Fault Location of VSC Based DC Distribution Network Based on Traveling Wave Differential Current With Hausdorff Distance and Cubic Spline Interpolation

Compared with AC power system, DC distribution network is a low-damping system without natural zero crossing. The DC fault current will reach its peak value within a few milliseconds, posing a great threat to power electronic devices. Therefore, the rapid and high-precision identification of DC line faults is one of the technical difficulties faced by the VSC based DC distribution network. In this paper, a new fault location method based on traveling wave differential current with Hausdorff distance and cubic spline interpolation is proposed. First, the forward and reverse traveling waves at both ends of the VSC based DC lines are extracted, the Karenbauer transform is used to decouple the positive and negative electrodes to obtain accurate fault information. Then, the internal relationship between the differential current and the fault current is obtained according to the principle of traveling wave transmission invariance, the cubic spline interpolation algorithm is used to solve the traditional sampling frequency limitation, and the positive differential current in the interception time window is smoothly displaced. At last, the Hausdorff distance algorithm is used to analyze the correlation between the translational differential current and the reverse differential current. The fault location corresponds to the highest correlation. The proposed method uses the time-domain information at both ends of the VSC based DC lines, and it is less affected by the transition resistance. Lots of simulation experiments prove that it has a strong anti-noise interference ability and high reliability, and is less affected by the sampling frequency after cubic spline interpolation. Compared with traveling wave algorithm based on Pearson correlation coefficient, the method in this paper shows a significantly shortened error, 27% on average.