Facts&Compensators
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Transcript of Facts&Compensators
Application of FACTS in Indian Power System
Subrata Mukhopadhyay, Senior Member, IEEE, Ashok K. Tripathy, Senior Member, IEEE, V.K.Prasher, and Krishan K . Arya
Abstract-- Flexible AC Transmission System or in short FACTS is a technology-based solution envisioned to help the utilities deal with changes in the power delivery business. Its
role in enhancing the transfer capability of existing transmission system under steady state as well as improving system security
under dynamic contingencies has ushered in a new era. Inspired with the success of such ventures necessitated due to the right- of-way and other problems elsewhere in the world, in India a project has been undertaken on a 400 kV line between Kanpur (Uttar Pradesh) and Ballabhgarh (Haryana) in the Northern Grid. It has a 27% fixed and an 8% variable capacitor section. The latter can be raised to 20% through thyristor control. Power carrying capacity is envisaged to be increased from 400
to 600 MW.
The present paper gives details of project, planning studies, design parameters and project performance.
Zndex Terms- FACTS, HVDC, power electronics, reactive power, stability, thyristor, varistor
I. INTRODUCTION
Today, the electric industry faces awesome challenges: asset
utilization, requirement for transmission network.
Transmission constraints impact both economic interchange
and system stability. Construction of new transmission line
has become more difficult and expensive, with permitting and
Subrata Mukhopadhyay and Krishan K. Arya are with Central Electricity
Authority, Sewa Bhavan, R.K.Puram, New Delhi - 110066, INDIA (e-mail:
subrata(idieee.org, kkarya-2001 @rediffmail.cQrn)
Ashok K. Tripathy is with Bharat Heavy Electricals Ltd., Integrated Office
Complex, Lodhi Road, New Delhi - 110003, INDIA (e-mail:
trioathy~bhelindustrv.com)
V.K.Prasher is with PowerGrid Corporation of India Ltd., B-9 Qutab
Institutional Area, Katwaria Sarai, New Delhi - 110016, INDIA
licensing issues holding up system expansion for years. It is
very difficult to acquire new right-of-way (ROW). Increased
demand on transmission, significant deviation from planned
system and the need to provide open access to generating
companies and customers, all together have created
tendencies towards reduced security and poor quality of
supply. However, with more and more generation coming up
and requiring haulage of large amount of power over long
distance, it has become difficult to plan further system on
account of congestion, leaving practically no corridor. This
has lead to the development of several innovative means for
optimum utilization of ROW by enhancing the capability of
existing transmission system. To meet this goal, technology
like, Flexible AC Transmission System (FACTS) is a
possible solution towards enhancing loadability of lines.
The FACTS devices use high-power electronics to achieve
control and to increase the capacity of ac transmission
system, restriction only being the thermal limit. This can be
accomplished using a wide variety of methods employing
series or shunt controlled devices. There are numerous
references [l] - [5] which give details of the characteristics
of FACTS devices and they have their relative merits.
FACTS devices: Static Var Compensator (SVC)
Static Compensator (STATCOM) Thyristor Controlled Series Capacitor (TCSC)
Unified Power Flow Controller (UPFC) Inter-line Power Flow Controller (IPFC)
FACTS like devices are: High Voltage DC (HVDC) Phase Shifting Transformer Switched Capacitors (Series or Shunt) Switched Reactors (Series or Shunt)
0-7803-7525-4/02/$17.00 0 2002 IEEE. 237
Flexible AC Transmission System (FACTS) Technology is
an emerging technology for enhancing the capability of
existing transmission system. With the installation of
FACTS, it is possible to increase the power with small
additional investment and within short gestation period as
compared to building of additional lines. It enhances the
transfer capability of existing transmission system under
steady state as well as improves system security under
dynamic contingencies. The basic concept in different forms
has been widely attempted in North America. First SVC for
voltage control was demonstrated in Nebraska in 1974. To
give a few examples, there are TCSC of 202 MVAR at Slatt
500 kV Substation of Bonneville Power Administration in
Oregon [6], STATCOM at 161 kV Sullivan Substation of
Tennessee Valley Authority having capacity +/- 100 MVAR
set up in 1995 [7], UPFC of American Electric Power
Company at 138 kV Inez Substation (Kentucky) [8] with a
novel concept of controlling voltage, line impedance and
phase angle with a total rating of +/- 320 MVAR, IPFC (with
development in progress that will eventually enable more
flexibility in sharing of power through parallel lines too) at
345 kV Marcy Sub-station of New York Power Authority.
