Arms, 6000 A peak Frequency : 45-65 HZ, 3 10-445 HZ Accuracy : Voltage: f 1 % reading
C urrent: It 2% current
C.1.Z AEMC AC Current Probe
Mode1 : SD60 1 Range: 0.05-1000 A Frequency : 30-50k Hz Accuracy : f 1 % reading
C.1.3 Fluke DC Current Probe
Model: 80i-1010 Range: 1 - 1 OOOA Frequency : dc-440 HZ Accuracy : f 2% reading
C.1.4 Analog Device Isolation Amplifier
Model : AD2 t OAN Range: Input: il0 V
output: up to 100 v Frequency : 0-20k Hz Accuracy : i 2% maximum
C.1.5 Teac VHS Tape Recorder
Model: XR-510 Channel: 14+1 Speed: 76.2 c d s Range: dc-20k HZ Mode: FM Distortion: 1% or less
C.2 Data Reduction Equipment
C.2.1 Philips Digital Oscilloscope
Model: PM 3375 Range: 4OOV@ 125Hzto 10V@ 1 O O M H z Accurac y : 1 3 % reading for time and voltage Bandwidth: 100 MHz Sarnpling Rate: 250 M sampleds
C.2.2 Hewlett-Packard Dynamic Analyzer
Mode1 : 3561 A Range: 3m-22.4 V Frequency : 0- 1 00k Hz Accuracy : f 0.0003% reading of fiequency
C.2.3 Astro-Med Chart Recorder
Mode1 : MT-9500 Channel: 8 Range: + S V Freguenc y : dc3 k Hz, flat
dcdk Hz, d o m < 3dB, Ml scaie Accumcy : f 1.3% reading
C.2.4 Hewlett-Packard Graphie Plotter
Mode1 : 755OA
C.3 Support Equipment
C.3.1 General ElectricLeland Generator
Model: 2CM353ClIWP Rating: 3-Phase 40 KVA Output Voltage: 1 19200 VAC Frequency : 380/420 Hz Rotationai Speed: 5700/6300 RPM Power Factor: 0.75
C.3.2 Transformer Rectifier Units
Model: 28VS2OOC- 1 Input AC: 3-Phase 190 to 210 V Output DC: 30.5-24.2 V @ 5 to 210 A Power Factor: 0.95
C.3.3 Bleeder Resistors
Serial No. 8370 Rating : 1200 W Resistance: 0-25 ZZ
Serial No. 0448 Rating : 500 W Resistance : O- 12.5 S2
C3.4 Fuse
Model: Gould CRN 200 Type: D T h e Delay Rating : 200 A
C.3.5 Circuit Breakers
Model: MS25244-25 Mode1 : MS25244-20
C3.6 Resistive Load Bank
Model: D95917A-3 for "DC Loads E & F" Rating : 10 KW No. of Elements: 9 @ 1.0 R
C.3.6 Resistive Load Bank (cont'd)
Serial No. 0264 for "AC Load A, B & C " Rating : 5 KW
C.3.7 Wire Conductors
NSN: Size: Length:
NSN: Size: Length:
NSN: Size: Length:
C.3.8 AC Loads
6 145-2 1-900-7350 00 AWG f O feet 6 145-0 1 - 1 17-9792 4 AWG 70 feet 6 145-00-4 14-3297 12 AWG 25 feet
-- -
C3.9 Portable AC Cenerator
Output: 115 V,,
Load
A Mode1 No.
