Accionamientos Para Buques2
description
Transcript of Accionamientos Para Buques2
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Frequency ConvertersFrequency Converters
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Schematics of an AC VSD with DC LinkSchematics of an AC VSD with DC Link
Rectifier(AC to DC)
Inverter(DC to AC) Motor
Controller
Controls signals Measurements
Interface to control systems, commands and monitoring
Network DC Link Motor supply
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Control of Power SemiconductorsControl of Power Semiconductors
ON OFF
ConductionLosses
SwitchingLosses
Off-stateLosses
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Power SemiconductorsPower SemiconductorsUncontrolled devicesUncontrolled devices
The diode is an uncontrolled device. The diode is an uncontrolled device.
It will conduct current if positively biased, and block for currIt will conduct current if positively biased, and block for currents when ents when negatively biased, depending on the surrounding conditions.negatively biased, depending on the surrounding conditions.
u
i+u-
iu
i
symbol ui char. ideal analogy
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Power SemiconductorsPower SemiconductorsTurnTurn--on controllable deviceson controllable devices
The thyristor is a device that without a gate firing signal willThe thyristor is a device that without a gate firing signal will block currents in both block currents in both directions. If positively biased and in blocking mode, a gate fidirections. If positively biased and in blocking mode, a gate firing signal (current ring signal (current pulse) is given, the thyristor will conduct until the surroundinpulse) is given, the thyristor will conduct until the surrounding circuits force the g circuits force the current to reverse. The thyristor will then enter blocking mode current to reverse. The thyristor will then enter blocking mode by itself, until by itself, until positively biased and a new gate firing signal is given.positively biased and a new gate firing signal is given.
u
i+u-
iu
i
symbol ui char. ideal analogy
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Power SemiconductorsPower SemiconductorsTurnTurn--on and turnon and turn--off controllable devicesoff controllable devices
The transistor is the most known component. The transistor is the most known component.
If positively biased, the transistor can be turned on from a bloIf positively biased, the transistor can be turned on from a blocking condition by cking condition by giving a continuous gate firing signal. If removing the gate firgiving a continuous gate firing signal. If removing the gate firing signal, the transistor ing signal, the transistor will rewill re--enter blocking mode, even if positively biased. A transistor is enter blocking mode, even if positively biased. A transistor is normally not normally not designed to tolerate negative voltage bias, unless special considesigned to tolerate negative voltage bias, unless special considerationsderations
u
i+u-
iu
i
symbol ui char. ideal analogy
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Variable Speed Drives (VSD)Variable Speed Drives (VSD)
The most commonly used converters for motor drives are: Voltage source inverter (VSI) type converters
for AC motors, normally asynchronous motors Cycloconverters (Cyclo) for AC motors,
normally for synchronous motors Current source inverter type (CSI) converters
for AC motors, normally synchronous motors DC converters, or SCR (Silicon Controlled Rectifier)
for DC motors
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DC MotorDC Motor
DC
+-
R
E=nxIfxke
n +Ua-
Ua=E+RxIa
Ia
Ia
n
Ua
E
RxIa
Ua,max
If,maxIf
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Control Strategies for AM (IM)Control Strategies for AM (IM)
Scalar ControlScalar Control Rotor Flux Vector ControlRotor Flux Vector Control Stator Flux Vector ControlStator Flux Vector Control
Vs
n : 1
Rs Ls Rr / sLr
LmRm Vs
Rs Ls Lr
LmRm
Rr / s* *
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AC MotorAC Motor
AC
+-
R
E=nxxke
n +ua-
Ua=E+(jL+R)xIa= E+(j2fL+R)xIa =E+(j2PnL+R)xIa
ia
Ia
n
Ua
E
(jL+R)xIa
Ua,max
maxL
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DOL Asynchronous MotorDOL Asynchronous Motor
Speed
Slip1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0
10.90.80.70.60.50.40.30.20.10 snn
s
s
nnn
Stator current
TorqueLoad curves- full pitch- zero pitch
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DC Drive DC Drive (SCR (SCR -- silicon controlled rectifier)silicon controlled rectifier)
PM
cos = 0...0.96constant current
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CSI Drive and Synchronous motorCSI Drive and Synchronous motor
PM
six-step waveformcos = 0...0.96
constant current
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Cycloconverter and Synchronous MotorCycloconverter and Synchronous Motor
PM
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Voltage Source Inverters (VSI)Voltage Source Inverters (VSI)
PM
