Fault Location Algorithm Based on Cross Correlation Method for HVDC Cable Lines

In this paper, a fault location algorithm using travelling waves and a cross correlation method is proposed for HVDC cable lines. The arriving instants of the first fault-induced transient backward travelling wave and its subsequent reflected wave can be detected by using a cross correlation method. The fault distance is estimated by using the time difference between the two instants of incident waves and the velocity of the travelling wave. Because the fault-induced backward wave is much similar to a square wave when a fault occurs in the HVDC cable lines, a kind of step function is used as the reference function for the cross correlation in this paper. The proposed algorithm was verified with varying fault distances and fault resistances in submarine HVDC cables connected to the current source converter (CSC) type HVDC system and the voltage source converter (VSC) type HVDC system respectively.