应用有限元法计算覆冰合成绝缘子电位分布

为研究合成绝缘子的电气特性,应用有限元法计算了具有开域边界的220kV覆冰合成绝缘子的电场和电位分布。通过设置人工截断边界,将开域电场问题转化成有界域电场问题并在人工截断边界上采用渐近边界条件,利用femlab商用软件对覆冰合成绝缘子建模,计算改变冰棱的空气间隙长度及位置后的电场和电位分布,进一步研究冰棱表面水膜对电场和电位分布的影响。研究结果表明,冰棱完全桥接时电场和电位分布变化最大;冰棱在绝缘子伞裙外沿分布的位置不同,对电场和电位分布的影响也不同;水膜的出现使得覆冰合成绝缘子沿面的电场和电位分布进一步发生畸变;与传统瓷、玻璃绝缘子相比,合成绝缘子具有重量轻、强度高、耐污性能高、运行维护方便等特点。

Calculation of Potential Distribution to 220 kV Icing Non-ceramic Insulators by Finete Element Method

Finite element method ( FEM) is applied to the calculation of potential distribution for 220 kV icing non-ceramic insulator surge arrester with open boundary. The open boundary field problem is transformed to the bounded field problem through setting artificially truncating boundary with asymptotic boundary condition. It carries on the model of the icing non-ceramic insulator using the femlab commercial software, and calculates fields electric field and the potential distribution after the change ice position and air gap length, further studies influence of surface water film to the electric field and the potential distribution. It discovers when ice completely bridges joint, the change of electric field and the potential distribution is biggest. The ice is different outside the insulator umbrella skirt along the distributed position. The influence of ice to electric field and the potential distribution is also different. Water film appearance causes the regelation synthesis insulator further of theelectric field and the potential distribution. Icing poses a great threat to safe operation of power system. Compared with traditional ceramic and glass insulators, composite insulators have the advantages of less weight, higher strength, more excellent anti-contaminated characteristic, and easier to be maintained. Consequently, it is widely used by power utilities in many iced areas, non-ceramic insulators are used widely in electric system. So, calculation of electric field and potential distribution for icing non-ceramic insulator is momentous significant to study electric characteristic of non-ceramic insulator.