1
B Mode1 No.
r
3-Phase Breaker I
0239
0237
C
Phase A 1 Phase B Phase C
AVTRON Load Bank
L (mH) 2 @ 10.0 195530 30.0 19SP5
R(R) 12.8 0264 50.0 8365
R(Q 12.8 0264 50'0 8367
L (dl) 2 @ 10.0 195520 30.0 195PS
L (mR) 1 R(S2) AVTRON Load
Bank 30.0 195PS
50.0 8364
Appendix D AVTRON Laboratory Model and Aircraft Trial Photographs
Photograph D.1- AVTRON Model Generator Sensor Connections on AC Bos
Photograph D.2 - AVTRON Model Recording Equipment Setup
D-1
Photograph DJ - AVTRON Model TRU Sensor Connections on DC Bus
Photograph DA - AVTRON Model 9kW DC Load
Photograph D.5 - AVTRON Model Load A a Phases B & C"
Photograph D.6 - AVTRON Model Load B
Photograph D.7 - AVTRON Model Load D
Photograph D.8 - Ahraft Trial Recording Equipment Setup
Photograph D.9 - Aircnft Trial Distribution Panel AC Bus Connections
Photograpb D.10 - Aircraft Triai ThmePhase AC Bus Cumnt Connections
Photopph D.11- Aireraft Trial TRU DC Voltage and Current Connections
Appendix E
Aircraft Electrical Load Checklist
Aircraft Scenario No. 1
Table E.1- Essential Branch AC Load Checktist
I Case No. I
I , i ARC-SOSKFNO. 1 1 1 1 I
1 OFF 1 OFF 1 ON 1 ON
1
AC Loads 1 1 Hydradic Aux Pump Idle - 2 1 Fuel Boost Pump No. 2
1 ' 1 ~ransmit - 1 OFF 1 OFF 1 OFF 1 ONjOFF 1 4 1 AN/ARN-504 TACAN
I I 1 I 1
1 OFF 1 OFF l ON 1 ON
L
Staîus ON ON
Status ON ON
5 6 7 8 9 1 1 10
Status ON ON
12 1 3
1 16 1 URT 26 FDRKPI 1 1 1 1 I
1 OFF 1 ON 1 ON I ON
Status ON ON
1
C-12CompassNo. 1 BtNo.2 Flight Director No. 1 & No. 2 Propeller Synchrophaser Instrument Lighting (146) Hydradic Suction Pumps No. 1 & No. 2
Note: Loads not considered: - Propeiier Feather Pumps. - Aileron, Elevator, and Rudder Trim Tab Actuaton.
OFF OFF
AN/APN-150 Low Range Altimeter HSI No. 1 & No. 2
~ b ~ 5 0 9 Omega APN-50 1 A Doppler
' 14 ' AYN 50 1 ~o&ter
OFF OFF OFF OFF OFF OFF OFF
15
ON ON
OFF OFF
ANIARN-67 Giideslow No. 1 & No. 2
I
ON ON
OFF OFF OFF OFF OFF
ON ON
OFF OFF
ON ON
ON ON
OFF OFF
ON ON ON ON ON
ON ON ON ON ON
ON ON
ON ON
Aircraft Scenario No. 1 (cont'd)
Table E.2 - Essential Branch AC Load ChecWist UAC Instruments and Enghe Fuel Control Busn
I Case NO. 1
AC Loads
25
26 27 28
1 Statu OFF OFF OFF OFF OFF OFF OFF OFF
17 18 19 20 2 1 22 23 24
29
Liquid Oxygen Indicator Engine Temp Control Amplifier (4) Engine Torquemeter (4) Turbine Inlet Temp Indicator (4) Fuel Quantity Indicator (1 6) Fuel Quantity Totalizer Fuel Flow Transrnitter (4) Fuel Flow indicator (4)
2 Status OFF OFF OFF OFF OFF OFF OFF OFF
Hydraulic Pressure Indicator 1
Boost& Emergency Brake (2)
I 1
3 S t a t u ON ON ON ON ON ON ON ON
ON I
OFF
ON Hydraulic Pressure, Rudder BOOS~, Utility, Normal Brake and Ramp Indicator (51
4 Status ON ON ON ON ON ON ON ON
ON ON ON
OFF
ON
ON
ON ON
OFF
OFF OFF
Oil Pressure Indicator (Nos. 1 & 2) Oil Pressure Indicator (Nos. 3 & 4)
OFF
OFF OFF
Fuel Pressure Indicator OFF OFF ON
Aircraft Scenario No. 1 (cont'd)
Table E.3 - Essential Branch DC Load Checklist
I Case No. 1 I f
1 DC Loads ( Status [ Statw 1 Status Status
55 i Fuselage Lights (2) 1 OFF 1 ON 1 ON 1 ON
K
' 3 1 32 33 34 35 36 3 7 38 39 40 4 1 42 43 44 45 46
47
48 49 50 51 52 '
53 54
Note: ON* for one minute d u ~ g the five mioute recording penod.
