Partial discharge localization in transformers using monopole and log-spiral UHF sensors

Abstract

The location of a partial discharge (PD) source inside a transformer can be determined from the time differences of arrival (TDOA) between signals that are captured by an array of UHF sensors. From these, the PD location can be found by geometric triangulation which involves solving a set of non-linear equations. This can be achieved using an efficient software realization of the maximum-likelihood estimator. The recorded PD waveforms are affected by the type of sensor used to capture PD signals. In this paper, the accuracy of the PD localization using different sensors is investigated. Two types of sensor, i.e. short monopole and log-spiral are used to capture electromagnetic waves emitted from a PD source. To calculate the TDOA, two methods: first peak and cross-correlation were applied. The localization result shows the monopole sensor produces higher accuracy than the log-spiral and the first peak method achieves better result than the cross-correlation method.