METHOD OF DETERMINING LOCATION OF SINGLE-PHASE EARTH FAULT IN A POWER DISTRIBUTING NETWORK

摘要

The present invention concerns a method of locating a ground fault in a power distribution network, in which method the start instant of the fault transient is determined from the change of the neutral point voltage, the current and voltage transient signals of the faulty phase are filtered, the duration of the transient is determined, the frequency of the fault transient waveform is estimated, the measured voltage and current transient signals are low-pass filtered, the spectra U( omega ) and I( omega ), of the voltage and current transients are computed, the impedance spectrum (1) is computed, and the estimate of the fault distance is computed for a discrete angular frequency omega k from the equation (2). According to the invention, the voltage and current signals of the faulty phase are filtered using a comb filter, the measured voltage and current signals are low-pass filtered in two directions, the frequency of the charge/discharge transient is estimated from the autocorrelation function of the transient, and the complex value spectra U( omega ) and I( omega ) of the voltage and current transients are computed using parametric spectral estimation methods.