Identification criterion of permanent single-phase fault for transmission lines with shunt reactors

Based on characteristics analysis of resonant component under different system impedance for transmission lines with shunt reactors, this paper proposes a criterion using amplitudes of the resonant component and power-frequency component in the open phase current from shunt reactor to detect transient faults and permanent faults. In the case of a transient fault, the current from shunt reactor in the open phase consists of resonant component and power frequency component. But for permanent fault, the current contains power frequency periodic component. Therefore, a method uses a prescribed fitting function of the open phase current from shunt reactor to acquire the amplitudes of resonant component and power frequency component, and then utilizes the amplitudes character to distinguish the permanent faults from transient faults. The criterion is simple and reliable, as it only uses the open fault phase current with high precision. ATP simulations show that the criterion is correct and effective and can detect the nature of single-phase fault quickly, thus is promised to improve the success rate of the single-phase adaptive reclosure.