417 / 2017-04-27 13:48:31

DC current interrupting characteristics of CO2 and SF6 based on self-excited oscillation under transverse magnetic field

13548,13686,13685,13863

Self-excited oscillation-type DC circuit breakers (DCCBs) has various merits, such as low operational losses, low cost, high voltage level ( 100 kV) suitability and high reliability. Numerous researchers investigated the interrupting capabilities of the self-excited oscillation-type DCCB. However, there is lack of investigation of DC self-excited oscillation interruption under transverse magnetic field (TMF). The objective of this paper is to investigate the effects of transverse magnetic field on DC interruption of CO2 and SF6 gases based on the self-excited oscillation principle. A dead tank-type gas circuit breaker was used as a test circuit breaker. The DC self-excited oscillation interrupting characteristics of CO2 and SF6 at 0.5 Mpa absolute atmospheric pressure were investigated by applying TMF of 0 mT, 200 mT with a puffer-type structure as a benchmark through experiments. The arc behaviours were also observed by a high speed digital camera. The arc parameters and parameters of the commutation circuit gotten from these experiments were used in the simulations of the interruption process. The interrupting characteristics and the arc behaviours of CO2 and SF6 were compared. The experimental results show that applying TMF of 200 mT can significantly reduce the arcing time compared with TMF of 0 mT and puffer-type structure. The DC interruption capacity for the SF6 insulation is higher than that for the CO2 insulation under the same experimental condition. The simulation results and experimental results of arcing time are fit well. Thus applying TMF of 200 mT is an effective method to improve the self-excited oscillation DC interruption capacity of DC circuit breakers.