基于混合法的油浸式变压器二维瞬态温度场仿真

温升是影响油浸式变压器正常运行的重要因素,为了得到变压器的温度场分布,提出一种基于混合方法的多物理场计算方法。对于油浸式变压器流体场和温度场的强耦合问题,混合方法考虑了温度对媒质物性参数的影响,采用迎风有限体积法和迎风有限元法依次计算流体场和温度场,即流体场和温度场依次循环求解,最终得到油浸式变压器启动过程瞬态温度场和稳态温度场。为了验证文中算法的有效性,采用换流变压器二维简化模型,分别采用文中方法和多物理场仿真软件Comsol计算了常温下的稳态温度场,计算结果验证了混合方法的准确性和有效性。在验证文中算法有效性的基础上,利用该方法分析了换流变压器常温环境下启动过程的瞬态温度场分布,分析结果可为工程提供参考。

2-D Transient Temperature Field Simulation of Oil-immersed Transformer Based on Hybrid Method

The temperature rise of oil-immersed power transformer is a vital factor that affects its performance. In this paper,a multi-physical field calculation method based on hybrid method is presented for obtaining the temperature distribution in the power transformer. In view of the strong coupling between thermal and fluid field, the influence of the temperature on the physical parameters of the material is considered by the proposed hybrid method. The velocity distribution is calculated firstly by solving the governing equation of fluid field used the upwind finite volume method. Then, the upwind finite element method is used to obtain the temperature distribution of thermal field. The fluid and thermal field are solved iteratively, and finally, the transient and the steady-state temperature field of the transformer are obtained during its starting period. To verify the validity of the proposed method, a two-dimensional simplified model of converter transformer has been adopted. The proposed multi-physical field method is applied to calculate the steady-state temperature distribution of converter transformer under ambient temperature, and the result of the proposed method is compared with software Comosol. It shows that the thermal distribution computed by the proposed method is in very good agreement with the results calculated by the commercial software Comosol,which proves the accuracy and validity of the proposed method. Based on the validity of the proposed algorithm, the transient temperature distribution of converter transformer during its starting period is analyzed under ambient temperature. The analysis results can be provided as references for engineering practice.