Zero Mode Analysis of Single Pole to Ground Fault in the DC Distribution Networks

In this paper, based on the 32-node DC distribution network model, we analyze the zero-modulus nature of single pole to ground faults in DC distribution networks, and the specific research contents are as follows: establish a simulation model of DC distribution networks and analyze the zero mode nature of faults, compare and analyze the system structure and grounding mode of DC distribution networks, and based on the fault characteristics of DC distribution networks when a single pole to ground fault occurs, we use the phase-mode transformation method to decouple the transient components of faults into modal components, and analyze the single pole to ground fault and analyze the modal components of unipolar faults. Modal components are decoupled into modal components using the phase mode transformation method to analyze the unique zero mode nature of single pole to ground faults. The zero mode equivalent models of Modular Multilevel Converter (MMC) and DC/DC converter are constructed, and the zero mode equivalent impedance of the converter is deduced, and a 32-node DC distribution network simulation model is constructed in PSCAD/EMTDC for the simulation verification and analysis of the single pole to ground fault, and a single pole to ground fault simulation of the DC line is obtained. Fault characteristics of the single pole to ground fault.