Study of capacitive current breaking capacity with extremely high recovery voltage

There are AC filters in the HVDC substation; it is possible that extremely high recovery voltage occurs when the AC filters are switched with circuit-breaker. So some special requirement is put forward to circuit-breaker, which is the circuit-breaker must break small capacitive current with very low probability of restrike and very high recovery voltage. In this paper, we analyze the electric intensity and gas density of the key position during the process of recovery voltage rising by means of the finite element analysis software, and judge the capacitive current breaking capacity of the circuit-breaker that will be used to switch 800kV AC filters. Basing on the result of analysis, we adjust the velocity of opening, the shape of contactor or number of break series in one pole etc which is the influential factor of breaking capacity and repeat the analysis until the result meet the requirement of capacitive current breaking in theory.