Fault Detection and Isolation Technique in Low Voltage DC Microgrid Based on Terminal Resistance of DC Circuit Breakers

Nowadays research on DC microgrids (DCMG) focuses mainly on power/energy management, control and optimization in architecture. While research on the protection of the DCMG has got the attention lately. A DCMG is considered to be healthy when it is working in normal condition. This DC microgrid faces a problem when a fault occurs in the system. Many protection methods have been reported to protect the DCMG, some of them are based on communication among the converters and DC circuit breakers. As a result, cost increases and the chance of failure of communication link increases which leads to a protection scheme into danger. A protection scheme against any fault in DC microgrid relies on the operation of DC circuit breakers and its fault clearance time which depends on the speed of the circuit breaker. In this paper, a method based on the resistance at DC circuit breaker terminal has been investigated. This method calculates the resistance across each DC circuit breaker terminal and based on this value, the controller takes a decision for a dedicated circuit breaker in order to operate to isolate the faulty section. This method has been simulated in MATLAB/Simulink environment and results show the performance of this method. To know the contribution of sources to feed the fault, mathematical analysis has also been carried out.