RTV涂层和增爬裙对绝缘子电场分布的影响

为解变电站支柱绝缘子表面电场分布及RTV涂料、增爬裙的影响,用有限元法计算了洁净条件下支柱绝缘子的电场和电势分布规律,提出了模型建立的三原则——根据轴对称性简化模型;采用环形区域作为无限远求解区域;不剖分绝缘子的金属附件。运用上述原则算出RTV涂层绝缘子和增爬裙绝缘子电场分布,分析了RTV涂层绝缘子电场强度稍大的原因、涂层厚度对电场强度的影响及涂层内外部电场强度的关系。研究发现,RTV涂层绝缘子和增爬裙绝缘子表面电场分布的特点相似,绝缘子沿面电场强度与材料属性和结构参数有关。计算表明,0.3mm为涂层厚度的最佳参考值,这与实际情况相符。

Effects of RTV Coating and Creepage Extenders on Electric-field Distribution Along Post Insnlator

The electric-field and potential distribution along a post insulator under dry and clean conditions are calculated through the Finite Element Method(FEM),and three principles about model building are presented.In the process of solid modeling,the post insulator is simplified to a 1/2 area model because of its axial symmetry,and an annular area is innovatively presented to represent the field at infinity.When area meshing,the metallic fittings of the insulator are omitted.The principles discussed above are applied to the calculation,the characteristics of electric-field distribution along RTV coated insulator are reported and compared with those of insulator installed creepage extenders,and the reason about a little stronger electric-field intensity of RTV coated insulator is also analyzed.Furthermore,the effects of coating thickness on electric-field intensity are discussed,and the electric-field intensity inside and outside coating is also investigated.It is concluded that the characteristics of electric-field distribution along RTV coated insulator are similar with those of insulator installed creepage extenders,the electric-field intensity is mainly relevant to material properties and structure parameters,and the relation between the coating thickness and electric-field intensity is nonlinear.From numerical simulation,it seems that the most suitable coating thickness is 0.3mm which is consistent with practical application,and the results can be referred in substation when anti-pollution measures are taken.