Abstract:In order to overcome the shortcomings of the existing partial discharge tester for GIS equipment,the design concept of adding detachable extendible insulating pole,fixed component of ultrasonic sensor,connecting component of sensor and insulating pole,wireless transmission signal component and fixed base of extendible insulating pole is presented without changing the structure of the original ultrasonic tester. After assembly,the device is applied to a substation. The field test data show that compared with the traditional device,the deviation of field test data is small,which saves the time,improves the work efficiency and avoids the climbing operation for the staff.