Fault detection and location for MTDC combining wavelet analysis and travelling wave

Multi-terminal HVDC has been taken seriously for its economical and technological advantages. However, MTDC meets a bottleneck that the VSC, based on IGBT, is destructively vulnerable to the fault on DC side. Consequently How to fast detect and precisely locate them weighs much in MTDC fault clearing. A method combining wavelet analysis and travelling wave is proposed in this paper. We use wavelet packet analysis to detect the type of fault and find in which DC line the fault occurred, by building a one-to-one mapping from fault signal energy change to fault. The simulation in MATLAB/SIMULINK shows the idea is feasible. Afterwards a mathematical model of travelling wave is constructed to locate fault for farther accuracy, thus completing the DC side fault detection and location system in MTDC.