Investigation into the effects of different antenna dimensions for UHF detection of partial discharges in power transformers

Detection of partial discharges (PDs) in power transformers can be seen as a means of anticipating imminent transformer failure and thus saving the transformer through planned maintenance. This work focuses on a ultra high frequency (UHF) technique for PD detection. A UHF antenna, capable of being fitted onto a standard DN5O transformer drain valve while maintaining an oil-tight seal, was designed for the purposes of this work. A surface discharge defect was created in the laboratory to study the effects that different antenna dimensions would have on the detected wideband UHF signal and determine an optimum frequency at which the defect can be detected.