ELECTRICAL LEAK DETECTING APPARATUS AND ELECTRICAL LEAK DETECTING METHOD FOR IMPROVING THE ELECTRICAL LEAK DETECTING ACCURACY

摘要

An electrical leak detecting apparatus is disclosed according to an exemplary embodiment of the present disclosure. The earth leakage detecting apparatus may include a ground voltage measuring unit measuring ground voltage, an ADC unit sampling the measured ground voltage and converting the measured ground voltage into a digital value, and an effective value calculating unit calculating an effective value of the ground voltage converted into the digital value. A Fourier transform unit for performing a Fourier transform on the measured ground voltage based on the effective value of the ground voltage and calculating a voltage for each harmonic component that is an integer multiple of a fundamental frequency—the power frequency of an AC commercial power source; and based on the voltage for each harmonic component. A content calculation unit for calculating a voltage content ratio of the fundamental frequency to a voltage obtained by adding the voltages for each harmonic component, and a total harmonic distortion factor and a distortion factor for each harmonic component based on the voltage for each harmonic component; A harmonic distortion rate calculating unit for calculating a value, and converting the digital value into the digital value for a predetermined time T1. A zero crossing calculation unit for calculating the number of zero crossings through which a ground voltage passes a zero voltage and an effective value of the ground voltage, the voltage content rate, the total harmonic distortion rate, the distortion rate for each harmonic component, and the zero On the basis of at least one of the number of crossings, the ground voltage is determined to be caused by the leakage of the AC commercial power supply, and based on the determined result, the ground fault to determine the area in which the ground voltage is measured as a suspected short circuit region Suspect zone determination may be included.