Investigation of Partial Discharge Localization Method for EHV Prefabricated Joint

For Partial Discharge (PD) measurement, not only detecting the signal magnitude of PD is enough for evaluating the insulating constructions of HV equipment such as GIS, GIL, power cable, and cable joint, but also localization of the PD position is important to them. PD localization can help to find out the defect point effectively and determine the cause of PD, improve the manufacturing process, and increase the insulating properties. This paper describes multiple new methods of PD localization including 1) use of metallic foil electrode sensors, 2) excitation of X-ray radiation, 3) application of acoustic emission sensor, applied to a EHV prefabricated joint in a length scale of about 2m long. Comparing with the conventional PD localization for long size of cable, it is more difficult to locate a PD for the short size of joint due to the pulse reflection, the pulse propagating route and the difference of propagating velocity, based on the materials and shape of the part units of the joint. Several successful PD localization shown that the method can locate PD with sufficient accuracy.