ABSTRACT
The partial discharge is an important index to reflect the insulation performance of electrical equipment. The ultrasonic signals generated by the board can be used to check the location of the discharge [1]. The ultrasonic method is seldom used in partial discharge test because of its low sensitivity. But the sensitivity of ultrasonic measurement has been greatly improved since the improvement of the sensitivity of energy exchange components and the application of low noise integrated amplifier in the last twenty years [2]. In addition, the ultrasonic tester can eliminate the external electromagnetic interference and can effectively determine the part of the partial discharge. Therefore, the ultrasonic testing method has been widely used in the high voltage electrical equipment with complex structure.
