The peculiarities of Transient Recovery Voltage in presence of Post Arc Current in Vacuum Circuit Breakers

Abstract

The post arc phase is a critical part in the current interruption process of Vacuum Circuit Breakers (VCB). During this step, the dielectric strength of VCB has to be recovered. In order to improve the performance of VCB, investigation of Post Arc Current (PAC) in the presence of Transient Recovery Voltage (TRV) is presented in this paper. The equations of ion sheath length and PAC are solved together with network equations, which describe the TRV and PAC interrelation. In order to solve nonlinear ion sheath equations simultaneously with PAC and TRV equations, a Gauss-Seidel method is applied. The simulation results for PAC and TRV properly are in an acceptable accordance with the previous studies and available experimental records. The simulation results indicate that in the case of Short Circuit (SC) current interruption, there is no considerable influence between PAC and TRV. In the case of capacitive current interruption, TRV waveform in the first microseconds is highly influenced by the PAC. The results specifically demonstrate that the impact of physical parameters of VCB like diffusion time constant and initial PAC is much more significant than that of circuit parameters like capacitance of capacitor bank and equivalent network inductance.