Investigation of partial discharge localization method considering internal structure of static capacitor by acoustic emission method

About 50% of the high-voltage (HV) static capacitors (SC) have been operating for more than 30 years by the beginning of the 2010s. Most of them are oil-immersed paper capacitors. For their efficient maintenance and management, it is necessary to establish an on-site partial-discharge (PD) diagnosis of the capacitors. In this paper, acoustic emission (AE) method is selected from the view point of PD detection sensitivity for SC and applicability for the on-site PD diagnosis without any interruption for continuous SC operation. PD localization technique for SC using plural AE sensors is developed in this paper. PD localization method utilizing information of internal structure of SC is proposed to improve the accuracy of PD localization by AE sensors in concrete terms. This proposed method applied to PD test for an aged SC operated for 48 years and removed from the actual substation. A number of carbonizations formed by PD were found inside the aged SC at the dismantled test after the PD test. Then, As compared with the accuracy of proposed PD localization method and traditional one, accuracy of proposed one improves by 60% to the traditional one. © 2016 The Institute of Electrical Engineers of Japan.