Minimizing Overvoltages on Medium Voltage VCBs Due to Shunt Reactor Switching

Overvoltages related to shunt reactor switching is one of the most important phenomena that has challenged the operation of medium voltage circuit breakers. In the present article, the overvoltages caused by switching of shunt reactor by a 20kV vacuum circuit breaker (VCB) are investigated and some efficient solutions to control them are presented. This study was performed on a real power network and the results were presented for various considerations. Surge arresters and RC snubbers are the most common and efficient tools for controlling switching overvoltages. The use of these types of equipment in different conditions has been studied and compared with each other. This comparison has been performed in two cases with and without the phenomenon of multiple reignitions. For a more practical study, compliance with the requirements and related common standards is also included in this study. Also, the effect of the switching instant on the level of overvoltages and the phenomenon of multiple re-ignition has been investigated. Finally, according to the conclusions of various studies, a practical and appropriate solution for controlling overvoltages is introduced.