High Voltage Direct Current (HVDC) system was often the link between major power grids. In order to ensure the safe operation of HVDC, fault diagnosis method was studied. The system structure of HVDC Light system was analyzed, and the normal and fault conditions of the transmission system were simulated in the Matlab platform. This method was very convenient and simple, and it could restore the real situation. The use of simulated waveform could effectively identify the fault types of actual situation, and then it was a flexible, efficient and practical method of fault diagnosis in HVDC Light system.
