Simulation of Propagation Pattern of Partial Discharge’s Ultrasonic Signal in Oil-Immersed Transformer

The breakdown of insulation caused by partial discharge inside the transformer is an important cause of transformer failure. Ultrasonic detection is a common method for detecting and positioning partial discharge in transformers. According to the needs of rationally arranging ultrasonic sensors and optimizing the positioning algorithm, this paper carries out a simulation analysis of the propagation pattern of partial discharge ultrasonic signals inside the oil-immersed transformer. Based on the finite element simulation software, an oil-immersed transformer model was built, and different geometric structures and material parameters were designed for the transformer’s box, iron core, winding, and oil. The propagation mode of the partial discharge occurring in the oil passage between the high and low voltage windings, the high voltage winding and the outside of the winding in the transformer is analyzed, and the attenuation of the partial discharge ultrasonic signal in the transformer by the winding is studied. This article provides a certain reference for the layout and optimization of built-in ultrasonic sensors in oil-immersed power transformers.