The Partial Discharge Locating Experimental Study in Transformer Based on Ultrasonic Phased Array

Partial discharge locating detection is a key project in transformer insulation mechanism research and quality control. And it is an important foundation in transformer´s condition maintenance. The theory of partial discharge location based on ultrasonic array is an effective improvement of partial discharge locating. But in experimental studies, the problem of sensor array element coupling performance is inconsistent, the results of many cross-point locations are also different, and the success rate and the locating accuracy in double-platform locating are not better than imagined. Based on these problems, three practical methods and techniques are presented in this paper. Firstly the pencil test method is used to test the coupling performance of the elements of the array sensor to improve the success rate of localization; secondly, taking repeated measurements at the same place and the weighted average method to improve the accuracy of measuring; thirdly the multi-platform and global search method are used to improve the positioning accuracy of PD source locating. Finally, the locating experimental system is established based on the ultrasonic phased array in oil. The Experimental results show that the locating errors is less than 10cm, verifies the three methods can effectively improve the partial discharge array ultrasound locating success rate and locating accuracy.