Distribution Network Parallel Compensation Capacitors Operating Voltage Research

Shunt capacitor banks are now widely applied for reactive compensation in power system as a reactive source. With the rapid increase of power network capacity and the continual demand for better power quality, the switching of capacitors is becoming more and more frequent, in addition, the wide use of vacuum circuit breakers brings some new characteristics of operation overvoltage of shunt capacitors, which menaces insulation of facilities, becoming an important factor for reliable operation of power network. Therefore, it is necessary to make a thorough research on the operation overvoltage of shunt capacitors and its protection measures.This paper takes two typical substation of Hangzhou power supply company as simulation models, first analyzes the characters of several possible overvoltages and their influence factors, then focuses on the method of employing metal oxide surge arrester to control the operation overvoltage, including compare analyses of different connection types of surge arrester, parameter design and application type selection for different surge arresters, at last, presents the application condition for several best connection types of surge arrester.At present, the method of using arrestors to protect shunt capacitors is not detailed described in the Criterion, especially the parameter design and application type selection for different arresters haven't been regulated yet, which causes the protection measures applied haven't well exerted their effect. This work can help select the best protection measure based on different power network situation, and I hope it will be applied in real power system.