大型水轮发电机定子线棒绝缘参数对线棒槽部表面电位分布及电场分布的影响

应用有限元分析软件COMSOL建立了定子线棒槽部模型,仿真分析了绝缘材料参数和厚度对槽部线棒表面电位分布及电场分布的影响规律。结果表明:槽部无气隙的情况下,线棒表面电位最大值出现在防晕层上、下表面的中间位置,电场最大值位于主绝缘角落内侧;对线棒表面电位有影响的是主绝缘相对介电常数、防晕层电阻率和主绝缘厚度,在常见的范围内,主绝缘电阻率和相对介电常数基本不影响槽部电场分布;防晕层表面最大电位与主绝缘相对介电常数呈正相关,与主绝缘厚度呈负相关,与防晕层电阻率的对数值呈正相关且后期影响减弱;主绝缘相对介电常数、防晕层电阻率和主绝缘厚度对槽部最大电位具有综合影响,可通过数值分析得到三元三次多项式的回归模型。

Influence of Insulation Parameters on Surface Potential and Electric Field Distribution on Slot Part of Large Hydro-generator Stator Bar

A slot part model of stator bar was established by finite element analysis software COMSOL,and the influence law of parameters and thickness of insulating material on the surface potential and electric field distribution of winding bar slot part was simulated and analyzed. The results show that when there is no air gap in the slot part, the maximum surface potential of winding bar is located at the midpoint of the upper and lower surface of anti-corona coating, and the maximum electric field is located inside the main insulation corner. The relative dielectric constant and thickness of the main insulation and the resistivity of the anti-corona coating have influence on the surface potential of wingding bar, while the resistivity and relative dielectric constant of main insulation in common range have little effect on the distribution of electric field. The maximum surface potential of anti-corona coating is positively correlated with the relative dielectric constant of the main insulation, negatively correlated with the thickness of the main insulation, and positively correlated with the logarithmic value of resistivity of anti-corona coating and the effect is weakened in later period. These three material parameters have comprehensive effects on the maximum potential of slot part, and the regression model of ternary cubic polynomial can be obtained by numerical analysis.