Intelligent Short-Circuit Protection with Solid-State Circuit Breakers for Low-Voltage DC Microgrids

Fault current limiting (FCL) for short-circuit protection of DC microgrids (DC - mu Gs) is a challenging task due to the influence of power electronic converters on the fault characteristics. To overcome these challenges, a protection scheme needs to be developed which is capable of limiting the fault current, provides continuous power to the unfaulted sections in the network, and coordinates between the downstream and upstream protection devices. For the above-mentioned reasons, this paper analyzes the problems related to the protection of low voltage (LV) DC - mu Gs and to propose a solid-state circuit breaker (SSCB) based short-circuit protection methodology that provides FCL. To improve the action of the proposed approach, the conventional threshold-based fault detection approaches (FDAs) are replaced with an intelligent technique where decision trees (DTs) are used to learn the fault characteristics of the system. To evaluate the development of the proposed approach, numerical simulations are performed with a notational LV DC distribution system representing a DC - mu G. The simulation results and analysis proved the effectiveness of the proposed approach, and the FDA improves the operation of the SSCB and FCL with an accuracy of 98.3%. Further, the action of FCL function is tested on the reliability of the SSCB by analyzing the thermal characteristics of the device under both normal operating mode and the FCL mode.