Study on the Selecting Closing Resistance Method of 1000 kV ac Filter Break Circuit Breaker

In UHVDC systems, AC filter circuit breakers need to be switched frequently to meet system operation mode and system load changes. When the AC filter circuit breaker switches the filter bank, it will produce severe closing inrush current and closing overvoltage, resulting in electrical shock and degradation of circuit breaker performance. In order to specifically analyze the closing characteristics of 1000kV AC filter circuit breaker, the paper first builds a simulation model of four-break circuit breaker, introducing the principle of closing resistance input, analyzing the inrush current and closing overvoltage waveforms of different types of filters. Then analyzes the influence of using different closing resistors on closing inrush current for HP(Hodrick-Prescott) type filters. The results show that when the closing resistance exits, a large closing inrush current will occur. Reducing the closing resistance value can effectively reduce the size of the closing inrush current. Considering the closing inrush current and closing overvoltage, using conventional closing operation, the closing resistance of HP24/36 filter circuit breaker is optional 600 ohm.