Experimental Study on the Influence of Different Opening Speed on Post-Arc Current in DCCB

The pre-charged capacitor method, used in the active current injection circuit breaker in DC system, is an effective approach to realize the current injection. However, in practical applications, the performances of post-arc among different opening speed are still unknown, which have been an obstacle that blocks the design of MV DCCB. To solve this problem, high resolution measuring equipment was used to investigate the performances of vacuum circuit breaker in post-arc period. The experimental results show that the peak value of the post-arc current can be up to 6A and the post-arc current decays to zero within 10μs after current-zero. Besides, with the increase of opening speed, the fluctuation of post-arc charge increases continuously, while the average remains basically unchanged.

I. Introduction

The great advantages in efficiency, flexibility and stability have made DC grids show more and more potential in the future transmissions and distributions network [1]. Compared with AC system, DC system is more adaptable in terms of integrating the renewable energy and improving the transmission capability. However, as one of the most important equipment to protect the system when fault occurs, the development of MV DCCB is still a challenge. It still needs a lot of works to perfect its research [2].