Comparison of Grounding Modes of MMC-Based Flexible DC Distribution Network

MMC-based DC distribution networks have a high power quality and power supply reliability, as well as a good compatibility with distributed generation. Meanwhile, there are many types of faults in the DC distribution networks, and the fault characteristics are complex and closely related to the grounding mode. Therefore, it is important to study the grounding mode. Firstly, the topology of DC distribution network is presented. Secondly, The fault characteristics of single-phase grounding fault both in AC side and the grounding fault on DC side are analyzed. The advantages and disadvantages of these grounding modes are discussed base on these fault characteristics. This paper will also introduce the scenarios of separate trial use of grounding methods, and provide references for the selection of grounding mode for DC distribution network.