Research on Partial Discharge Fault Characteristics and Key Parameter Testing of Oil-Immersed Current Transformers

The oil-immersed current transformers (OCTs) are widely used in the power system, in order to investigate the partial discharge (PD) characteristics of OCTs during operation, this study conducted PD tests on samples with intentionally introduced insulation defects. During the tests, the trends of expander height, bottom pressure, and top pressure of the product were measured as a function of the duration of applied voltage. Additionally, the characteristic gas content, breakdown voltage, dielectric loss factor, and moisture content of the oil samples were analyzed. Based on these measurements, the typical phenomena of PD faults in OCTs were summarized, which provides reference for on-line monitoring and fault analysis of OCTs.