30 Rudder High Boost Diverter (Flaps Down) (2) OFF
- - -
' A*& Of Attack Angle Of Attack Indicator Light Angle Of Attack De-Icing Control Angb Of Attack De-Ice Oil Cooler Flaps Pos Indicator (4) Landing Gear Pos Indicator (3) Anti-Ice Air Temp Indicator (6) Oil Temp Indicator (4) Oil Quantity Indicator (4) Flight Director System Gyros (2) Encoding Altirneter Copilot Altheter Emergency Brake
ON ,
ON
OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF ON
ON
Pitot Tube Heater (Pilot) [ OFF Prop De-Ice Timer 1 OFF
1
OFF OFF OFF OFF ON ON ON ON ON ON ON ON ON
I
Cargo Cornpartment Blower Motor (2) Ice Detecton (2) Standby - Operate - Oil Cooler Flap Actuator (4) Tai1 Lights (Navigation) (2) Wing Tip Lights (Navigation) (2) Flasher Lmding Lights (2) Glareshield Lights (5) Anti-Collision Lights (2)
OFF OFF ON
ON ON ON ON ON ON* ON ON
OFF OFF OFF
ON* ON* ON
ON ON
' ON ON ON
ON* ON ON
OFF
OFF
ON OFF OFF OFF OFF OFF OFF
OFF OFF OFF
ON* OFF ON
ON ON ON ON ON ON* ON ON
OFF ON ON ON ON ON ON ON ON ON
1 OFF ON ON ON ON ON ON ON ON ON
Aircraft Scenario No. 1 (cont'd)
Table E.3 - Essential Branch DC Load Checklist (cont9d)
I Case NO. I
1 59 1 TACAN AN/ARN-504 1 I
1 OFF 1 ON 1 ON 1 ON 1 1 60 1 URT 26 FDWCPI
I 1 I 1 1
1 OFF 1 ON 1 ON I ON 1
56 ' 57 r
58
OFF ON OFF
Emergency Exit Lights (2) TRU Bleeder Resistors (2) ARC 505 HFNo. 1
61 62
1 67 1 ARC 164 UHF Radio 1 1 1 L I
I OFF 1 ON 1 ON 1 ON 1
ON ON ON
63 64 65 66
ARN-509 Omega ARC-51 1 VHF
ON ON ON
KY5024 Selcal Decoder (2) ANIAPN-150 Low Range Altimeter APN-501 A Doppler APX-77 IFF
ON ON ON
I
OFF OFF OFF OFF
ON ON
OFF OFF
ClN ON
ON ON ON ON ON ON
ON ON ON ON
ON ON ON ON
Aircraft Scenario No. 2
Table E.4 - Main Btanch AC Load ChecMist
I Case NO. I
1 75 1 ANIAPN-59E Search Radar I 1 1
1 OFF 1 ONIOFF 1
AC Loads
Note: Loads 69 to 72 not tumed ON during trial. No fuel in extemal and awciliary hel tanks.
L
Status ON OFF
68 69
L E - - -
Statu I
ON OFF
Fuel Boost Pump No. 3 LH Aux Boost Pump
73 74
ON ON
OFF OFF OFF
70 71 72
ANIAPN- 1 33 High Range Radar Altimeter ARA-25 UHF/DF
ON ON
RH Aux Boost Pump LH Ext Pump (Mt) RH Ext Pump (M)
OFF OFF OFF
Aircraft Scenario No. 2 (cont'd)
Table ES - Main Branch DC Load Checklist
I Case NO. 1
Note: ON* for one minute during the five minute recording period.
