Backup Protection Approach for HVDC Transmission Systems Based on Spectrum Analysis

In this paper, a backup protection approach for high voltage direct current (HVDC) systems is presented covering both pole-to- pole fault and pole-to-ground fault. The proposed approach relies on the spectrum analysis of the voltage and the current waveforms in the AC side exploiting the resulted distortion. The proposed approach is based on monitoring the 6
^th
harmonic component due to its significant existence under pole-to-ground fault. The 6
^th
harmonic component is obtained by Goertzel algorithm utilizing a window time of 3.3 ms. The proposed backup approach is superior to other backup protection approaches because it provides the backup protection against faults on all the HVDC systems items including converters, converters’ transformers, busbar, and transmission line. Sample results are recorded and investigated.