Single Ended Fault Location of MMC-HVDC Lines Incorporating Traveling Wave and Model Information

This paper presents a single ended fault location (FL) scheme for MMC-HVDC transmission lines. The proposed method works with a relatively low sampling rate of 20kHz, which corresponds to insufficient time resolution and generates large systematic error if applying traveling wave (TW) based FL methods. The proposed FL method can be seen as a fusion of TW based methods and model based methods. To mitigate the impact of fault resistance (FR) on FL accuracy, the fault current contribution from the remote end is accurately compensated based on the MMC equivalent source model. Specifically, since the MMC equivalent source model at the remote end is activated exactly when the TW arrives, the insufficient time resolution with the relatively low sampling rate will cause FL error. To tackle this challenge, the TW arrival time can be further fine-tuned by incorporating model information, enabling accurate FL even during high resistance faults. Simulation results verify that the proposed approach presents small fault location errors during both low resistance faults (LRFs) and high resistance faults (HRFs), and demonstrates robustness towards measurement noises and parameter errors.