cos = 0.95 (constant)
constant voltage
near sinusoidalcurrents
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DOLasynchronousmotor + CPP
SCR DCmotor drive
Cyclo- 1
converterCSI (LCI) 2 VSI PWM 3
Start-up amps Typ. 5 x ratedcurrent
0(transformer
inrush)
0(transformer
inrush)
0(transformer
inrush)
0(transformer
inrush)Start-up torque transients Typ. 2-3 x
rated torque 0 0 Up to 50% of
rated torque 0
Power consumption, lowthrust
15% ofnominalpower
0 0 0 0
Amps at low thrust 45-55%of nominal
F(torque) F(torque) F(torque) 0
Power Factor - full load 0.85 > 0.9 > 0.76 > 0.9 > 0.95
Power factor variation withload (cos)
0.15 .. 0.85(non-linear)
0 .. 0.9(prop. speed)
0 .. 0.76(prop. speed)
0 .. 0.9(prop. speed)
> 0.95( constant)
Dynamic response (power,torque)
3-5 sec(pitch control)
< 100 ms < 100 ms Slower < 50 ms
Torque ripple None Smooth Smooth Pulsating SmoothZero-thrust crossing Smooth if
negative thrustallowed
Discontinuous Smooth Pulsating Smooth
Efficiency at full load High Lower High High HighHarmonic distortion:- at low speed /thrust- at full speed /thrust
NoneNone
F(torque)F(torque)
F(torque)F(torque)
F(torque)F(torque)
0F(power)
Short circuit contribution Typ. 5 xnominalpower
No No No No
Motor matching required - Some Some Yes NoCommutator No Yes No (sliprings) No (sliprings) No
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1212--pulse Rectifierpulse Rectifier
Vdc =2x1.35xVll
Ddytransformer
Vdc =1.35xVll
Series connection Parallel connection
Ddytransformer
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Harmonic distortion, 12Harmonic distortion, 12--pulsepulse11kV line-line voltages 11kV line currents
1750V line currents 1750V D-winding currents
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Pulse Width Modulation
Generation of ONGeneration of ON--OFF signalsOFF signals
0 5 10 15 2
OnOff
Upper and lower switchingelements are switched in opposite orders:- ON: Upper = on, Lower = off- OFF: Upper = off, Lower = on
0 5 10 15 20 5 10 15 20 5 10 15 2
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Pulse Width ModulationPulse Width Modulation
a
b
b-a
PM
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ThreeThree--level, Zero Voltage Clampedlevel, Zero Voltage Clamped
Vdc/2
Phase 1
+
0
_
Phase 2 Phase 3
Vdc/2
+
0
_
Phase
+
0
_
Phase
+
0
_
Phase
+
0
_
Phase
+
0
_
Phase
+
0
_
Phase
Positive Current:
Negative Current:
a) b)
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Motor Voltage, Current, TorqueMotor Voltage, Current, TorqueTorque
Line to line voltage
Current
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Simulation and Control DiagramSimulation and Control Diagram
Speedcontrol
PI
Torquelimitation
Speedlimitation
Speedreference
Torquereference
Torquecontrol loop
Speed
Torquereference
1
1 + Ts
Torque
1
J s
Motorinertia
KpTiS
(1 + Tis)
Loadcurve
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Operation Boundaries VSD IM(AM)Operation Boundaries VSD IM(AM)
Constant torqueregion
Field weakeningregion
RPM
Magnetic flux level
Maximum torque boundary
Maximum stator current boundary
Stator voltage
Stator frequency
Pitching momentlimitation
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Operation Boundaries VSD IM(AM)Operation Boundaries VSD IM(AM)
Constant torqueregion
Field weakeningregion
Speed
Maximum torque boundaryBollard Pull, V=0
Sailing, V>0
RPM
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Quadrants of OperationQuadrants of Operation
Speed
Torque
P0
P>0 P0, Torque
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Power SemiconductorsPower Semiconductors
IGBTLow voltage
IGCTMedium voltage
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690V Motor drive for AM(IM)690V Motor drive for AM(IM)
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3.3kV Motor drive for AM(IM)3.3kV Motor drive for AM(IM)
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HarmonicsHarmonics
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HarmonicsHarmonicsAll periodic waveforms can be expressed as a sum of a All periodic waveforms can be expressed as a sum of a series of sinusoidal functions with frequency equal to the series of sinusoidal functions with frequency equal to the multiple of the fundamental frequency, i.e.:multiple of the fundamental frequency, i.e.:
...)sin(
...)3sin()2sin(
)sin()(
1
313
212
11
+
++
+
++
++
+
=
hh
dc
thu
tutu
tuutu
-150
-100
-50
0
50
100
150
0 8 16 24 32 40 48 56 64 72 80 88 96 104
112
120
128
136
144
152
160
168
176
184
192
200
208
216
224
232
240
248
256
264
272
280
288
296
304
312
320
328
336
344
352
360
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Ideal current waveforms, Ideal current waveforms, large inductorlarge inductor
Vdc = 1.35xVll
6-pulse 12-pulse
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Example Example -- square wavesquare wave
-15
-10
-5
0
5
10
15
0 8 16 24 32 40 48 56 64 72 80 88 96 104
112
120
128
136
144
152
160
168
176
184
192
200
208
216
224
232
240
248
256
264
272
280
288
296
304
312
320
328
336
344
352
360
h=1h=5
h=7h=11
h=13
)37sin(3710...)35sin(
3510...
