MAGNETICALLY CONTROLLED SHUNT REACTORS

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HISTORY OF “ZAPOROZHTRANSFORMATOR”

1947 – 2009 1947 1949 1955

1960-1965 1962

1967

1970 1971

1972

1977

1978

1980

1981

1982-1985

1985 1988

1987-1990

1990 1996

1997 1998

1999

2000

2001 2002

2003 2005

2006

-Construction of the transformer plant was started in Zaporozhye -First transformer TM-1000 kVA, 10 kV was manufactured -Transformers 90000 kVA, 400 kV were manufactured for OHL Kuibyshevskaya HPP – Moscow -Autotransformers up to 250 MVA and transformers up to 400 MVA, 330 kV were designed -First three-phase autotransformer 250 MVA, 500 kV equipped with built-in OLTC device was manu-factured -Transformers and autotransformers 206 MVA and 167 MVA, 500kV were manufactured for Aswan HPS (Egypt) -Transformer 630 MVA, 220 kV (being of the highest power rate at that time) was manufactured for Krasnoyarskaya HPP (Russia) -Pilot transformer 210 MVA, 1140 kV was manufactured for 1200 kV AC line -Step up transformer 1000 MVA, 330 kV for generation unit 800 MW of Slavyanskaya TPP (Ukraine) was manufactured -Three-phase autotransformer 560 MVA, 330/110 kV was manufactured for Coventry substation (USA) -Single-phase autotransformers 333 MVA, 750/330 kV and 417 MVA, 750/500 kV were manufactured for transmission lines of new voltage level 750 kV -Three-phase transformer 1000 MVA, 330 kV was manufactured for Uglegorskaya TPP (Ukraine). It became one hundred thousand transformer since foundation of the plant -Transformer 667 MVA 1150/500 kV was manufactured -Step-up single-phase transformers 417 MVA, 750 kV were manufactured for generation units 1000 MW of NPC - Step-up single-phase transformers 533 MVA, 500 kV (total capacity of three units – 1600 MVA) were produced for doubled generation units 640 MW each of Sayano-Shushenskaya HPP (Russia) and for generation units 1200 MW of thermal power plants -1000 MVA, 500 kV transformer was manufactured for generation unit 800 MW of Ryazanskaya TPP (Russia) -Three-phase transformer with the highest power rate 1250 MVA, 330 kV for generation units 1000 MW of Yuzhno-Ukrainskaya NPP -Special equipment was developed for DC line 1500 kV, including converter transformer 320 MVA for the voltage levels ± 400 and ± 750 kV power winding 500kV -Single-phase unit transformer 417 MVA, 1150 kV was manufactured -Liner shunt reactor 1200 A, 800 kV was manufactured for 750 кV transmission line Ekibaztuz – Cen-ter (Kazakhstan) -Single-phase 333 MVA, 750 kV step-up transformer and three-phase 666 MVA, 500 kV step-up trans-former were manufactured -Shunt reactor 60 MVAr, 500 kV was manufactured. -Shunt reactors for 750 kV transmission lines in Ukraine, 400 kV and 500 kV transmission lines in Egypt were manufactured -First three-phase Magnetically Controlled Shunt Reactor 25 MVAr, 110 kV was designed. -Unit transformer 400 MVA, 220 kV with OLTC device was manufactured -Autotransformer 250 MVA with voltage regulation at 220 kV side was manufactured -Three-phase autotransformers 250 MVA 330/220 kV with voltage regulation at 220 kV side (BIL 1050) were manufactured -Single-phase transformer 62,5 MVA, 163 kV and three-phase transformer 63 MVA, 154 kV success-fully passed short-circuit withstand tests in KEMA testing laboratory (the Netherlands) -Manufacturing of control and monitoring systems was started -Single-phase transformer 500 MVA, 765/345 kV with voltage regulation at 345 kV side was manufac-tured -Shunt reactor 120 MVA, 800 kV was manufactured -Three-phase Magnetically Controlled Shunt Reactor 100 MVA, 220 kV was manufactured -Magnetically Controlled Shunt Reactor 180 MVA, 330 kV was manufactured and successfully com-missioned -Representative office was opened in Moscow (Russian Federation) -Representative office was opened in St. Petersburg, Krasnoyarsk, Yekaterinburg (Russian Federa-tion) and in Almaty (Kazakhstan) -Representative office was opened in Krasnodar (Russian Federation)

