Optimization of Current Breaker and Fault Current Limiter in DC Micro-grid based on Faulty Transient Analysis

It is an effective fault protection strategy in DC micro-grid (DCMG) to use a fault current limiter (FCL) to limit short-circuit current and circuit breaker (CB) to break faulty line. The complex topology of looped-type DCMG increases the difficulty of CB and FCL optimization placement in looped-type DCMG. This paper simplifies the faulty looped-type DCMG model and analyzes expressions of CB currents after faults occur. Then, this paper constructs a CB and FCL optimization placement model. CB breaking capability and FCL inductance are used as optimization goals, while short-circuit breaking capacity of CB is used as constraint condition in the model. Finally, this paper uses an improved NSGA-II to solve the optimal placement of CB and FCL in a five terminal DCMG model.