In India at the time of independence, the power supply
was essentially locally oriented and the highest system
voltage was 132 kV. Subsequently, it rose to 220 kV and
finally to 400 kV level. Also 800 kV transmission system has
been constructed, but charged at 400 kV level for operation at
present. There is wide gap between demand for power and
generated power and the growth rate of electrical energy
requirement is about 8% per annum. To keep pace with the
growing demand, the generating capacity addition proposed
by end of 9Ih Five Year Plan (1997-2002), loLh and 1lLh Plan
are about 40,000 MW, 55,000 MW and 60,000 MW
respectively. The construction of generating station and
associated transmission system is capital intensive with long
gestation period, Nevertheless, environmental and ecological
consideration and regulatory authorization process including
ROW problems are strongly limiting or delaying installation
of new facilities in the transmission network.
Under these circumstances, it is important to utilize
existing systems as efficiently as possible, to increase both
the capacity and the quality of present transmission networks,
even if for limited period, through various innovative
methods with minimum investment. Problems arising from
delays or difficulty to add new transmission facilities could
be partially or completely overcome by increasing the
flexibility of the existing network. Hence, possibility of
power flow control in AC transmission network is getting
more and more attractive. Flexible AC Transmission System
technology is an evolving technology based solution for
power transmission at small additional investment with a
short gestation period. FACTS has been defined by the IEEE
as “Alternating Current Transmission Systems incorporating
power electronics based and other static controllers to
enhance controllability and increase power transfer
capability”. Thus FACTS increases the flexibility of power
systems, make them more controllable and allow increased
utilization of existing network closer to its thermal loading
capacity without jeopardizing the stability. Based on the
experience gained by power utilities of world and system
studies conducted in India, a FACTS project has been
undertaken in September 2000 which is an in-house
development effort on 400 kV line between Kanpur (Uttar
Pradesh) and Ballabgarh (Haryana) in the Northern Grid.
The project is proposed to be implemented in two phases.
Phase-I covers commissioning of 35% Fixed Series
Compensation (FSC) consisting of two banks of 27% and
8%. Phase-I1 covers commissioning of Thyristor Controlled
Series Capacitor (TCSC), under an R&D project.
11. SCENARIO IN INDIA
It is well known that proper active and reactive power
management in an extensive electrical network can lead to
reduced system losses and improved voltage profile. By
judiciously applying series compensation, active power
transfer and reactive power consumption of the transmission
lines can be controlled.
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With the advantages envisaged, application of series
compensation on following 400 kV corridors were considered.
i) Itarsi-Indore double circuit line
ii) Satpura-Indore line
iii) Bhilai-Satpura line
iv) Bhilai-Chandrapur double circuit line
v) Bhilai-Satpura and Satpura-Koradi lines
vi) Vindhyachal-Jabalpur double circuit line
vii) Dadri-Malerkotla line
viii) Kanpur-Ballabhgarh line
Series compensation of 400 kV lines shows promising
results in terms of improvement in power hand!ing capacity of
lines and improvement in voltage profile together with system
loss reduction which pays back the cost of series
compensation scheme. Based on the results of system studies
and other technical and economical considerations a project
has been undertaken on a 400 kV Kanpur - Ballabhgarh line at
Ballabhgarh end in the Northern Grid. This is the first of its
kind. As so far Indian Engineers had the experience of
working with SVCs, both in power system and industrial
installations.
Power carrying capacity is envisaged to be increased from
400 to 600 MW. The controller so designed has features to
damp low frequency inter-area oscillations following outage
of a parallel AC line between Kanpur & Agra (also in Uttar
Pradesh) or one pole of parallel HVDC line at +/-500 kV.
Cases
Base case 35% series compensation in Agra-Ballahharh line 47% series compensatio* in Kanpur- Ballabhgarh line
Kanpur- Ballabhgarh
Outage of Kanpur-Agra
Outage of
111. PLANNING S'TUDIES
Power Flow (MW) Kanpur - Kanpur - Agra - Ballabhgarh Agra Ballabhgarh 351 474 24 1 490 461 184
566 398 199
599 31 1
588 142
Kanpur-Ballabhgarh and Kanpur-Agra lines in Uttar
Pradesh together carry about 800 MW power from Singrauli - Rihand mine-mouth generation belt to western part of Uttar
Pradesh and Rajasthan. Kanpur-Ballabhgarh is a 400 kV,
400 km single circuit line and Kanpur-Agra is 400 kV, 250
km single circuit line. Ballabhgarh and Agra are also
connected through a single circuit line which is generally
lightly loaded as it serves as a tie line between Kanpur-
I Cases
Ballabhgarh-Jaipur axis and Kanpur-Agra-Jaipur axis.
