SVCs enable increased use of low-cost power generation

Since 1986, Kansas Gas and Electric Co. (KG&E) of Wichita has operated two static var compensators (SVC), delivered by ABB, at the Murray Gill and Gordon Evans 138 kV substations in the Wichitha area.

The compensators, having a combined dynamic rating of 500 Mvar, were delivered on a turn-key basis.

Power is being transmitted to the Wichita region over a dis-tance of 100 miles from the Wolf Creek nuclear power station by means of two 345 kV lines. The purpose of the compen-sators is to stabilize the voltage of the 138 kV system around Wichita during various network conditions, including major disturbances such as loss of either of the 345 kV feeding lines.

As a major benefit, local fossil-fuelled generators could be shut down, with considerable savings in production costs with the compensators in operation. According to studies perfor-med by KG&E, the fuel cost saving alone would pay for both SVCs within two years time.

Before investing in SVC, KG&E evaluated as an alternative to build additional EHV lines. The SVC solution was decided upon for the following reasons:

− The two SVCs cost only a fraction of one more EHV line − With SVC, R/W costs and acquistion problems were avoided − Shorter construction time of SVC compared to EHV line − SVC less exposed to damage than EHV lines − Greater maintenance flexibility with SVC

Technical data

Murray Gill Gordon EvansControlled voltage 138 kV 138 KVDynamic rating 25 Mvar inductive to 0 to 300 Mvar 200 Mvar capacitive capacitiveControl system 3-phase voltage control by means of a voltage regulatorThyristor valves Water-cooled 3-phase valves with magnetic triggering

75 Mvar 75 Mvar 75 Mvar

50 Mvar

200 MVA

138 kV

75 Mvar 75 Mvar 75 Mvar 75 Mvar

75 Mvar

300 MVA

138 kV

Murray Gill Gordon Evans

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For more information please contact:

ABB ABFACTSSE-721 64 Västerås, SWEDENPhone: +46 (0)21 32 50 00Fax: +46 (0)21 32 48 10

www.abb.com/FACTS

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SVC performance during contingencyThe figure shows the voltage-supporting effect of the SVC during a severe fault situation at distribution level causing voltage drop in the feeding network. As can be seen from the Compensator response, the SVC has responded fully to the fault within less than 2 cycles, thereby increasing the 138 kV voltage and evading undervoltage tripping of the lines.

1 Main bus2 TCR group3 TSC group4 Filter group5 Thyristor valves6 Cooling system7 Control room8 Auxiliary transformer