1000kV级特高压交流线路绝缘子串电位分布计算和均压环设计

特高压交流线路绝缘子串的电位分布极不均匀,这将影响绝缘子和线路的安全运行,如何设计合理的均压环,改善绝缘子串电位分布,具有重要的工程意义。应用有限元法可以对特高压绝缘子串单悬垂串下的电场分布进行三维的数值计算,综合考虑杆塔、导线等因素,针对悬垂串不同的均压环设计尺寸和放置位置分布进行对比计算。对均压环的优化设计表明,均压环管径取120mm,环体距绝缘子串中心距离取500mm,布置位置为屏蔽3片绝缘子时,均压效果相对较好。计算结果表明,增加均压环后各个串型的电场分布明显改善,单片绝缘子最大承受电压为4.7%。

Electric field distribution calculation and grading ring design of insulators string for 1 000 kV UHVAC lines

For UHVAC transmission lines, the field distribution of insulator strings is extremely non-uniform, which will affect the operation safety of insulators and lines. It has important significance to improve the electric field distribution through well grading ring design. The electric field distribution of suspension insulator strings for 1 000 kV UHVAC lines was calculated by means of FEM method. The tower and the conductor were also taken into account. Different design dimensions and position of grading rings corresponding to suspension I string was calculated. The optimization of grading ring indicates that the grading effect is preferable when pipe diameter equals to 120 mm, the distance of ring plane to string center equals to 500 mm and the ring screens 3 insulators. The calculation results of insulator string added ring indicate that the electric field distributions of various insulator strings of suspension types are clearly improved and the maximal withstand voltage of single insulator is less than 4.7 percent.