Fast protection strategy for monopole grounding fault of low-voltage DC microgrid

Abstract

• This paper presents a low-voltage DC microgrid ground short-circuit fault protection system based on positive channel metal oxide semiconductor (PMOS). • In case of ground short-circuit fault in DC microgrid, the coupling energy of the short-circuit current makes the PMOS to be turned off reliably. • In addition, because the primary inductance of the transformer plays a certain current limiting role, the turn-off current of PMOS will not increase sharply. Low voltage DC microgrid has attracted more and more attention in smart grid with its advantages such as low network loss, large transmission capacity and easy direct access to distributed power supply. However, compared with the traditional AC microgrid, the DC microgrid lacks inertia support and the fault develops rapidly, which makes the existing short-circuit current protection technology difficult to meet the requirements of accurate and efficient troubleshooting. Therefore, this paper presents a low-voltage DC microgrid ground short-circuit fault protection system based on positive channel metal oxide semiconductor (PMOS) self-powering DC solid-state circuit breaker protection elements, and verifies the feasibility and effectiveness of the protection system through simulation experiments. The experimental results show that the proposed protection system based on solid state circuit breaker will not affect the voltage of DC microgrid when it is normally on; In case of ground short-circuit fault in DC microgrid, the coupling energy of the short-circuit current makes the PMOS to be turned off reliably. In addition, because the primary inductance of the transformer plays a certain current limiting role, the turn-off current of PMOS will not increase sharply. The solid-state circuit breaker can effectively block the fault without a buffer circuit, which has a good application prospect.