Power Flow (M W) I I Kanpur- I Arra- Kanwr -
t I Kanour-
Base case 35% series
Ballibhgarh 415 Base case
35% series 5 73
Ballabhgarh Agra Ballabhgarh 516 419 523 730 356 486
Cases Power Flow (MW)
Ballabhgarh
461 184 compensation in Agra-Ballabhgarh line 47% series compensatio* in Kanpur-
658
Ballabhgarh line Outage of Kanpur- Ballabhgarh line Outage of Kanpur-Agra line
TABLE I1 ANIA - I I & AUKAIYA - II TIMI: FKAMI: (2001 -2002)
I line
TABLE 111 RIIIANI)-II TIMI: FKAMIC (2003-2004)
compensation in Agra-Ballabharh I I line 47% series I 850 I 322 I 467
KanDur- I I I compensatio* in
Ballabhgarh line Outage of Kanpur- Ballabhgarh Outage of Kanpur- Agra
* operational for restricted time only
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Details of studies carried out by PowerGrid Corporation of
India Ltd. for this region show that the line after installation
of TCSC would help in preventing collapse of the grid under
similar situation experienced in the last two grid collapses in
the Northern Grid. Results of studies are summarized through
Table I, I1 and 111.
IV. DESIGN PARAMETERS
Phase-I covers design development, supply erection and
commissioning of Fixed Series Capacitor consisting of banks
of 27% and 8% with associated protection equipment. Phase-
11 covers design, development, supply, erection and
commissioning of thyristor controller for 8% series capacitor
bank of Phase-I to be converted to variable bank with range
from 8 to 20%. Project details and equipment parameters are
given in Appendix. Single Line diagram of TCSC scheme
is given in Fig. 1.
The broad parameters of main equipment are given below:
System parameters
Rated voltage Nominal reactive power Continuous effective impedance Maximum dynamic impedance Rated current Rated continuous voltage TCR inductance /phase
27% Capacitor bank
420 kV 15 1.6 Mvar
35.1 ohm 35.1 ohm
1200 A 42.2 kV
8% Capacitor bank
420 kV 79.87 Mvar
10.4 ohm 26 ohm 1600 A 16.6 kV 4.4 mH
v. PROGRESS IN IMPLEMENTATION
All equipment pertaining to Fixed Series Compensation have been completed and the system is likely to be charged in March 2002. Photographs depicting views of platform mounted equipment are shown in in Fig. 2 and 3.
VI. WORK TO BE DONE FURTHER
Under Phase-11, ratings of thyristor, TCR (thyristor controlled reactor) shall be finalized and design of their controllers shall be completed. These equipment shall be installed, erected and commissioned by October 2002.
8% 4PRVIBLE COMPENSATION r-b+-
LlhE cr PII cr 198
6"' f 2998- CS
FPOhr KAWJR ---
Fig. 1 . Single line diagram of TCSC scheme
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Fig. 2. Mounting on insulated platform
VII. CONCLUSION
With the installation of Fixed Series Capacitor immediately while loadability of a transmission corridor between eastern and western part of northern grid will increase, incorporation of TCSC further in this system will improve dynamic performance under various contingencies of operation and may avoid disintegration of grid as faced a number of times in the past.
VIII. APPENDIX
A. PROJECT DETAILS The broad parameters are as follows:-
Line length 390 km Type of conductor Line reactance 0.332 ohms/km Rated voltage 420 kV System frequency 50 Hz System short-circuit level
Twin ACSR Moose
40 kA for 1 s
B. SITE CONDITIONS
Maximum ambient temperature 48°C
Fig. 3. View over the platform
Minimum ambient temperature 1°C Altitude less than 1000 m Humidity 100 % Pollution Heavy Seismic acceleration 0.3g horizontal
C. EQUIPMENT PARAMETERS
In the series compensated schemes there are two types of equipment
Ground mounted Platform mounted
1) Ground Mounted Equipment:
Bypass circuit breaker
The bypass circuit breaker shall be provided for the following purpose:
a) Deliberate bypassing b) Bypassing through automatic protection c) Manual insertion
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d) Automatic re-insertion following line faults and [7] C. Schauder, M.Gernhardt, E.Stacey, T. Lemak, L. Gygugyi, T.W. Cease, and A. Edris, “TVA STATCOM Project: design, installation
and commissioning”, C E R E Meeting, Paris, August, 1996, Paper 14-106. [8] A.Edris, A. S.Mehraban, M.Rahman, L.Gyugyi, S.Arabi, and
T.Reitman, “Controlling the flow of real and reactive Power”, IEEE Computer Application in Power, vol. 1 1 , no. I , Jan 1998.
disturbances
Technical particulars of the circuit breaker
Rated voltage Rated current
420 kV 2000 A
Type of circuit breaker SF6 Duty cycle of mechanism c-0-c Technical particulars of disconnecting switch
420 kV, 2000 A, outdoor, triple pole. Both main switch earth switch are motor-operated.
