基于平面相交法的敞开式变电站多源局部放电定位方法

Recently, the ultra-high-frequency-based antenna array has been applied to partial discharge (PD) detection and localization in air-insulated substations (AIS). The range of PD source is generally estimated with high inaccuracy in most of the related instruments, and a localization algorithm which is applicable to the cases of multiple sources is not developed yet. We put forward a plane intersection method to localize multiple PD sources which may occur simultaneously in AIS. The time difference of arrival (TDOA) between antennas is estimated with the cross-correlation (CC) method, in which the CC function is interpolated with minor time interval to improve the TDOA accuracy when an acquisition instrument with low sampling rate is adopted. Thereafter, the time difference equations are solved with the plane intersection method, and the final localization results are determined as the one with highest probability among numerous signals. In the case of multiple PD sources, the K Means clustering algorithm is applied to TDOA vector of antenna array to separate UHF signals. A PD detection and localization experimental system is developed and used to test the accuracy of the proposed algorithm. The results indicate that, for diamond array with size of 4 m×2 m and PD sources within range of 10 m and 45° to normal line of antenna pair with distance of 4 m, the localization error is less than 1 m in all cases and 20 cm in most cases. Moreover, the localization accuracy for multiple PD sources are close to that of one source.