Study on Post-Arc Current of DC Current Interruption Using Vacuum Interrupter

The Post-arc current (PAC) behavior of DC current interruption was investigated using a mechanical DC circuit breaker (DCCB) with 72 kV vacuum interrupter (VI) applied to the main interrupter. The mechanical DCCBs are required to interrupt high frequency current with large current slope (di/dt) at current zero. It shows a considerably large amplitude of PAC which exceeding 100 A after DC current interruption. The PAC model commonly used for PAC investigation of AC current interruption was found to be applicable to reproduce the PAC in DC current interruption. As a results of the PAC model simulation, the parameters affecting the amplitude of the PAC are di/dt at current zero and rate of rise of the initial transient interruption voltage (dv/dt) during the PAC period and the impact of the amplitude of the interruption current was small.