Robustness of a generalized impedance based fault locator considering distorted measurements

Abstract

Power quality is a relevant aspect in power distribution systems, which among others, considers service continuity and distortion of the current and voltage waveforms. This paper proposes a generalized application strategy of an impedance-based fault location method for power distribution systems and also analyses the effects of the waveform distortion on its performance, by comparing the location errors in the case of distorted and not distorted measurements of voltages and currents. Different sources of waveform distortion, such as transformer saturation, low resolution of the measuring devices, harmonics, low sampling frequency, signal noise and DC offset are analysed. According to the obtained results, the worst performance of the fault location method is obtained in the case of distortions caused by current transformer saturation. An additional circumstance of reduced performance is in such cases of simultaneous presence of low sampling rate and high harmonic distortion. Finally, the analysed values of resolution, signal noise, presence of DC offset and potential transformer saturation, cause a negligible reduction on the locator performance.