An Improved Spatial Intersectional Method for Partial Discharge (PD) Source Localization in Power Transformer

Partial discharge (PD) measurement is one of important techniques for condition assessment of a power transformer. One major task of PD measurement is PD source localization using acoustic emission (AE) sensors. In this paper, an improved spatial intersectional method is proposed for an effective PD source localization in power transformer. To understand the impacts of multiple possible propagation paths of acoustic signals (induced by PD activity) on PD source localization, the time-of-arrivals (TOAs) of acoustic signals travelling along different paths inside a transformer tank are investigated. Especially, Savitzky-Golay (SG) filter is implemented for determining the TOAs from a number of AE sensor measurements. Based on the acquired TOAs, a three-dimensional (3D) spatial intersectional diagram is constructed. It can determine a possible area within a transformer tank, in which PD source may exist. The proposed method is tested on a transformer using three AE sensors and a high frequency current transducer (HFCT).