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MAGNETICALLY CONTROLLED SHUNT REACTORS

- NEW TYPE OF FACTS DEVICES

Flexible alternating current transmission systems (FACTS) devices are used for the dynamic control of voltage, impedance and phase angle of high voltage AC lines. FACTS de-vices provide strategic benefits for improved transmission system management and operation efficiency through better utilization of existing transmission assets; increased transmission system reliability and availability; increased grid stability as well as increased quality of sup-ply. The need for more efficient electricity systems management has given impulse to innova-tive technologies in power generation and transmission. Worldwide transmission systems are

undergoing continuous changes and restructuring. They are becoming more heavily loaded and are being operated in ways not initially forecasted. Transmission systems must be flexible to react to more diverse generation and load patterns. In addition, the economical utilization of transmission system assets is very important for utilities to remain competitive and to survive. Flexible AC Transmission Systems (FACTS) is a technology which meets these re-quirements. It significantly changes the way transmission systems are developed and controlled together with im-provements in asset utilization, system flexibility and system performance.

Magnetically controlled shunt reactor is a new type of FACTS devices which starting from 90th is widely used for voltage stabilization and reactive power control in transmission and distribution networks and at the level of in-dustrial consumers. Numerous advantages typical for magnetically controlled transformer equipment allow MCSR to keep leading position among other compensation devices. Main competitive advantages of MCSR are robust design similar to standard transformer design, high operational safety, optimal technical and economical characteristics, easy maintenance and significantly low price. Being equipped with series capacitors banks MCSR acquires full set of functional capabilities of known Static VAR Compensation (SVC) devices. Unlike standard de-sign of SVC composed with interconnection transformer, reac-tors, thyristor valve (100% of SVC rated capacity) MCSR is the only specific transformer device. Windings of this device act as SVC reactor while saturable core acts as back-to-back thyristor valve. As a result MCSR has only one power component instead of three power components of SVC. Field operation and mainte-nance of MCSR does not require complex protection and control loop, deionized water cooling, special education of maintenance staff and indoor installation. MCSR can be directly connected to the high voltage (HV) bus or line without using of interconnection transformer. This additional advantage makes possible to pro-vide full regulating range of MCSR at the voltage level where regulation is needed according to the network operation and dis-patch.

High level of Client-oriented quality characteristics of Magnetically Controlled Shunt Reactors were confirmed and en-sured during decennial field operation experience. In case even one MCSR is installed at predefined key substation continuous automatic control and optimal voltages support for several distri-bution substations on large region of electrical networks can be provided. Repair and maintenance expenses of transformer and switching equipment, which normally intensively participate in voltage regulation process, are decreased significantly. Considerable decreasing of equipment failure factor phe-nomenon (after commissioning of MCSR) is generally more evident in case of long HV network configuration and electric lines operated under conditions of reverse power flows.

