Novel Partial Discharge Location in Cast Resin Transformer using UHF Method with Scanning X-ray Irradiation

Abstract

It is crucial to detect void and delamination which might exist in cast resin transformer, because these defects can reduce insulation performance of cast resin equipment. It is considered that detecting partial discharge (PD) is effective to diagnose equipment of power equipment. This paper presents novel PD location using X-ray irradiation and UHF method in actual 6.6 kV class cast resin transformer VT as well as sample simulating the defect. By scanning a copper plate installed in front of a X ray generator to limit the X-ray irradiation range, the defect position was successfully determined with 10 mm accuracy. it was also shown that PD source in a larger size 33 kV class VT can be located by the time of flight of the electromagnetic wave detection signal by UHF method.