Experimental Research on DC Interruption Characteristics of Vacuum Interrupter by Forced Current Zero

In the DC grid, fault current rises very fast due to low impedance. Fast DC circuit breakers are needed to isolate faults and avoid a collapse of the common DC grid voltage. Based on the forced current zero technology, the vacuum interrupter (VI) equipped with fast electromagnetic repulsion mechanism is a very promising solution of fast DC interruption. This paper presents experimental research work on DC interruption characteristics of a vacuum interrupter. The post-arc current and transient interruption voltage (TIV) are measured with a current zero (CZ) diagnostic system. The influence of the breaking current, di/dt, rise of rate of initial TIV (RRITIV) after CZ and electrode separation on the post current have been analyzed.