高压全膜电力电容器热学数值模拟及实验研究

Numerical Simulation and Experimental Study on High-voltage Full-film Power Capacitor Thermodynamics

在设计高压电容器单元时,为了防止温度过高而引起薄膜电容鼓胀、击穿乃至爆炸等危险情况,有必要对其温升进行计算和校核。针对变电站补偿无功所使用的高压全膜电容器组,根据其几何结构与材料参数,设计一种包括热仿真边界条件的热学仿真模型,使用基于有限元方法的瞬态热仿真软件模块进行求解,得到电容器在热稳定状态下的整体温度云图;同时根据仿真结果,进一步分析3台电力电容器共同工作时的温度场分布;最后通过实验验证,研究对比电容器在额定工况下的内外部温度云图。仿真结果表明:电容器外部温度由头部至尾部呈上升后逐渐下降趋势,离底部约三分之一处温度最高,外壳底部温度略高于顶部;3台电容器同时工作时,外壳最高温度高出单台工作下外壁最高温度1.79℃。仿真与实验结果对比证明了建模方法的有效性。

When designing a high-voltage capacitor unit,it is necessary to calculate and check its temperature rise in order to prevent dangerous situations such as swelling,breakdown and even explosion of the film capacitor when the temperature is too high.Therefore,this paper designs a thermal physical model of the capacitor including thermal simulation boundary conditions for a group of high-voltage full-film capacitors used for reactive power compensation in ordinary substations according to the geometric structure and material parameters.It uses a transient thermal simulation software based on the finite element method for solution and obtains the temperature cloud chart of the capacitor as a whole tends to be set in a thermally stable state.Based on the simulation results,the paper further analyzes the temperature field distribution when three power capacitors work together.Finally,it compares the internal and external temperature cloud charts under the rated working conditions by means of experimental verification.The simulation results show that the external temperature rises from the head to the tail of the capacitor and then gradually decreases,reaching the highest temperature at about one-third of the bottom,and the temperature at the bottom of the case is slightly higher than that at the top.When three capacitors work at the same time,the highest temperature of the case is 1.79°C higher than the maximum temperature of the outer wall under the operation of a single unit.The comparison between the simulation and the experimental results proves the effectiveness of the modeling method.