Investigation on Dielectric Recovery Characteristics of CO2 Gas Circuit Breakers With Current Commutation Regulation

Abstract

This article proposed a current commutation regulation (CCR) connected in parallel with a CO2 gas circuit breaker (GCB) in order to improve the dielectric recovery characteristics (DRC). The structure and principle of the CO2 GCB with CCR are proposed and analyzed. The CCR is composed of serial-connected thyristors and a current-limiting resistor. The current of the CO2 GCB will decrease to zero before the main current zero so that there is a zero-current duration between the current zero of the CO2 GCB and the main current zero, which supplies more recovery time for DRC of CO2 GCB. The DRC test platform of the CO2 GCB with or without CCR is set up. The current commutation characteristic is analyzed and tested. The effect of the CCR on the zero-current duration and the DRC of the CO2 GCB is gained by adjusting the applied time of the negative pulsed voltage. The results show that the CCR can create a zero-current duration of 0~1.5 ms, and the DRC of the CO2 GCB can be increased to twice when the zero-current duration is 0.8 ms. The current commutation characteristics and effects of CCR are verified. This article provides a new method to improve the DRC of the CO2 GCB, which is useful for the application of SF6 alternative gas.