Line-model consistency based pilot protection for renewable energy lines

The rapid development of renewable energy sources (RESs) has brought a rapid increase in power electronic interfaces. Conventional pilot protection schemes for RES-connected lines exhibit significant limitations, necessitating the investigation of novel protection principles. This study proposes a pilot protection scheme formulated in the frequency domain (FD). The proposed method establishes a concise criterion for distinguishing internal from external faults by characterizing the line model integrity metric (LMIM). This criterion is based on a distributed and frequency-dependent line parameter model, which captures the relationship among voltage, current, and surge impedance during fault transients. Furthermore, the numerical Laplace transform (NLT) is utilized to compute the discrete criterion in the FD. Finally, the comprehensive protection scheme is presented. The validity of the proposed method is verified through comprehensive simulation studies and experiments. Furthermore, the performance of the proposed method under nonideal conditions such as measurement noise and parameter deviations has been evaluated, demonstrating its strong robustness. Compared with existing approaches, it offers superior applicability and high tolerance to fault resistance.