2) Plalform Mounted Equipment:
Insulated platform
and
XI. BIOGRAPHIES
Subrata Mukhopadhyay (S’70, M’70, SM’80) was born in Asansol, India in 1947. He graduated in Electrical Engineering from Jadavpur University, Calcutta in 1968; had his Master’s and Doctorate Degrees from Indian Institute of Technology, Kharagpur and Roorkee in 1970 and 1979 respectively. His employment experience over 31 years includes teaching in Roorkee and power system planning, design and operation with the Central Electricity Authority of Government of India. He has authored two books and twenty one papers, won IEEE Third Millennium Medal in 2000 and is a Fellow of the Institution of Engineers (India).
-3 Single phase, galvanized steel platforms shall be provided in series capacitor bank installation. These platforms are independently supported on suitable number of 400 kV post insulators. Platform mounted main equipment are as follows:
Ashok K. Tripathy (M’98, SM2000) born in 1948, obtained Bachelor‘s and Master’s Degrees in Electrical Power from Regional Engineering College, Rourkela and Indian Institute of Science, Bangalore in 1969 and 1971 respectively. After a brief spell of working with
a) Capacitor bank the Steel Authority of India Ltd., he is working b) Sparkgap with the Bharat Heavy Electricals Ltd. for the
last 26 years in the field of series compensation c) and HVDC. He is the Project Director of National HVDC Project and a Member of Study
d) Metal Oxide Varistor Committee in CIGRE. His current interest e) Current transformers includes introduction of FACTS in Indian power
system. He is one of the Vice Presidents of the Indian EMTP User Group. €) Control & protection equipment
g ) Thyristor valves
Damping circuit (damping reactor+ damping resistor)
h) Thyristor controlled reactors
IX. ACKNOWLEDGEMENT
The project is being financed by Bharat Heavy Electricals Ltd., Ministry of Power, and Ministry of Communications and Information Technology of the Government of India.
The authors are indebted to their organizations Central Electricity Authority, Bharat Heavy Electricals Ltd. and PowerGrid Corporation of India Ltd. for the encouragement being received during the execution of the project.
X. REFERENCES
[ I ] N.G.Hingorani, “Flexible AC transmission”, IEEE Spectrum, vol. 30, no. 4, Apr. 1993.
[2] N.G.Hingorani, and L. Gyugyi, “Understanding FACTS concepts and technology of flexible AC transmission system”, Piscataway: IEEE Press, 1999.
[3] R.Adapa, “Summary of EPRl’s FACTS system Studies”, C E R E SC 14 International colloquium on HVDC & FACTS, Montreal, September, 199s.
[4] N.G.Hingorani, “Power Electronics in AC Transmission System“, CIGRE special Report 1996.
[SI K.R.Padiyar, and A.M.Kulkarni, “Application of static condenser for enhancing power transfer in. long ,AC lines”, C E R E Symposium on Power Electronics in Electric Power System, Tokyo, May 1995.
[6] V.Venkatasubramanium , and C.W.Taylor, “Improving Pacific intertie stability using Slatt thyristor controlled series compensation, detailed summary”, submitted to IEEE PES WM, Jan 2000, Singapore.
V.&Prasher having been graduated in Electrical Engineering in 1971 worked in the Electrical Design Groups of Central Electricity Authority and National Thermal Power Corporation Ltd. up to 1983. Thereafter, he took over as head of the HVDC Engineering Group in the Corporation and subsequently worked at site for ten years in the construction, testing, commissioning and then in operation and maintenance of Rihand-Delhi HVDC link. After absorption in the PowerGrid Corporation of India Ltd. he executed a number of EHV AC Substations and HVDC links. Presently he is in- charge of Load Dispatch, Communications and HVDC Departments. He is a regular member of Study Committee 14 of CIGRE on HVDC and Power Electronics.
Krishan K. Arya born in 1958, obtained his Bachelor’s and Master’s Degrees in Electrical Engineering from Delhi College of Engineering and Indian Institute of Technology, Delhi in 1979 and 1985 respectively. He is working in the Central Electricity Authority for the last 22 years in the area of power system design. His field of interest is in the area of design and engineering of EHV Substation, new technologies, like, development of HVDC, FACTS, etc.
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