The Investigation of Detect Position of Partial Discharge in
Cast-Resin Transformer Using High-Frequency Current
Transformer Sensor and Acoustic Emission Sensor

Abstract: The lifetime of a cast-resin transformer mainly depends on the condition of the insulation
material. Partial discharge (PD) is an important reason for insulation deterioration in cast-resin
transformers. Identifying the position of PD is very necessary for damage assessment while the
transformer is still operating, and the transformer is covered by housing. This paper proposes the
investigation of a cast-resin transformer using an AE sensor and HFCT sensor to specify the precise
source of PD. In this study, four AE sensors were used to find PD sources and the high-frequency
current transducer (HFCT) technique was used to identify the PD source and the criteria level. The
experiment, in the first two parts, identified the possibility of PD, which includes the position of PD.
The final part of the experiment verified the position of the PD source of a cast-resin transformer
and confirmed the inspection results. AE and HFCT sensors can be used to detect the location of
PD sources, confirming the position of the PD source by sensor detection. In addition, the evident
partial discharge picture on the insulator surface of the high voltage side. The process successfully and
accurately identifies and locates the PD source.