)7sin(7
10)5sin(5
10)sin(10)(
11
311
1
tt
tt
ttu
+++
+
+++
=
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Harmonic DistortionHarmonic Distortion
,...,,,h,..,,nxnh
1311752116
===
,...25,23,13,11,...2,1,112
===
hnxnh
6-Pulse
12-Pulse
)1(
2
2)(
%100i
iTHD h
h==
0 %
5 %
10 %
15 %
20 %
25 %
1 2 3 4 5 6 7 8 9 10 11 12
Ih(6-p)Ih(12p)
5 7 11 13 17 19 23 25 29 31 35 37
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Harmonic AnalysisHarmonic Analysistwo different methodstwo different methods
Frequency domain calculationFrequency domain calculation Harmonic current injection and impedance modelsHarmonic current injection and impedance models Easy to build up large systemsEasy to build up large systems Short calculation times, also with large systemsShort calculation times, also with large systems Need accurate harmonic spectrum and modelsNeed accurate harmonic spectrum and models
Time domain calculationTime domain calculation Circuit diagramCircuit diagram modellingmodelling Complicated to build up large systemsComplicated to build up large systems Time consuming to simulate large systemsTime consuming to simulate large systems Calculates accurate harmonic spectrum withCalculates accurate harmonic spectrum with
proper modelsproper models
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Example Power SystemExample Power System
Vessel Loads
Propulsion Auxilliaries
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Single LineSingle Line
G G G G
M M
M M M
MMMM
M
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Impedance model for Impedance model for harmonic current injection modelharmonic current injection model
10
1m
1m
2m
10 1m
1m
0.5m
10m
3m
2m
1mv_sin
Harm load 1
Load 1
Load 2
Load 3
Generator 1
Cable 1
3m
2m 2m
2m
Trafo 1
2m
v_sin
Bus 1
Bus 2
Load 4
101m
0
1
2
3
4
5
6
7
8
9
10
2 4 6 8
1
0
1
2
1
4
1
6
1
8
2
0
2
2
2
4
2
6
2
8
3
0
3
2
3
4
3
6
3
8
4
0
4
2
4
4
4
6
4
8
5
0
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Circuit model for time simulationCircuit model for time simulation
EL R
EL R
EL R
EL R
EL R
EL R
R
EL R
EL R
EL R
L R
L R
L R
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Harmonic distortion, 12Harmonic distortion, 12--pulsepulse11kV line-line voltages 11kV line currents
1750V line currents 1750V D-winding currents
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Current and Voltage Distortion, VSICurrent and Voltage Distortion, VSI
Approx8% THD
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Theoretical vs. real 12pTheoretical vs. real 12p--harmonicsharmonics
0
1
2
3
4
5
6
7
8
9
10
2 4 6 8
1
0
1
2
1
4
1
6
1
8
2
0
2
2
2
4
2
6
2
8
3
0
3
2
3
4
3
6
3
8
4
0
4
2
4
4
4
6
4
8
5
0
1h
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ComparisonComparisonTime simulation Time simulation -- Injected harmonics (Injected harmonics (IIhh = 1/h)= 1/h)
0
1
2
3
4
5
6
7
8
9
10
2 4 6 8
1
0
1
2
1
4
1
6
1
8
2
0
2
2
2
4
2
6
2
8
3
0
3
2
3
4
3
6
3
8
4
0
4
2
4
4
4
6
4
8
5
0
Time sim.approx
8% THDv Inj. harm.approx
20% THDv
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Harmonic AnalysisHarmonic Analysistwo different methodstwo different methods
Frequency domain calculationFrequency domain calculation Harmonic current injection and impedance modelsHarmonic current injection and impedance models Easy to build up large systemsEasy to build up large systems Short calculation times, also with large systemsShort calculation times, also with large systems Need accurate harmonic spectrum and modelsNeed accurate harmonic spectrum and models