DC Loads Status ON ON ON ON ON ON ON* ON ON ON ON ON ON ON ON ON ON ON ON ON OFF ON ON ON
76 77 78 79 80 8 1 82 83 84 85
Status ON ON ON ON ON ON ON* ON ON ON ON ON ON ON ON ON ON ON ON ON OFF ON ON ON
Wing Flap Ind Trim Tab Pos Ind "Rudder" Trim Tab Pos Ind "Elevator" Trim Tab Pos Ind "Aileron" Free Air Temp Ind (2) Anti-Skid System Window Heater Control Box (2) Cargo Area Floor Lights (1 3) Oxygen Regulator Lights (10) Dome Lights (Red) (30)
86 1 Mech & Nav Utility Lights (2) 87 88 89 90 91 92 93 94 95 96 97 98 99
Overhead Panel Lights (158) & (6) Pilot Circuit Breaker Panel Lights (78) Pedestal & Piiot Side Panel Lights (91) Formation Lights (9) TaxiLights (2) Navigator Instrument Panel Lights (70) Copilot Side & Circuit Breaker Panel Lights (78) Flight Station Lights (Clear) (8) Passenger Waming Signs (2) W indshield Wipers (2) Signal Light AN/ASQ-14 Radar Press TRU Bleeder Resistors (2)
Appendix F Simulation Mode1 Input Data File * File: AVTCASE.DAT * Condition: Taxi t+t+++++f+*+**+++++f**.*+***i. .t**** Time tard t *~+ *++++*+ t *+ f+ f+ * * * * * * t .
0.00005 . 4 7 5 1 O 1.OE-2010 O O0 * * + * * * * * * + * ~ * * * * * * * * ~ * * * * + * * * * * * * * * * * * * * * * * * * * ~ * * * * * * * * * * * * * * * * ~ * * * * * * * * f *++* *+*++++f f++** * t . t * * * * f Distribution Conductors *++*+t . *++*++f**"*
ir
A0 Al .O1848 ,0211 00 B1 A0 Al CO Cl A0 Al
+ ~ * i * + * t * + + + + + + * * * * + + * * f * * * f f * * AC Branch Loads * * * * * * + * + + + + C + * + + * * * * *
4
+ Load A - "Essential Branch Load" C
AACLD 2.460 BACLD 5. O CACLD 5.0 AACLD 5.560 BACLD 12.8 CACLD 12.8
4
* Load B - "HF Radio" * * AHFLD 30,O + BHFLD 30. O * CHFLD 30.0
AHFLD 39.67 * BHFLD 39.67 * CHFLD 39.67 4
Load C - "Main Branch Load" *
AACLD BACLD CACLD AACLD BACLD CACLD
* * Load D - "Search Radar" *
AHE'LD * AHE'LD 10.60
Bank- 2
Bank- 1
DCLD 1SBT DCLD 1SBT lSNYY ISBT l S N D Y
f
*<<<<<<<<<<<<<<<<< TRU-2 >>>>>>>>>>>>>>>>>> f
DCLD 2SBT 0,0001 0.112 DCLD 2000.0 2SBT SSNYY 0.0001 2SBT SSNDY 0.0001
* * + + + + + + + * + + + + * + * f * + + TRU-1 Wye-Wye Transfomer Windings * f f * f f * * * * * * *
(read from f i l e D:\MT32\CASE\trulyyCtrf) (saved in to file D:\MT32\CASE\trulyy,trf) Shunt branch for magnetizing l o s s e s lA3 lNYP 0.1109790210E+04 153 1NYP 0.1109790210Et04 1C3 lNYP 0.1109790210E+04
Coupled branch matrix Shunt branch for magnetizing l o s se s lXYY lSNYY 0,1299027972E+02 lXYY 1D2 0.1299027972E+02 lXYY 1D1 0.1299027972E+02 Coupled branch matrix Shunt branch for magnetizing lo s ses lYYY l D 5 0.1299027972E+02 lYYY lSNYY 0.1299027972E+02 1YYY ID6 0.1299027972E+02 Coupled branch matrix Shunt branch for magnetizing lo s ses lZYY lZYY 1ZYY Coup
