Comparison of Short and Long Term Use of Synchronous Control versus Closing Resistor Switching Methods for Capacitor Switching

摘要

Reactive power compensation is critical for effective operation of renewable and distributedgeneration sources. Switching capacitor banks is a key part of the solution and is a difficult duty forthe switching device, requiring special consideration to minimize voltage and current transients. Twowidely accepted switching methods are synchronous control (Point on Wave Control) and closingresistors to mitigate transients. This paper will compare the system and equipment impact fromswitching capacitors with each method. The influences on their ability to mitigate transients will bepresented and discussed. While both methods are effective, the long term operational ability andperformance repeatability is quite different between the two methods. Maintenance and tuningrequirements must also be considered.For a given set of realistic hypothesis, a systematic comparison of transients from 145 to 420 kV hasbeen performed between use of a synchronizing relay with inrush reactor and closing resistors withoutinrush reactor. Influence of circuit breaker aging has been studied as well as influence of frequency(50/60 Hz). A specific focus on the electrical wear generated at the closing of back to back banks isdone.