The operation status of AC filter

circuit breaker and control & protection device

as the main equipment of converter station

have direct effect on the safe operation of DC system. For improving reliability of AC filter and circuit breaker

in this paper

the cause of fault for the AC filter and circuit breaker at certain converter station is analyzed. The quality defects in the inner insulation tube and the closing resistor of the circuit breaker is judged by such methods as analysis of gas composition

fault waveform

conventional test data and disassembling inspection. The flashover discharge fault is generated due to continuous reduction of insulation level across open contacts with frequent switching of AC filter during the operation. Many groups of BP11/13 AC filter are tripped due to overvoltage of the fault of the circuit breaker because of the design in the support insulator of BP11/13 AC filter capacitor tower;causing the absolute minimum filter cannot meet requirement and leading to DC power reduction. Finally

the corresponding treatment measures for the cause of the fault so to eliminate the hidden danger of the DC system in theoperation.