复合绝缘子无溢流覆冰增长数值模拟及自然覆冰试验验证

Numerical Simulation and Natural Icing Experimental Verification on Non-overflow and Wet Growth on Composite Insulators

绝缘子覆冰对电力系统的安全可靠运行构成了严重威胁。目前,主要从试验角度定性解释伞裙结构对绝缘子覆冰形态、覆冰量的影响,少有基于覆冰增长机理的冰形数值模拟研究。因此以FXBW-35/70为研究对象,基于流体力学和热力学原理,计算分析了绝缘子表面冻结系数和对流换热系数的变化规律,建立了绝缘子无溢流覆冰增长三维数值模型,并进行了自然覆冰试验验证。结果表明,冻结系数随着温度、水滴直径和液态水含量的升高而降低;对流换热系数随着风速的增大而增大。绝缘子无溢流覆冰增长方向与位置有关,杆径覆冰主要沿径向增长,而伞裙边缘覆冰沿径向和轴向2个方向增长。模型计算得到的绝缘子覆冰特征参数与试验的误差均在15%以内,验证了模型的有效性。

Insulator icing threatens the safe and reliable operation of power systems.The influence of shed structure on ice shape and amount of insulator icing is mainly explained qualitatively from the experimental point of view,and few numerical simulation studies of ice shape based on the icing growth mechanism are available.Therefore,we used FXBW-35/70 to calculate and analyze the variation law of insulator surface freezing coefficient and convective heat transfer coefficient based on the principles of fluid mechanics and thermodynamics,established a 3-D numerical calculation model of insulator without overflow icing,and verified the model by natural icing experience.The results show that the freezing coefficient decreases with the increase of temperature,water droplet diameter,and liquid water content;the convective heat transfer coefficient increases with the increase of wind speed.The growth direction of insulator non-overflow icing is location-dependent,the rod diameter icing grows mainly along the radial direction,and the shed icing grows in both radial and axial directions.The calculated insulator icing characteristics are within 15%of the experimental errors,which verifies the validity of the model.