FUNCTIONAL CAPABILITIES OF MCSR Magnetically Controlled Shunt Reactor is a three-phase static device operating on principle of continuous

regulation of inductive reactance. MCSR is designed for automatic voltage stabilization as well as compensation and regulation of reactive power flows. MCSR allows to:

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1. avoid daily and seasonal voltage oscillations in electric network due to rapid varying of consumed value of reactive power;

2. improve quality of electrical energy; 3. optimize and automatize conditions of power system operation; rapidly and efficiently respond on

changes of electrical parameters by remote control of MCSR set-point from SCADA/EMS terminal of relevant Dispatch Center;

4. significantly decrease losses of electric energy during power transmission and distribution; 5. significantly improve network stability; 6. improve maintenance conditions of electrical equipment by decreasing number of switchings of non-

regulated reactive power compensation devices and considerable decreasing number of taps changeover of unstable transformer’s LTC devices;

7. increase transfer capability of HV lines and provide secure automatic voltage control when active power flows are close to the thermal or stability limits;

8. avoid voltage collapses after network incidents (e.g., load rejections, generator and line outages, etc.);

9. provide favorable voltage conditions for operation of power generators.

MCSR FIELD OF APPLICATION Manufacturers and designers of MCSR defined the following electrical networks as the most favorable for its

application based on existing operational experience of MCSR and it’s functional benefits: - networks which sustain significant daily or/and seasonal fluctuations of electrical consumption; - networks with depreciated switching and transformer equipment, which is regularly used for voltage stabili-

zation; - networks which consist of long electrical transits being loaded with reverse power flows significantly varied

within short-term period; - networks distributing electric energy to consumers that are highly sensitive to voltage oscillations; - networks with excess losses of electric energy; - networks having voltage profile under which power generators can not operate within permissible reactive

power production range. Due to numerous MCSR functional and economical benefits it can be efficiently used in electric networks of

different voltage levels, independently from their ownership and level of dispatch hierarchy. Rapidly operating MCSR can continuously monitor consumed value of reactive power required to control dynamic voltage swings un-der various system conditions and thereby improve power system transmission and distribution performance.

PROSPECTIVE MCSR TYPES & REFERENCE LIST The most prospective types of MCSR are presented in the table below. This set of MCSR types was devel-

oped based on the requirements of our Clients and existing experience of JSC ZAPOROZHTRANSFORMATOR in the field of voltage stabilization and reactive power compensation. Specialists of dispatch centers and project de-partments from several countries provided numerous technical observations to be implemented in MCSR construc-tions. All their comments were considered during MCSR development. Other types of MCSR with different rated capacity and voltage level can be designed during 6-9 months including elaboration of design documentation

MCSR rated parameters

Type Rated capacity, kVA

Rated voltage, kV

Rated current, А

RTU-25000/110 25000 121 119

RTU -32000/110 32000 121 153

RTU -63000/110 63000 121 300

RTU -63000/220 63000 242 151

RTU -100000/220 100000 242 239

RTU -100000/330 100000 347 167

RTU -180000/330 180000 347 300

RTU -180000/500 180000 525 198

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The number of geographical regions and power companies using MCSR is continuously growing up. Annual Oder-In-Take of MCSR is doubled from year to year. Compared to 2001 when only few magnetically controlled reactors were installed in electric networks of Russian Federation nowadays 21 MCSR are already delivered to Client’s sub-stations in four countries, namely Russian Federation, Belarus, Lithuania and Kazakhstan. Total installed capacity of MCSR is 2028 MVAr. It is forecasted that this value will be doubled in 2008.

