Investigation of an Active Current Injection DC Circuit Breaker Based on a Magnetic Induction Current Commutation Module

Active current injection circuit breakers (ACICBs), which utilize the mechanical switch and a parallel-connected precharged capacitor, have broad application prospects in future multiterminal dc grids. However, with the increase of system voltage, the precharged capacitor leads to the great cost and size being spent on the charging circuit and auxiliary commutating appliances. To address this shortcoming, an innovative dc circuit breaker (DCCB) based on a magnetic induction current commutation module (MICCM) is proposed. The influence of the main component parameters on the commutation performance is investigated by calculation, in which the self-, mutual, and stray inductances are involved. Besides, the validity of calculation is experimentally proved. Then, by applying the MICCM to the ACICB, the breaking characteristics of the ACICB are analyzed in detail. Finally, a 10-kV DCCB prototype is developed, verifying the feasibility of current commutation concept and the validity of simulated interruption results. Our studies show that a 10-kA bidirectional fault current can be interrupted successfully with a commutation duration less than 250 μs.