Numerical Calculation Method and Verification of Three-Dimensional Thermal-Fluid Coupling Field for High-Voltage Bushings
Chu Zhilin1, Wang Qingyu1, Liu Zexi1, Liu Peng1, Han Xiaodong2
1. State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong University Xi'an 710049 China; 2. Xi'an XD High Voltage Bushing Co. Ltd Xi'an 710077 China;
Abstract：With the development of high voltage direct current (HVDC) transmission towards higher voltage levels, the current load of primary equipment such as converter transformer valve-side bushings continues to increase. Dry-type bushings have weak heat dissipation capacity due to their epoxy cores, making them prone to overheating faults during long-term operation under high loads. However, the accurate simulation of the internal thermal-fluid field distribution of bushings has long relied on foreign commercial software. To achieve independent and controllable thermal-fluid coupling simulation for converter transformer valve-side bushings, this study proposed a numerical calculation method for the three-dimensional thermal-fluid coupling field of high-voltage bushings. This method comprehensively considered three heat transfer processes inside the bushing: heat conduction, heat convection, and thermal radiation. For heat convection calculation, the Boussinesq assumption was adopted for simplification, and the view factor was introduced to describe the transfer process of radiant energy. The finite volume method was used to discretize the momentum conservation equation and energy conservation equation in 3D space, thereby constructing a bidirectional coupling model of the thermal field and fluid field. A pressure correction algorithm for iterative solution of incompressible flow problems was developed based on the mass conservation equation and momentum interpolation equation. A transient process was introduced to improve the convergence of iterative solutions, and a loosely coupled conjugate heat transfer technique was applied in the transient process. Different time steps were adopted for different structures, ensuring computational accuracy while maintaining efficient calculation progress. A non-orthogonal correction method for calculating thermal-fluid diffusion in 3D unstructured grids was proposed. To avoid numerical divergence caused by excessive correction of the correction term in high-skewness grids, a non-orthogonal correction factor was added to limit the correction amplitude, forming a complete numerical calculation method for 3D thermal-fluid coupling field distribution. Temperature field simulations of ±400 kV and ±800 kV converter transformer valve-side bushings were conducted. When the non-orthogonal correction factor was set to 0.5, the simulation results were basically consistent with those from commercial software, and the maximum errors compared with temperature rise test results are 6.95% and 5.89% for the two types of bushings, respectively. When the correction factor was set to 1, the maximum errors compared with test results decreased to 6.82% and 5.09%, but the risk of non-convergent calculation results increased. Test results verify the reliability of the proposed method in engineering applications. This research provides a flexible and controllable solution for analyzing the internal temperature field distribution of bushings and promotes the development of domestic thermal-fluid coupling simulation software.
楚智霖, 王青于, 刘则希, 刘鹏, 韩晓东. 高压套管三维热-流耦合场数值计算方法与验证[J]. 电工技术学报, 2026, 41(15): 5237-5248.
Chu Zhilin, Wang Qingyu, Liu Zexi, Liu Peng, Han Xiaodong. Numerical Calculation Method and Verification of Three-Dimensional Thermal-Fluid Coupling Field for High-Voltage Bushings. Transactions of China Electrotechnical Society, 2026, 41(15): 5237-5248.
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2026, Vol. 41 
