Abstract: This article analyzes the method of abnormal discharge of high-voltage through-wall bushings in substations under uninterrupted power condition, verifies the sensitivity and reliability of infrared accurate temperature measurement, ultrasonic local discharge detection and other live detection methods to abnormal discharge of high voltage casing,which can avoid tripping accidents in the differential range of the transformer.And a fully sealed round copper rod porcelain through-wall bushing is customized, which can solve the problem of abnormal discharge of equipment caused by moisture invading the through-wall bushing.