±800kV线路直流复合绝缘子均压环结构研究

Optimization of Corona Ring Design for ±800 kV UHV DC Transmission Lines

为控制复合绝缘子表面电场,用有限元法建立的输电线路直流复合绝缘子三维电场计算模型研究了影响复合绝缘子表面电位和电场分布的因素及均压环的半径、管半径和抬高距离对绝缘子电场分布影响的规律,从控制电场角度得出了合理的均压环结构参数。针对特高压复合绝缘子的电场分布特点提出的一种应用于±800kV直流复合绝缘子的大小双均压环结构参数的计算结果表明,双均压环可更好地改善绝缘子端部电场分布。该研究结果可供设计±800kV直流特高压线路的外绝缘参考。

Based on the finite element method, a three-dimensional electric field model, considering the effect of transmission lines, tower and ground, is found to calculate the potential distribution and electrical field distribution along the composite insulator on ±800 kV UHV DC transmission lines. The effect of the corona ring for improving the electric field distribution on the composite insulator is studied by changing the parameters of the corona ring, and the proper parameters of the ring radius, radius of the ring tube, and the position of the ring in its vertical plane are investigated in consideration of controlling electric field that cannot exceed the corona inception level. To improve the high electric field on the two ends of composite insulator on ±800 kV UHV DC transmission line, the paper presents a new ring configuration consisting of a big ring and a small ring on each end of the insulator. The position of the small ring is between the ordinary big ring and the end fitting of the insulator, and it could improve the high electric field near the end of the insulator. An optimization size of the rings is calculated based on a mass of computations and studies. It also offers some help for external insulation design of the UHV transmission lines.