1000kV交流复合绝缘子均压环参数设计

Design of Grading Rings for 1000kV AC Composite Insulator

为了将1000kV交流特高压输电线路复合绝缘子沿面电场分布控制在合理的范围内,根据复合绝缘子的特点,采用场域分解的方法将三维无界场域分解成有界子区域,选择使用有限元法进行1000kV交流输电线路复合绝缘子串沿面电位、电场分布计算及均压环参数优化设计。应用ANSOFT软件建立1000kV交流线路带杆塔、导线的全三维模型,研究了均压环的管径、环径和抬高距离对绝缘子电场分布影响的规律,从控制电场强度的角度出发得到了均压环结构参数的配置方案。三维计算结果表明,安装了均压环后,复合绝缘子护套、金具、均压环表面最大电场强度均可以满足要求,绝缘子沿面电位分布的均匀性也得到了提高。金具可见电晕和无线电干扰试验的结果表明,高压端金具和均压环的起晕电压、无线电干扰均符合国家标准要求。

The electric field strength along the composite insulators should be restricted to maintain at a reasonable range. We adopted the finite element method to calculate the electric field and potential distribution along composite insulators as well as design the grading rings for the 1000 kV UHVAC transmission lines by the domain decomposition method according to the features of the composite insulator. The three-dimensional （3D） model of 1000 kV transmission lines with tower configuration and conductors were established by using the ANSOFT software. The effect of the corona ring for improving the electric field distribution on the composite insulator was investigated by changing the parameters of the corona ring, such as the ring radius, radius of the ring tube, and the position of the ring in its vertical plane. The approved parameters of the corona ring were gained in terms of controlling the electric field to be acceptable, and the optimized parameters of the grading ring were verified in the 3D model. The results indicate that the maximum electric field around the sheath, metal fitting and the grading ring are controlled to be satisfactory, and the potential distribution along the insulator becomes more uniform. The corona and RIV tests show the corona inception voltage and radio interference voltage of the fittings and corona rings can well meet the national standards.