MCR Reference list

MCSR type Year of installation Place of installation Country TCR -180000/500 2005 Tavricheskaya s/s Russia TCR -180000/500 2005 Barabinskaya s/s Russia TCR -180000/500 2007 Agadyr s/s Kazakhstan TCR -180000/500 2007 Agadyr s/s Kazakhstan TCR -180000/500 2007 YuKGRES s/s Kazakhstan TCR -180000/330 2002 Baranovichi s/s Belarus TCR -180000/330 2006 Miradino s/s Belarus TCR -180000/330 2007 Ignalin NPP Lithuania TCR -180000/330 2008 Irtysh s/s Russia TCR -100000/220 2001 Chita s/s Russia TCR -100000/220 2005 Khabarovskaya s/s Russia TCR -100000/220 2006 Khekhtsir s/s Russia TCR -100000/220 2008 Vladivostok s/s Russia TCR -100000/220 2008 Nadym s/s Russia TCR -63000/110 2005 Sovetsk s/s Russia TCR -25000/110 1999 Kudymkar s/s Russia TCR -25000/110 2004 Igolskaya s/s Russia TCR -25000/110 2004 Dvurechenskaya s/s Russia TCR -25000/110 2004 Katylginskaya s/s Russia TCR -25000/110 2007 Sugmutskaya s/s Russia TCR -25000/110 2007 Fominskaya s/s Russia TCR -25000/110 2007 Fominskaya s/s Russia TCR -25000/110 2007 Aktogay s/s Kazakhstan TCR -25000/110 2007 Aktogay s/s Kazakhstan TCR -25000/110 2007 Novogodnyaya s/s Russia TCR -25000/110 2007 Vandmtor s/s Russia TCR -25000/110 2007 Churapcha s/s Russia TCR -25000/110 2008 Sochi s/s Russia TCR -25000/110 2008 Vostochnaya s/s Russia TCR -25000/110 2008 Bahilovskaya s/s Russia TCR -25000/110 2008 Urgal s/s Russia

PRINCIPLE OF OPERATION

Ihv Magnetically Controlled Shunt Reactor is almost usual transformer type technology. Functionality of semiconductor key device is achieved due to operation of MCSR cores in saturation range. This principle was the basis for the development of MCSR construction. Magnetic system of each phase of MCSR contains control winding and high-voltage winding. Both windings are placed on two solid semi-cores. When regulated DC voltage source is con-nected to control winding the DC magnetic bias flux appears in the core of MCSR. Alternative magnetic flux of HV-winding overlays with bias flux pro-duced by DC voltage source and thus resulting magnetic flux moves to the saturation range of MCSR core. Saturation of MCSR core causes appearance of inductive current in HV-winding. As magnitude of energy in control system changes, magnitude of inductive current in HV-winding changes correspond-ingly. Finally, it causes increasing or decreasing of reactive power consumed

IUHV

c

Uc

F1 F2

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by MCSR.

DC voltage source which produces current in control winding is fed by compensating winding of MCSR. Rectification of compensation winding alternative current is provided by small-power thyristor converter. Magni-tude of inductive current in HV-winding is regulated according to propor-tional principle. It means that tyristors operating angle is defined accord-ing to the difference between MCSR voltage set point and actual voltage of the bus MCSR connected to. MCSR superexcitation circuit is designed

to achieve quick change of MCSR loading from one quasi-steady state to another. In the mode of superexcitation MCSR changes its loading from no-load state to rated capacity during 0,15 seconds. Actually, there are no limita-tions on operating performance of MCSR. But optimal balance between MCSR performance and rated capacity of magnetic bias system was defined during practical experience of MCSR operation. Relevant performance analysis ensure that recommended time of MCSR loading / unloading is within interval 0,15-3 seconds. Depending on Cli-ent’s requirements MCSR can operate in the mode of voltage stabilization, consumption of reactive power fixed value or absorption of inductive current fixed value. Magnetically Controlled Shunt Reactors as well as non-regulated reactors can be two types: bus MCSR and linear MCSR. Depending on type or upon request of the Client construction of MCSR is completed with additional element which provide preliminary biasing of magnetic system and subsequent instantaneous loading up to nominal capacity directly after switching to network. As any trans-former device MCSR allows continuous overloading up to 110-130% of rated current and due to specific design can be also shortly overloaded up to 200%. MCSR can, if necessary, operate as usual non-regulated reactor hav-ing all its functional capabilities including arc quenching during autoreclosing.

iω Fs - Fs

MCSR electric circuit diagram is presented below. Electromagnetic system is the main power element of Magnetically Controlled Shunt Reactor. Electromag-

netic system consists of HV winding which is connected directly to the electric network, compensation winding and control winding. In some MCSR design decisions compensation and control windings are constructed as a single winding. HV winding is used for consumption of reactive power from network while control winding is responsible for magnetic biasing of MCR core. Compensation winding is implemented to feed DC voltage source and to loop harmonics aliquot to three inside the winding.

