Abstract
Based on the analysis model of single-pole to ground fault occurred in single-ended MMC DC distribution network, the characteristics of single-pole to ground fault are studied. The similarity of positive and negative current between the fault feeder and the non-fault feeder, the similarity of fault current between the fault feeder and the non-fault feeder, and the similarity of positive and negative current sum between the two feeders are analyzed. Based on the differences among the three types of similarity, a new method of single-pole grounding protection for DC distribution network with MMC based on multi-type similarity analysis is proposed. The simulation results show that this method can accurately determine the fault feeder, and has the characteristics of strong anti-interference ability, simple calculation and easy implementation. It can effectively solve the problem of single-pole grounding protection of DC distribution network and effectively improve the safety and reliability of power supply of DC distribution network.