Partial discharge diagnostics in power and instrument transformer based on acoustic emission method

Power and instrument transformers represent important components of electric power transmission and distribution stations. An important indicator of the condition of the insulation of such equipment is the evolution of the partial discharge (PD) level, since an increase of this level usually indicates the development of a fault affecting the insulation quality. Detection of partial discharges in the early stages reduces the risk of decommissioning of such equipment. A well known method for detecting and locating of partial discharges is the acoustic emission method. This article is an overview of the thirty years' experience of the use of this method in ICMET, which resulted in the development of the necessary equipment for monitoring and location of partial discharges in power and instrument transformers.