A Novel Topology of Hybrid DC Circuit Breaker with High Current Breaking Capacity

With the large-scale integration of renewable energy sources into the power grid, power disturbances and impacts in the power system have increased significantly. Hydropower units are required to suppress such fluctuations through frequent regulation. To ensure the safe operation of hydro-generators, the circuit breakers in the excitation circuit must break the fault current when a short-circuit fault occurs. Hybrid DC circuit breaker (HDCCB) is a new type of circuit breaker that combines mechanical circuit breakers (MCBs) and power electronic (PE) switches. It can break the current rapidly with high reliability. However, it suffers from excessive losses in the excitation circuit. This paper proposes a novel HDCCB topology that utilizes SiC MOSFETs to reduce losses and analyzes its operation principle. To enhance the current breaking capacity of the HDCCB, this paper proposes a method of elevating the gate drive voltage. Finally, the proposed topology and control method are verified through simulations.