Determination Of Faulted Line In No-Direct Ground Neutral System Based On Multi-Fractal Spectrum

When a single phase-to-earth fault occurs on a neutral non-directgrounded power system, it is necessary to give a alarming and select thefaulted line quickly. But, there exist some problems on selecting the faultedline in the system. A new method for diagnosing single phase-to-earth faultsis presented, which is based on multi-fractal spectrum calculated bycomputer emulator.Firstly, a detailed analysis to fault transient course of the system ismade. And then some methods for selecting fault line used in our country orabroad are introduced. After that, the emulator of MATLAB to an unhealthysystem is applied and the multi-fractal spectrum of the zero-sequencecurrent of the system is achieved. At last, focusing on a resonance-groundedpower system, a method of selecting faulted line based on multi-fractalspectrum of the zero-sequence current is presented.The multi-fractal spectrum of a signal reflects its geometry features,and the wavelet local maxima modulus based method is received moreattention because it can calculate the multi-fractal spectrum effectively andsimply, The result shows that the geometry features of a fault current signalcan be reflected by multi-fractal spectrum, which provides an effective wayfor selecting faulted line on a neutral non-direct grounded power system.