Single-Phase Adaptive Reclosure of EHV Transmission Lines Based on Shunt Reactor Current Identification

Aiming at EHV transmission lines with shunt compensators, a novel technique is proposed to distinguish fault nature according to low frequency components in faulted phase current of reactor at the recovery voltage stage. In order to identify the magnitude of low frequency components, a energy function is defined which can determine the fault nature in 2~4 fundamental cycles rapidly and accurately. The characteristics of faulted phase current are analyzed in detail. For a permanent fault, the current contains power frequency and decaying slowly DC components. While for a transient fault, the current contains power frequency and low frequency components. Theoretical analysis and EMTP simulation prove that the proposed identification scheme can distinguish the fault nature exactly and improve the success rate of reclosure significantly.