Fault Signature Analysis for Medium Voltage Overhead Line Based on New Characteristic Indices

Abstract

Medium voltage overhead line is exposed to fault due to the system spanning across a huge geographical area. The faults can lead to power outages and become a concern for power utilities. The outages can be due to various causes such as lightning strike, animal encroachment, and equipment failure. In some cases, the lightning strike might not affect the system as it self-clears and is represented as a lightning strike without fault. While, in other cases, a lightning strike with fault might present itself, thus, reducing the electrical performance. The impact of outages can be reduced if power utility operators utilize appropriate tools to analyze the fault signature. Several characteristic indices can be extracted from the signal waveform collected from Digital Fault Recorders (DFR) for practical applications. This paper presents fault signature analysis based on voltage and current parameters from the databases of overhead line system. Fault duration based on wavelet transform, rise time, decay time, and rate of change of neutral current are presented. The signature of lightning without fault, lightning with fault, and animal encroachment are established based on extracted characteristics.