±535kV High Voltage DC Circuit Breaker Insulation Test Analysis

This paper introduces insulation tests of a ±535kV mechanical high voltage DC circuit breaker, which is used for Zhangbei flexile DC transmission project. First, the load characteristics of each branch were analyzed, including main branch, transfer branch, energy dissipation branch and buffer branch, and the specific test items were proposed. Then, the test circuit and arrangement of lightning impulse withstand voltage were analyzed, switching overvoltage and test waveform of DCCB were also discussed. At last, long-term DC partial discharge measurement and characteristics were analyzed. This article also discussed some problems and solutions encountered in specific tests.