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

This article proposed a current commutation regulation (CCR) connected in parallel with a CO
₂
gas circuit breaker (GCB) in order to improve the dielectric recovery characteristics (DRC). The structure and principle of the CO
₂
GCB with CCR are proposed and analyzed. The CCR is composed of serial-connected thyristors and a current-limiting resistor. The current of the CO
₂
GCB will decrease to zero before the main current zero so that there is a zero-current duration between the current zero of the CO
₂
GCB and the main current zero, which supplies more recovery time for DRC of CO
₂
GCB. The DRC test platform of the CO
₂
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 CO
₂
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 CO
₂
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 CO
₂
GCB, which is useful for the application of SF6 alternative gas.