A Dual-Window Transient Energy Ratio-Based Adaptive Single-Phase Reclosure Criterion for EHV Transmission Line

A criterion of dual-window transient energy ratio (ER) to improve the adaptability of the self-adaptive autoreclosure of transmission line is proposed. The redundancy of setting of the criterion can be enhanced in comparison with the criterion of single-window transient energy. To effectively extract the high-frequency energy of the voltages, a novel concept of close-opening - open-closing morphological gradient (COOCG) is put forward. Compared with the multiresolution morphology gradient transform, COOCG has a lower unbalanced output when processing the steady-state signal; therefore, the threshold of ER can be lowered to improve the successful rate of fault discrimination. EMTP-based simulation results show that the COOCG-based autoreclosure scheme improves the reliability of discrimination and is promising to be used in the real power systems.