Development of a model of a cooling system for a power oil transformer based on sulfur hexafluoride

Abstract

Relevance. New type of cooling of a power oil transformer with SF6 bubbles is proposed and therefore it is necessary to develop a mathematical model for selecting the optimal operating mode of a compressor bubbling SF6 gas. In the process of overheating of a power oil transformer, a cooling system is activated using floating SF6 bubbles, as a result, the pressure in the working area decreases, it becomes lower than the saturation pressure of the transformer oil with SF6 gas, i. e. when SF6 gas passes through the transformer oil inside the working area, an area of heat exchange of transformer oil, SF6 gas and transformer windings occurs. In this situation, each of the phases has a decisive effect on the creation of a thermal field in the working area, due to the manifestation of thermodynamic effects and the heat of degassing of the transformer oil. The formation of the temperature field is affected by various parameters: the local initial temperature on the transformer windings, the content of dissolved SF6 gas in the transformer oil, as well as the ratio of pressures in the transformer oil reservoir and the saturation pressure of the transformer oil with SF6 gas, etc. Thermal processes provide information on the current state of the power oil transformer. Aim. To formulate and solve the temperature problem of the transformer oil cooling. The object of the study is an industrial power oil transformer and a gas-insulated cooling system. Methods. One of the key aspects of ensuring the safety and efficiency of power oil transformers is the analysis of their temperature conditions. Under normal and especially emergency conditions of transformer operation, especially in gas-insulated cooling systems, transformer oil decomposes, which leads to gas formation. These processes cause changes in the temperature distribution inside the transformer, providing valuable data for diagnosing the causes of accidents. Results. The author has determined the dependences of temperature conditions on the operating time and operating conditions, which served as the basis for software development. Based on the identified patterns of heat transfer by SF6 gas in liquid insulators, it is possible to develop industrial solutions with adjustable diffusion and heat transfer parameters, as well as optimize the operating modes of these systems, taking into account the dynamics of chemical reactions and their rates. This allows for increased reliability and efficiency of transformer equipment operation. For citation: Khismatullin A.S. Development of a model of a cooling system for a power oil transformer based on sulfur hexafluoride. Bulletin of the Tomsk Polytechnic University. Geo Assets Engineering, 2026, vol. 337, no. 8, pp. 16–23. https://doi.org/10.18799/24131830/2026/8/5058