Oil transformer with Converter (OTC) is designed for regulation of DC current magnitude in control winding of electromagnetic system via changing magnitude of DC voltage on the terminals of Converter (DC voltage source). Rated capacity of OTC is usually equal to 1-2% of MCSR rated capacity. Some designs of MCSR are equipped with 2 or 3 OTC connected in parallel. This is allow to increase redundancy of MCSR construction and ensure its stable operation even in case of failure of the main OTC. Normally all OTCs (except OTC which is used for prelimi-nary magnetic biasing) are connected to the compensation winding.

Automatic control system (ACS) of MCSR generates control signals to the thyristor valves of Converter (DC voltage source). According to these control signals Converter changes the magnitude of DC voltage in magnetic biasing system and MCSR loading with reactive power changes correspondingly. ACS is an electronic device allo-cated in standard cabinet. Input power of control system is less than 1kW.

MCSR Electric Circuit Diagram

А В С N

Circuit Breaker

CW

CW

TCRB

HV busses VT

CB

OTC

OVL

Rel. Pr.

ACS

OVL

VT

LV busses

CT 7

CT 5

CT 6

CT 8

HVW

CT 1

CT 2

CT 4

CT 3

UAB UBC UCA

U ia ib ic

= 220 V

CT 1 - CT 6

ТМПх30 БУЗ1х12 БУЗ2х12

Auxiliary CB

Standby OTC

CtrW

- TCRB – Thre- HVW - High - CtrW - Contr- CW - Comp- OTC - Oil Tr- ACS - Autom

ТТ 2 ТТ5-ТТ8 фаз А

- CT 2 - CT5-ТТ8- А, В.С

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UAB UBC А, В, С; ОН х 3

e-phase Controlled Reactor with Blower cooling (electromagnetic system) Voltage Winding; ol Winding; ensation Winding; ansformer and Converter; atic Control System.

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MCSR OPERATION EXPERIENCE ON SUBSTATIONS OF INDUSTRIAL CONSUMERS

Beginning 2004 three RTU -25000/110 were installed at the 110 kV substations Dvurechenskaya, Katylginskaya and Igolskaya. By the end of 2003 it was a critical situation at Uzhny Vasugan oilfields of Tomskneft’ JSC. During several years continuous load buildup was observed due to expansion of industry. Total length of distribution network 110 kV which supplies power to consumers of the region exceeds 700 km. Electric energy from generation sources trans-mitted to the deficit region through backbone 220 kV network. This network was designed and constructed as two closed transits which respect N-1 criteria concerning security of power supply in case of failures. However due to

the big difference of voltage angels at the end of each transit they were forced to operate in open mode. Under such condi-tions voltages in 110 kV network were significantly reduced up to 85% of its rated value (90 kV). As a result transmission capacity of electric lines was absolutely exhausted. Major consumers of the region are synchronous and asynchronous machines (90% of total consumption) which are very unstable to the voltage oscillations caused by power system distur-bances (short circuits, electric lines tripping, connecting and disconnecting of load, etc.). One network incident usually caused full disconnection of all synchronous and asynchro-nous machines and voltage jumps up to 128-130 kV. Tomskneft’ JSC suffered great looses in oil production re-sulted both from undersupply of energy and often disconnec-tion of electric engines during voltage deviations and unse-cured operation of distribution network. By the end of 2004 number of emergency outages of oil consumers reached 392 per year (60 times at some months). Oil underproduction in-