Time domain calculationTime domain calculation Circuit diagramCircuit diagram modellingmodelling Complicated to build up large systemsComplicated to build up large systems Time consuming to simulate large systemsTime consuming to simulate large systems Calculates accurate harmonic spectrum withCalculates accurate harmonic spectrum with
proper modelsproper models
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Managing HarmonicsManaging Harmonics
Generator design, Generator design, subtransient subtransient reactancereactance Selection of converter typeSelection of converter type Design of drive transformer / inductorDesign of drive transformer / inductor Passive filtersPassive filters Active filtersActive filters Clean power supplyClean power supply Selection of equipmentSelection of equipment Know your system!! Analysis and freq. scanKnow your system!! Analysis and freq. scan
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Generator Generator SubtransientSubtransient ReactanceReactance
Harmonic currents injected in the system Harmonic currents injected in the system distort the voltage on generator terminalsdistort the voltage on generator terminals Subtransient Subtransient reactance is found either as:reactance is found either as:
Average Average subtransientsubtransient reactance: (reactance: (xxdd++xxqq)/2)/2 Negative sequence reactance: xNegative sequence reactance: x--
Low Low subtransient subtransient reactance will increase reactance will increase generators dimensions, weight, and costsgenerators dimensions, weight, and costs
LowLow subtransientsubtransient reactance will increase reactance will increase short circuit currentshort circuit current
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Selection of Converter TypeSelection of Converter Type
Different topologies have different spectrumDifferent topologies have different spectrum VSI : low harmonicsVSI : low harmonics CSI : high harmonics, CSI : high harmonics, interharmonicsinterharmonics Cycle : wide band high high harmonicsCycle : wide band high high harmonics DC (SCR) : high harmonics, DC (SCR) : high harmonics, interharmonicsinterharmonics
Pulse number, i.e. 6, 12, 18, 24, 48,Pulse number, i.e. 6, 12, 18, 24, 48, Active front end (harmonicActive front end (harmonic--less design)less design)
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Current and Voltage Distortion, CSICurrent and Voltage Distortion, CSI
Approx10% THD
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1212--pulse Rectifierpulse Rectifier
Vdc =2x1.35xVll
Ddytransformer
Vdc =1.35xVll
Series connection Parallel connection
Ddytransformer
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Design of Drive TransformerDesign of Drive Transformer
Drive transformer or inductorDrive transformer or inductor High s.c. impedance reduces harmonicsHigh s.c. impedance reduces harmonics High s.c. impedance give a load dependent High s.c. impedance give a load dependent
voltage drop, and reduced max power outputvoltage drop, and reduced max power output
Use of ZUse of Z--winding in order to achieve winding in order to achieve quasi 24 pulse with two 12 pulse convertersquasi 24 pulse with two 12 pulse converters quasi 48 pulse with two 24 pulse convertersquasi 48 pulse with two 24 pulse converters
EMC: Grounded shield between EMC: Grounded shield between pripri. and sec.. and sec.
