Measurements and modelling in the current zero region of vacuum circuit breakers for high current interruption

Post arc current and voltage measurements with high time resolution were carried out with industrial vacuum circuit breakers for investigating their current zero conditions and current interruption. Based on experimental results, plasma parameters were estimated by means of a modified “continuous transition model”. Dielectric effects in the post arc current zero region were detected and modelled. At lower current amplitudes (Iˆ<16 kA), typical post arc currents were obtained. At higher current amplitudes, the probability of higher post arc current charges increases without the occurrence of breakdowns. It has been shown that charge generation takes place in the post arc current region