creased to 38,500 ton per year (more than 7,500 ton at some months). Secure level of energy supply was not achieved even after three series capacitors banks (total rated capacity 3 x 54 MVAr) and gas-turbine unit (rated capacity 24 MVAr) were installed in 110 kV network. Maintenance staff continuously changed tap positions of transformers and switched series capacitors banks due to sig-nificant voltage oscillations, thunderstorm activities and com-plex programs for connection / disconnection of equipment. Commutations of series capacitors resulted in 10-15 kV volt-age jumps which were still inadmissible for stable operation of consumers. Cascading disconnections of synchronous and asynchronous machines took place regularly. Operation condi-tions were significantly changed only after three 25 MVAR Magnetically Controlled Shunt Reactors were commissioned at Igolskaya, Dvurechenskaya and Katylginskaya substations in August-October 2004. Transfer capacity of 110 kV lines was increased on 30-50%, voltages were stabilized on 105-110% of its rated value and could be adjusted in a wide range de-pending on operation conditions. Next benefits were noticed by the Client even after short period of MCSRs operation: 1. MCSRs equipped with series capacitors banks provide op-timal flows of reactive power and maximize transfer capacity of electric lines up to the thermal limits.

2. Enhancement of distribution network to voltage level 220 kV was postponed. 3. Losses of electric energy in the regional network were decreased more than on 35% (from 11,9 MW to 7,5 MW). 4. Smooth automatic stabilization of pre-set voltages was provided for steady states, number of series capacitors banks switching off was significantly reduced, usage of transformer’s LTC for voltage regulation was almost avoided. Cascading load tripping was completely eliminated. Emer-gency disconnection of individual synchronous or asyn-chronous engines did not lead to voltage jumps and has no influence on the rest engines. Number of special measures for electric lines and other electric equipment connection /

disconnection was reduced. It allows to provide maintenance and repair works without danger of consumers’ power

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supply interruption. Losses in oil production were reduced more than 50 times. Pay-back period of installed MCSRs was equal to 1 month.

OPERATION OF MCSR IN DISTRIBUTION NETWORKS

Efficiency of MCSRs operation in 220-110 kV net-works can be analysed on the examples of substations Kudymkar and Chita, Russia.

Kudymkar substation is fed from subsystem Per-menergo by two 110 kV lines with length more than 100 km. Regular voltage oscillations within the range 97-120 kV were caused by significant seasonal and daily changes of loads as well as by remote position from generation sources. Existed series capacitors bank were switched several times per day (total number of commutations reached 800 times per year). Continuous voltage regula-tion by means of transformers LTC was also used. 1800 tap change procedures were registered within 1 year. Dur-ere equal to 10-15 kV. Having big voltage deviations, worn

circuit breakers of series capacitors and worn LTC of transformers power system additionally suffered from excess losses of electric energy which were caused by non-optimal flows of reactive power.

During technical and economical

ing switching of series capacitors bank voltage jumps w

analysis it was defined to solve existed voltage problems by installation of Magn

MCSR

s at the bus MCSR connected to are limited within 1,5% of MCSR voltage set point; uced

in 10ses of energy were reduced on 2,5 MW. Under these conditions

pay-ontrolled Shunt Reactor does not need involvement of maintenance

staff. MCSR ensured no-break power supply of consumers of Komi-Permyatskiy region and allowed to postpone

consce 1999) neither failures of reactor itself nor relay protection

miso

TU-100000/220 was installed at substa

etically Controlled Shunt Reactor at Kudymkar substation. Operating together with already installed series capacitors banks MCSR should have same functional capabilities as standard Static VAR Compensator (SVC). These analyses were completely approved during practical operation. Furthermore, price of MCSR equipped with series capacitors bank is twice cheaper than price of analogous SVC devices. Commissioning and maintenance expenses appeared to be lower as well because commissioning and maintenance procedures of MCSR are the same as corresponding procedures for standard non-controlled shunt reactors and transformers. MCSR is de-signed for outdoor installation and does not require special operational staff knowledge and skills for maintenance.

