Partial Discharge Detection in Oil-Immersed Power Transformers Using Innovative UHF Sensor

Oil-immersed power transformers are one of the most essential elements in electric power networks. Partial discharge is one of the most important problems facing these transformers, which may lead to insulation failure. In this paper, a new ultra-high frequency sensor is manufactured, and its performance, specifically its suitability for PD detection inside power transformers, is investigated thoroughly. The sensor is based on a microstrip antenna design, and its simulation results provided satisfactory performance for PD signal detection in oil-immersed transformers. The UHF sensor performance is investigated and tested experimentally for PD detection in an oil tank, the corona discharges in air gaps, as well as the surface tracking UHF signals of the leakage current bursts on the surface of the polymer insulator, and has proven highly accurate in capturing the UHF signals in both cases. FFT was generated for the captured UHF signals, and the results are used to identify the type of UHF signal. This helps in the discrimination among different types of sites.