One-End Method for Fault Location in Radial Distribution Network with DG

Abstract

Faulty zone in distribution network might be recognized by protective devices operation. Yet, precise fault point location is required for speeding up system repair. This paper proposes a travelling wave (TW)-based approach for locating faults in a radial distribution system integrating with DGs. Voltage signal at local end only required to be logged and then arrival times of first two TWs is determined. First, threephase signals are transformed into its equivalent aerial and ground mode signals in order to avoid fault type as well as faulty phase identification. Next, first-level discrete wavelet transform (DWT) is applied to the denoised mode signals to estimate the arrival times of the first two backward propagating TWs. For different possible fault zones, mathematical analysis of TW propagation diagrams is obtained to specify the second TW arrival at measuring site. So, broad-based equations are established to accurately estimate the fault position. The proposed approach has immunity to DG existence, fault type and resistance.