l A 3 lXYY
104 1D3
lSNYY ed bra lNYPI lSNYY
nch mat NVERSE
lYYY 1DS
lYYY ID6
rix
0.1000000000E-02 0.5351076198E+05 0.0000000000E+00-0.4661974472E+02 0.0000000000E+00-0.2653962630E+05 0.0000000000E+00-0.265396263OE+05 0.1000000000E-02 0.5351076198E+05
t
++++++t++++++++i+++* TRU-2 Wye-Wye Transfomer Windings ~ * * * * + * * * * * * * +
* ( r e a d fxom file D:\MT32\CASE\tru2yy.trf) + (saved i n t o file D:\MT32\CASE\tru2yyDtrf) * Shunt branch for magnetizing losses 51 2A3 2NYF 0,1109790210E+04 51 2B3 2NYP 0. 1109790210E+04 51 2C3 2NYP 0.1109790210E+04 * Coupled branch rnatrix * Shunt branch for rnagnetizing losses 51 2XYY 2SNYY 0.1299027972B+02 51 2XYY 2D2 0.1299027972E+02 51 2XYY 2D1 0.1299027972E+02 * Coupled branch matrix + Shunt branch for rnagnetizing losses 51 2YYY 2D5 0.1299027972E+02 51 2YYY 2SNYY O.l299027972E+O2 51 2YYY 2D6 0.1299027972E+02 * Coupled branch matxix * Shunt branch for magnetizing losses 51 2ZYY 2D4 0.1299027972E+02 5 1 2ZYY 2D3 0.1299027972E+02 51 2ZYY 2SNYY 0.1299027972E+02 + Coupled branch matrix
0.0000000000E+OO-0.2653962630E+05 0.0000000000E+00-0.265396263OE+O5 0.1000000000E-02 0.5351076198E+05
* + + t + + + + + + * + * * ~ t + t + + + TRU-1 Delta-Wye Transfomer Windings * * '++*+*** * * 4
(read from file D:\MT32\CASE\truldy.trf) (saved into file D:\MT32\CASE\truldy.trf)
* Shunt branch for magnetizing losses 51 1A3 1B3 0.2944785276E+04 51 183 1C3 0.2944785276E+04 51 1C3 1A3 0.2944785276Et04
Coupled branch matrix * Shunt branch for magnetizing losses 51 lXDY 1SNDY 0.1139638037E+02 51 lXDY I D 1 2 O.U39638037E+02 51 lXDY ID11 0.1139638037E+02 + Coupled branch matrix
Shunt branch for magnetizing losses 51 lYDY I D 9 0.1139638037E+02 51 lYDY lSNDY O.I139638037E+02 51 lYDY ID10 011139638037E+02 * Coupled branch matrix + Shunt branch for magnetizing losses 51 lZDY ID8 0.1139638037E+02 51 lZDY ID7 011139638037E+02 51 1ZDY lSNDY 0.1139638037E+02
Coupled branch matrix 51 lA3 IB3INVERSE O.L500000000E+00 0.6196511800E+01 52 l X D Y lSNDY 010000000000E+00-0.3319398431E+02
O.1OOOOOOOOOE-02 0.2221601884E+05 53 lYDY ID9 0,0000000000E+00-0.3319398431E+02
0~0000000000E+00-01r084101473&+05 0~1000000000E-02 0.2221601884E+05
54 1ZDY ID8 0,0000000000E+00-0.3319398431&+02 0.0000000000E+00-0.108410L473E+05 0.0000000000E+00-O.r084101473E+05 011000000000E-02 0.2221601884E+05
51 183 IC3INVERSE 0.1500000000E+00 0.6196511800E+01 52 lXDY ID12 0,0000000000E+00-0.331939843W2