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Passive FiltersPassive Filters Passive filters are used to create a low Passive filters are used to create a low
impedance path for harmonic currents with a impedance path for harmonic currents with a serial resonanceserial resonance
Normally one or twoNormally one or two parallellparallell connected LC connected LC filters tuned to the frequency of the worst filters tuned to the frequency of the worst harmonic currents, e.g. for 12 pulse:harmonic currents, e.g. for 12 pulse: 11th harmonic (also efficient for 13th)11th harmonic (also efficient for 13th)
Warning 1: Parallel resonance occurs normally at Warning 1: Parallel resonance occurs normally at about 1/2 of series resonanceabout 1/2 of series resonance
Warning 2: Capacitive limit for generatorsWarning 2: Capacitive limit for generators
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Passive FilteringPassive Filtering
G G G G
M M
M M
MMMM
filter filter
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Passive FilteringPassive Filtering
L
C
First order undamped LC filter
Lg
Aggregated Generator / motor model
Z()
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Frequency Response Z(Frequency Response Z())
Generator2 . . f . Lg
Filter
Resulting
f / f1
Z
5 7 11 13
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Passive Filtering Passive Filtering -- two stepstwo steps
Z()
L
C
First order 5th harm undamped LC filter
Lg
Aggregated Generator / motor model
L
C
First order 3rd harmundamped LC filter
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Frequency response Z(Frequency response Z())
Generator2 . . f . Lg
Filter
Resulting
f / f1
Z
5 7 11 13
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Active FilterActive Filter
G
M
ActivefilterNon-
linear load
i1 i2
ig = i1+i2
1 3 5 7 9
1
1
1
3
1
5
1
7
1
9
2
1
2
3
2
5
2
7
2
9
3
1
3
3
3
5
3
7
3
9
4
1
4
3
4
5
4
7
4
9
5
1
5
3
5
5
5
7
5
9
6
1
6
3
6
5
6
7
6
9
7
1
7
3
7
5
7
7
7
9
8
1
8
3
8
5
8
7
8
9
igi1
i2
HF filter
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Clean Power SupplyClean Power Supply
Rotating ConverterRotating ConverterMotorMotor--GeneratorGenerator
Static ConverterStatic ConverterPWM converter PWM converter with HF filterwith HF filter
UPSUPSPWM converter with PWM converter with HF filter and battery HF filter and battery DC link backupDC link backup
Dirty net withhigh distortion
Rectifier(AC to DC)
Inverter(DC to AC)
Inverter(DC to AC)
Rectifier(AC to DC)
M G
Clean net without distortion
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Selection of Selection of EquimpentEquimpent
High tolerance for harmonic distortionHigh tolerance for harmonic distortion Uncompensated Uncompensated flouorescent flouorescent light, capacitive light, capacitive
compensators will be overloadedcompensators will be overloaded True RMS measurement circuits in protection True RMS measurement circuits in protection
devicesdevices Electronic rectifiers can be overloaded if high Electronic rectifiers can be overloaded if high
distortion, avoid sensitive equipmentdistortion, avoid sensitive equipment If necessary, local filtering or UPS supply.If necessary, local filtering or UPS supply.
Cheaper than overall filteringCheaper than overall filtering
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Impedance model for Impedance model for harmonic current injection modelharmonic current injection model
10
1m
1m
2m
10 1m
1m
0.5m
10m
3m
2m
1mv_sin
Harm load 1
Load 1
Load 2
Load 3
Generator 1
Cable 1
3m
2m 2m
2m
Trafo 1
2m
v_sin
Bus 1
Bus 2
Load 4
101m
0
1
2
3
4
5
6
7
8
9
10
2 4 6 8
1
0
1
2
1
4
1
6
1
8
2
0
2
2
2
4
2
6
2
8
3
0
3
2
3
4
3
6
3
8
4
0
4
2
4
4
4
6
4
8
5
0
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Frequency ScanFrequency Scan
102 103 104 1050
2000
4000
6000
8000
M
a
g
.
(
o
h
m
s
)
102 103 104 105
-100
-50
0
50
100
P
h
a
s
e
(
d
e
g
r
e
e
s
)
Frequency (Hz)
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Frequency ScanFrequency Scan
102 103 104 1050
0.5
1
1.5
2x 10 4
M
a
g
.
(
o
h
m
s
)
102 103 104 105-100
-50
0
50
100
P
h
a
s
e
(
d
e
g
r
e
e
s
)
Frequency (Hz)
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Transient OvervoltagesTransient Overvoltages
ResonanceResonance Faults (earth faults, short circuits)Faults (earth faults, short circuits) Switchgear operationsSwitchgear operations
OpenOpen inductive current interruptioninductive current interruption virtual choppingvirtual chopping restrikesrestrikes
CloseClose surge voltagessurge voltages prestrikesprestrikes
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Transient Overvoltage ManagementTransient Overvoltage Management
Equipment designEquipment design power frequency: power frequency:
dielectric dielectric strengthtstrengtht high frequency: high frequency:
impulse voltageimpulse voltage
ProtectionProtection Surge arrestersSurge arresters Surge capacitorsSurge capacitors