Theoretical Calculation, Simulation and Experimental Analysis of Cavitation Threshold of Transformer Oil

Abstract

Bubble is a serious threaten to the insulation performance of oil-paper insulation system in oil-immersed transformer. The vibration will cause alternating pressure changes in oil and then produce cavitation bubbles. However, the cavitation threshold have not been studied in the electrical field. In this paper, the cavitation threshold in transformer oil is calculated by using the relevant theories of fluid mechanics and bubble dynamics, and then the cavitation threshold under different gas contents is obtained by combining experiment and simulation. It is found that the two results have good consistency. The results show that the cavitation threshold of transformer oil decreases with the increase of gas content and temperature, but presents a certain saturation characteristic with the increase of gas content.