A Fast Directional Protection Based on Positive-Sequence Pseudo-Fault Power

Traditional directional protection methods suffer from relatively long fault discrimination times, making them increasingly difficult to meet the higher fault isolation speed requirements of modern power systems. To address this issue, this paper proposes a fast directional protection principle based on positive-sequence pseudo-fault power. The paper first analyzes the characteristic differences between internal and external faults in a double-end power supply line, exploring the mapping relationship between fault phase angle differences and reactive power. Then, based on the instantaneous sequence component decomposition method, the positive-sequence pseudo-fault power for AC systems is constructed and defined. Furthermore, by incorporating integral operations, a fast directional protection principle based on positive-sequence pseudo-fault power is proposed. The proposed protection can identify faults within 5 ms and exhibits robustness against transition resistance and noise interference. Finally, simulation tests conducted on the MATLAB/Simulink platform thoroughly validate the rationality, effectiveness, and advantages of the proposed protection compared to other directional protection methods.