Investigating DC Faults in DC Distribution System with Converter Centre Grounding

The DC voltage of the DC distribution system is supplied from the AC side, so it is necessary to consider the hazards caused by faults in the AC power system. In this paper, according to the typical “double petal ±10kV DC distribution system”, a system model is constructed by using the Matlab/Simulink simulation platform, and the operation mode of the converter capacitor mid-point direct grounding is considered, and some effects on the AC side under DC unipolar grounding fault are mainly discussed according to the constructed simulation. The operation mode is considered to be the direct grounding of the mid-point of the converter capacitor, and some effects on the AC side under the DC unipolar grounding fault are mainly discussed according to the simulation model, and the steady state operation characteristics of the DC voltage and power of the DC distribution system with the converter mid-point direct grounding are obtained, in which the fault pole voltage rapidly drops to zero and the non-fault pole voltage rises to the interpolar voltage in the case of the capacitor mid-point direct grounding mode.