METHOD FOR DETECTING HIGH IMPEDANCE FAULT THROUGH WAVELET TRANSFORM AND METHOD FOR MEASURING FAULT DISTANCE OF THE SAME

摘要

PURPOSE: A method for detecting high impedance fault through wavelet transform and a method for measuring fault distance of the same are provided to detect a fault of a transmission line and measure a fault distance accurately by performing a signal analysis through a wavelet transform about an over voltage and current generated in a high impedance fault. CONSTITUTION: A first process(S100) converts an analog signal of a three-phase voltage and current including an inputted fault phase into a digital signal. A second process(S200) performs a filtering through a secondary butterworth low pass filter to extract an N-th harmonic wave component from the converted digital signal. A third process(S300) performs a wavelet analysis about the filtered signal. A fourth process(S400) judges if a sum of each phase current is within a fault detection area, and generates a trip signal to detect a fault.