ASYMMETRICAL FAULT DETECTION IN DE-ENERGIZED DISTRIBUTION FEEDER

Abstract

After maintenance or repairing of the de-energized distribution feeder there is need of safely energizing of feeder for the utility’s safety. The safely energizing can be done by determining the fault exists on the distribution system before energizing the system again. The fault detection in de-energized distribution feeder is more difficult than the energized distribution feeder since it requires the system level voltage production and execution to the downstream. Here we implemented an asymmetrical fault detection method to detect the fault before re-energizing the distribution feeder. A controllable signal is feed into de-energized distribution feeder using a thyristor based device to generate the electrical response. The strength of signal can be adjusted from low to high to detect low impedance fault at the beginning, since the maximum faults on distribution system are low impedance faults. A low strength signal may act as an alarm to the personnel or animal in contact with the live part of the system so that they can get away from the system to avoid getting sudden electric shock. Also the major faults on distribution systems are asymmetrical faults so it is necessary to identify and detect the asymmetrical faults before Re-energizing the feeder. The detection and classification of different asymmetrical faults is also explained in this paper. For the determination of the faults we are analyzing the voltage and current signals of the downstream feeder. The fault detection algorithm and control strategies of thyristors are also described for different faults and analyzed by using computer simulation in MATLAB.