Abstract
On-line fault location techniques of intermittent ground fault points on non-grounded distribution lines are necessary to supply steady electric power for customers. This paper proposes a novel method which uses frequency spectra of transient waveforms at a sending end when an intermittent ground fault occurs. The principle of this method is that if a ground fault position differs, it causes different frequency spectrum pattern of the current or voltage transients at a sending end which is decided by the surge reflection phenomena between the sending end and the ground fault point.
By comparison between experimental data of lLG fault test on a simulated overhead line (373m line length, 2 branch points) and digital simulation analyses, we found the grounded capacitance of a power source transformer was important enough to locate the ground fault point.
