A Novel Adaptive Reclosure Criterion For EHV Transmission Line

Autoreclosure schemes have been widely used in power system and an effective way to improve greatly the dependability and stability of power systems. However, most of these schemes adopt a presetting time to reclose breaker after a tripping operation. There are many problems due to the conventional reclosure schemes. In this paper, a self-adaptive auto-reclosure criterion using dual-window transient energy ratio (ER) for transmission line is proposed. A novel concept of close-opening - open-closing morphological gradient (COOCG) is put forward. COOCG has lower unbalanced output when processing the steady-state signal, and a better performance in extracting of high-frequency(HF) energy of the voltages, therefore, the threshold of ER can be lowered to improve the successful rate of fault discrimination. Many simulation results for the models established with EMTP show that COOCG is promising to be used in the real power systems.