A three-phase adaptive reclosure technology for distribution feeders based on parameter identification

A scheme is proposed to improve the decreasing success rate of reclosing in a non-effectively grounded system with a wide application of cables. An inverter source is momentarily connected to the low-voltage side of a service transformer by controlled thyristors to apply a transient high voltage to the de-energized feeder before reclosing. Based on the idea of parameter identification, the internal structure of the de-energized feeder is investigated according to the frequency characteristics of the reference parameters to determine whether the feeder still experiences the fault. The influence of the firing angle on the strength of the frequency components in the transient waveforms is analyzed to determine its range for accurate measurement of feeder harmonic impedance. A sensitivity analysis on the fault property detection criterion is conducted, and the selection of the inverter source power impacted by the firing angle is provided. The results of the theoretical analysis, computer simulation, and lab experiments confirmed the effectiveness of the proposed scheme.