9 months after commissioning of MCSR at Kudymkar substation analysis and registered parameters of operation were presented for power industry specialists during the seminar. Members of the seminar stated

the following decisions: 1. voltage oscillation2. number of series capacitor banks switching and changing tap positions of transformer’s LTC was red0 times (approximately 1 operation per year); 3. during maximum loads demand periods losback period of MCSR is equal to 3 years; 4. in the automatic mode Magnetically C; 5truction of new 220 kV line for 10-15 years. 6. during whole period of MCSR operation (sinperation took place.

Rtion Chita and connected to 220 kV

bus-bar in 2001. Nearby in power system Chitaenergo have been already in opera-tion other voltage regulating devices – two non-controlled shunt reactors with rated capacity 100 MVAr. One of them installed at Haranorskaya TPP was switched off at least 2 times per day during summer pe-riod. New MCSR according to its operation principle allows to change its capacity within whole regulating range unlimited number of times. Continuous voltage regu-lation by means of MCSR made possible to desist from switching of non-controlled reactors. Voltage profile in the network was corrected and voltage oscillations were eliminated. Number of annual main-

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tenance works on circuit breakers was reduced. Installation of MCSR made possible commissioning of new OHL 220 kV. Its connection to the network as well as field tests execution (no-load operation, autoreclosing tests, etc.) were not possible without equipment providing smooth regulation of reactive power.

Regional Dispatch control center of Chitaenergo power system provided summary of the results and benefits of MC

agnetically Controlled Shunt Reactor allows continuously compensate reactive power gener-ated b

tly increased.

erate in the mode of reactive power consump-tion.

4. Tripping of low loaded 220 kV lines were no more applied for reducing voltages in the network.

MCSR AS A SOLUTION FOR FULL-SCALE VOLTAGE STABILIZATION IN TRANSMISSION NETWORKS

ince 1991 power system of Belarus experienced strong decreasing of active power load demand. Exces-sive a

existed voltage problems in the

voltage 330 kV. As it was summarized during economical analysis

CSR OPERATION ON LONG DISTANCE HIGH VOLTAGE TRANSITS

msk power system includes long 500 kV transit connecting Russian power system with power system of Kazak

SR operation: Application of My high voltage lines. Next benefits were additionally achieved due to MCSR operation: 1. Necessary conditions were provided for commissioning of new 220 kV OHL. 2. Quality of electric energy in Chita and Buryatiya power systems was significan3. Existed voltage oscillations in the network were stabilized. 3. Units of TETS-1 power station were not more forced to op

5. Safety and stability of power supply were increased.

Smounts of reactive power which previously served to ensure long distance active power transfer appeared in

750-330 kV transmission network. Free surpluses of reactive power caused significant voltage buildup at each voltage level of power system. Regulating range of all reactive power compensating devices was exhausted. Set of uneconomical and unsafe measures were taken daily to prevent violation of voltage limits during minimum load periods. The most popular among them were: tripping some 330 kV lines to de-crease charging capacity of the network, large scale disconnection of consumer’s se-ries capacitors banks, operation of synchro-nous generators in the mode of consumption of reactive power, regular transformer’s LTC taps changing. Realization of these meas-ures always increased losses of electric en-ergy significantly and violate security con-strains for safe power transmission and sup-ply.

Solution for power system of Belarus must have

been found for all voltage levels and consid-ering all recent changes of operation condi-tions both in transmission and distribution networks. The number of research analysis and investigations were carried out to define measures necessary for normalization of voltage profile. Finally, it was decided and economically approved to install four shunt reactors (1 non-controlled shunt reactor and 3 MCSRs) rated capacity 180 MVAr and ratedexisted losses of electric energy in the power system were so big that after installation of MCSRs and stabilization of voltages at optimal level the pay-back period of MCSRs will be less than five years.

M Ohstan. Synchronous operation of these systems depends on safe operation of interconnected 500 kV lines.

