Method of detecting partial discharge using frequency spectrum analyzer

Abstract

A method of detecting a partial discharge signals occurring at an insulator, using a Frequency Spectrum Analyzer (FSA) with a monitor screen. The method including the steps of setting a horizontal axis of the monitor screen as a time axis and a vertical axis as an axis representing a voltage magnitude; receiving a power frequency signal having phase angle and carrying the partial discharge signals derived from the insulator being tested, to display the magnitudes of the partial discharge signals based on the time axis; detecting each of the maximum value of the partial discharge signals being displayed by the receiving step, to cause them to be evaluated into coordinate values of the horizontal axis and the vertical axis discriminating each of the phase angles of the power frequency signal based on the coordinate value of the horizontal axis detected by the detecting step, and evaluating each of the magnitudes of the partial discharge signals positioned at respective phase angles of the power frequency signal based on the coordinate value of the vertical axis; and overlapping each the phase angle of the partial discharge signals positioned at the respective phase angles evaluated by the discriminating step with each other according to corresponding phase angles, and comparing them relative to each other, such that the magnitude and number of the partial discharge signals appearing at the respective phase angles of the power frequency signal can be evaluated.