An investigation of discharges in oil insulation using UHF PD detection

In this paper, partial discharge (PD) is generated using a range of electrode configurations in an oil insulated system. High voltage AC at 50 Hz is applied to each test configuration and the PD activity is recorded using an ultra high frequency (UHF) monitoring system. The PD signals are analysed in a phase resolved form, from which the corresponding statistical distributions are determined. The results indicate that different defect types can be distinguished on the basis of their phase-resolved patterns measured at UHF. Possible physical causes for the discharge patterns are discussed