O.1OOOOOOOOOE-02 0.2221601884E+05 53 lYDY 1SNDY 0,0000000000E+00-0.3319398431E+02
0.0000000000E+00-0.1084101473E+05 011000000000E-02 0,2221601884E+05
54 lZDY 1D7 0.0000000000E+00-0,3319398431E+02 0,0000000000E+00-0,1084101473E+05 0.0000000000E+00-0.1084101473E+05 0.1000000000E-02 0,2221601884E+05
51 1C3 lA3INVERSE 0.1500000000E+00 0.6196511800E+01 52 lXDY lDl1 0.0000000000E+00-0.3319398431E+02
O.1OOOOOOOOOE-02 0.2221601884E+05 53 lYDY ID10 010000000000E+00-0.3319398431E102
0.0000000000E+00-0,1084101473E+05 0.1000000000E-02 0,2221601884L+05
54 l Z D Y lSNDY 0.0000000000E+00-0.331939843W2 0.0000000000E+00-0.1084101473EtO5 0.0000000000E+00-0.I084101473Ei05
0,1000000000E-02 0,2221601884E+05 * +t++++++++++++++++++ TRU-2 Delta-Wye Transformer Windings ++*++*++*+*+
* * (read from f i l e D:\MT32\CASE\tru2dy.trf) * (saved i n t o file D:\MT32\CASE\truîdy.trf) * Shunt branch for magnetizing losses 51 2A3 2B3 0.2944785276E+04 51 2B3 2C3 0.2944785276E+04 51 2C3 2A3 O .2944785276EtO4 + Coupled branch matrix * Shunt branch for magnetizing losses 51 2XDY 2SNDY 0,1139638037E+02 51 SXDY 2D12 0.1139638037Et02 51 2XDY 2Dll 0.1139638037E+02 * Coupled branch rnatrix + Shunt branch for magnetizing losses 51 2YDY 2D9 O.L139630037E+02 51 2YDY 2SNDY 0.1139638037E+02 51 2YDY 2DlO 0.1139638037€+02 * Coupled branch matrix + Shunt branch for magnetizing losses 51 2ZDY 2D8 0.1139638037E+02 51 2ZDY 2D7 O.L139638037E+02 51 2ZDY 2SNDY 0.1139638037E+02 * Coupled branch matrix
2 ZDY 2SNDY
* + TRU-1 Shunt Resistors +r
* TRU-2 Shunt Resistors *
$ = = End of level 1: *
Linear and nonlinear elements = = = = = = = = =
* * TRU-1 Diodes * -1 ID1 -L 1 D2 -1 lD3 -1 1D4 -1 ID5 -1 ID6 -1 lD7 -1 1D8 -1 ID9 -1 ID10 -1 lDll -1 ID12 * * TRU-2 Diodes * -1 2D1 -1 2D2 -1 2D3 -1 2D4
* AC Load * * A l AACLD -1 1 .0 0.0 * E l BACLD -1 1 .0 0.0 * Cl CACLD -1 1 0 0 .0 * + HF Radio
* Al AHFLD 0 . 3 0.4 4.5 * B 1 BHFLD 0 . 3 0.4 4 .5 * C l CHFLD 0 . 3 0 .4 4 .5 * * Search Radar * * Al AHFLD 0 . 3 0.4 4.5 1,OE-09 * $ = = = End of level 2: Switches and piecewise l i n e a r elements = = = = i,
* . . . S,M. Node Names for Armature Windings BO 0.04 0.1991858
t
* . S.M. Node Names f o r Armature Windings
* . . S.M. Impedances and T i m e Constants O .O23644 0.1018 2 ,5020 2.3267 O . 2903 O . 222094
0,400769 * * . . . S,M, Impedances and T i m e Constants
0.153467 0 .0 0.001999 0,006423 0,0134 9.0 0 . 0 * 00000000000 $> > >End of Synchronous machine data markerc < $ = = = End of l e v e l 3 : Sources = = = = = = = = = = = = = = = = = = =
**+*f+fff*+*++**++*****ff* .**:* Node Voltage Output t+*t f ***********+**
