Localizing partial discharge in power transformers by combining acoustic and different electrical methods

The reliability of electrical systems depends on the quality and availability of the power apparatus. Power transformers are important nodes in the electrical power grid. Common reasons for breakdown are problems in the insulation system. Detecting partial discharge in the insulation system of a power transformer at an early stage reduces the risk of total breakdown of power apparatus. One method to detect partial discharge is the acoustic measurement. With this technique a detection and localization of partial discharge is possible by placing acoustic sensors on the surface of the transformer tank. The low level of electrical interferences from outside the measurement setup constitutes one of the strengths of this method. A further advantage is the ability of identifying the position of the partial discharge source, which is needed to estimate the risk and to enable a fast and effective repair.