Survey of DC Side Fault Characteristics in VSC-MTDC System

Analyzing the characteristics of the fault in VSC-MTDC system can help to quickly identify the kind of it and eliminate its effect in time, in order to avoid further damage of the whole system, which protect the grid operating safely. In this paper, a four-terminal VSC-MTDC simulation platform was built for study based on Matlab/Simulink. Different kinds of faults were set on the DC line, and their fault characteristics were compared. Particularly the single pole grounding fault with the highest frequency of occurrence is studied in detail, including the effect of DC side capacitance, smoothing reactor, grounding resistance and the location of faults on the line, which provides a reference for the future design of grid code requirements related to VSC-MTDC system.