Analysis of the Influence of Ambient Temperature and Load Rate on Transformer Hot-Spot Temperature

Power transformer is an important equipment in the power system, and its operation status directly affects the safety and stability of the power system. Hot spot temperature is one of the important indicators to measure the operating status of transformers, and too high hot spot temperature will lead to insulation aging, shortened equipment life and even short circuits. In actual operation, the ambient temperature and load rate will have an impact on the hot spot temperature of the transformer. In order to analyze this rule, a 220kV three-phase oil-immersed power transformer was taken as the research object, and a two-dimensional axisymmetric model of the transformer was established through ANSYS FLUENT, and the heat flow field was analyzed to obtain the internal temperature distribution of the transformer at ambient temperature of 15 °C~45 °C and load rate of 0.8”, 1.2, and the parameter sensitivity analysis of hot spot temperature was carried out. The results show that the influence of the square of ambient temperature and load rate on the hot spot temperature of the transformer is basically linear, and the coupling effect of the two is weak, and there is a certain saturation effect on the increase of hot spot temperature under high ambient temperature and high load rate.