Investigating suitable positions in power transformers for installing UHF antennas for partial discharge localization

One of the critical points in the UHF partial discharge (PD) localization in power transformers is the installation position of the UHF antennas inside the transformer or on its tank. In the UHF localization method which is based on comparing the differences of the arrival times of the partial discharge electromagnetic waves, ideally at least four antennas must be used to have an effective localization. Mechanical limitations such as the existence of iron tank and high electric field intensity inside transformer must be considered in installing UHF antenna. Beside these problems, the effect of antennas positions on localization accuracy must be taken into account. The positions of the antennas have a direct relation with arrival time differences for potential PD positions inside transformer. In this paper a method to identify best places for antennas installation is proposed to obtain more accurate defect localization.