Simulation Analysis of Partial Discharge Signal Propagation in Transformer

Insulation fault is the main form of power transformer fault, and partial discharge is an important manifestation of insulation fault. During the partial discharge detection of transformers, different detection points are usually selected. When the same discharge signal is transmitted through the transformer windings to different detection points, it will be affected by the winding structure and propagation characteristics. Therefore, the measurement results of the same discharge signal at different detection points are also different. In this paper, a transformer simulation model is established to study the propagation characteristics of partial discharge signals in the transformer. Firstly, a single transformer winding model is established to discuss the frequency characteristics of the transformer winding. The parameters in the transformer equivalent model are affected by the transformer winding form, insulation material, capacity, transformer core material and other factors. This paper analyzes and compares from different angles of the capacitance element and inductance element, and studies the influence on the frequency-domain characteristics of the transformer winding, so as to provide theoretical basis for the reasonable measurement bandwidth of ultra wide band partial discharge detection. Secondly, a complete simulation model of a 35kV single-winding transformer was established. The simulation analysis tool was used to analyze the partial discharge signal emission of each detection point, and the differences between different detection points and different partial discharge power supply positions for the detected signals are compared, the velocity and amplitude variation of pulse current signal in transformer are obtained.