Monopolar Fault Reconfiguration for Resilient Protection of Bipolar DC Distribution System

In bipolar DC distribution system, a ground fault on a single line can easily cause a chain fault on the non-fault pole. To reduce the disturbance of such faults on the system, this paper analyzes the influence mechanism of two factors on the monopolar fault reconfiguration. The two factors are the power shortage on the non-fault pole and the protection delay of the voltage balancer. To reduce the disturbance of these factors on the non-fault pole, this paper proposes a non-fault pole load shedding scheme and voltage balancer protection scheme based on di/dt of the fault current. Finally, simulation verification was carried out in MATLAB/PLECS, and a bipolar DC distribution system experimental platform was built. The simulation and experimental results verify that the proposed monopolar fault reconfiguration scheme can effectively improve the supply reliability of the bipolar DC system.