Short circuit current fast blocking strategy based on solid state limiter

Micro system protection is to ensure network security and stable operation, the basis of one aspect can be cut off the micro network fault through the inside and outside, on the other hand and control, communication and other units to reduce failure on the network and the impact of the stable operation of the distribution network. In the short circuit protection of communication micro-network, the traditional mechanical circuit breaker has the power of switching arc phenomenon, which limits the fault current, but brings greater security risks. The solid-state circuit breaker USES the power semiconductor to make the main switch tube, which can realize the short-circuit current fast without arc breaking, while avoiding the interference of the fault current to the grid bus voltage. A solid-state short-circuit current interrupter (LCSRSCB) based on LC series resonance circuit is proposed. In normal mode, due to the configuration of resonant structure (capacitor and reactor), the influence of the original circuit is negligible. Failure mode, by controlling the on and off the main switch tube, the topology of the LCSRSCB change for LC oscillation rectifier bridge, power grid voltage of capacitor recharge quickly, using the reverse blocking capacitor voltage short-circuit current. In order to improve the speed of the interrupter, differential protection is used to detect short-circuit status. The capacity of LC resonant structure and switching tube was selected for two operation modes, and the running loss of LCSRSCB was analyzed. Simulation and experiment are carried out to verify the effectiveness of the proposed method. Compared with the traditional blocking circuit, this circuit is simple in structure, quick in response and strong in flow. It is very suitable for ac micro grid applications.