During separate operation of Russian and Kazakh systems existed non-controlled shunt reactor at substation Tavricheskaya was switched off more than 40 times per day according to changes of active power flows and volt-age profile in the network. After resynchronization of Kazakh and Russian systems in July 2000 safety of power supply was increased but voltage oscillations increased as well. Before commissioning of RTU-180000/500 high voltages and excess losses of electric energy were continuously observed in Omsk subsystem. Voltage oscillations

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were directly depended on magnitude of active power flow on 500 kV transit. Any time magnitude of active power flow decreased voltages at 500 kV network reached boundary values or even violated upper voltage constraints. In December 2005 MCSR 180 MVAr 500 kV was installed in Omsk subsystem at Tavricheskaya substation.

MCSR allowed to solve next proble

2. e overload

3. g off non-

App MCSR allowed to suppo

ms existed in Omsk subsystem: 1. early deterioration of elec-

tric equipment; switching voltagof equipment; often switchincontrolled compensation devices. lication of

rt voltages in the nearby net-work at constant safe and optimal level independently from magnitude of active power flow and loading demand profile. MCSR almost instantaneously respond on short circuit and have all functional capabilities of non-regulated shunt reactor including arcquenching during autoreclosing. For some opera-tional conditions MCSR keep voltages amum transfer capacity of 500 kV transmission line.

t substation bus-bars equal to the high permissible value ensuring maxi-

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JSC “ZAPOROZHTRANSFORMATOR” REPRESENTATIVE OFFICES

OSCKOW

REPRESENTATIVE OFFICE IN ST.PETERSBURG

ederation

m.ru

REPRESENTATIVE OFFICE IN EKATERINBURG

ederation

it.c m ENTATIVE OFFICE IN KRASNOYARSK

ation

f Kazakhstan REPRESENTATIVE OFFICE IN KRASNODAR

ration

u

3, Dnepropetrovskoe shosse, Zaporozhye IN THE RUSSIAN FEDERATION69600, Ukraine REPRESENTATIVE OFFICE IN MTel. +380 61 2703900 build. 1, 17/2 Bolshaya Yakimanka str. Fax +380 61 2703232 119180, Moskow, Russian Federation e-mail: office@ztr.ua Tel.: +7 (495) 7458828, 7458840 http://www.ztr.ua Fax +7 (495) 2382415 ztr-secr@esgr.ru Sales Department Tel. +380 61 2703033Fax +380 61 2703939 Office 409, 5 Krapivniy side str. e-mail: sales@ztr.ua 194044, St. Petersburg, Russian F Tel.: +7 (812) 3364445 FOR SUPPLIES OUTSIDE CIS COUN- Fax +7 (812) 5426571 TRIES ZTR_SPb@mail.quantuZTR-ENESTA Handelsgesellschaft m.b.H. Joint Venture between ZTR and VAIT Strasserau 6, A-4010, Linz Offise 410, 22 Karl Libkneht str. AUSTRIA 620075, Ekaterinburg, Russian FTel. +43 732 7804247 Tel./Fax: +7 (343) 3792137 Fax +43 732 7804399 edozorov@mail.ru e-mail: ztr-enesta@va o http://www.ztr-enesta.com REPRES Office 309, 110 Dubrovinskogo str. REPRESENTATIVE OFFICE 660021, Krasnoyarsk, Russian FederIN THE REPUBLIC OF KAZAKHSTAN Tel.: +7 (3912) 212327 AND MIDDLE ASIA Fax +7 (3912) 680442 Office 701, 151/115, Abaya Avenue, wladimir-khv@mail.ru Business centre “Alatau”, 050009, Almaty, Republic oTel.: +7 (3272) 3334692 Office 409,135/1 Turgeneva str. Fax +7 (3272) 3334696 350000, Krasnodar, Russian Fedeoffice@ztr.kz Tel.: +7 (861) 2201965 Fax +7 (861) 2201928 info-ztr-krasnodar@yandex.r

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