复合绝缘子导线上缠绕绝缘护套对鸟粪闪络的防护效果分析

Research on Effect of Wrapping Insulation Sheath to Wire on Bird Streamer Flashover on 220 kV Composite Insulator

鸟害故障已成为威胁输电线路安全稳定运行的重要因素之一,其危害程度仅次于雷击和外力破坏,而鸟粪闪络是所有鸟害故障中最典型的故障类型,所占比例最高。笔者提出了一种在复合绝缘子高压侧导线上缠绕绝缘护套用以防范鸟粪闪络的方法,试验给出导线上缠绕绝缘护套后均压环电位降低,有效避免了鸟粪跟均压环之间的放电,使得鸟粪闪络危险区域范围大幅减小,该措施对于防范鸟粪闪络是有效的。此外,以模拟试验平台为研究对象,建立三维仿真模型,计算了绝缘护套不同介电常数、厚度以及不同金具长度等情况下对复合绝缘子的影响,计算结果表明,缠绕绝缘护套使得均压环电位降低,降低了鸟粪闪络的可能性,此外,复合绝缘子沿面电位计电场分布得到改善,有利于其安全运行。

Bird damage has become one of the most important factors endangering the safe operation of transmission lines, which degree of harm is second only to lighting and external forces, while streamer flashover is the most typical type, ranking the first of all bird damage. The paper presents a preventive measure against streamer flashover by wrapping insulation sheath to wire. Tests results show that the potential of equalizing ring decreases after wrapping insulation sheath, which effectively avoid the occurrence of discharge between streamer channel and equalizing ring, as a result, scope of risk area decreases. Besides, the paper also establishes three- dimensional simulation model, calculating the effect of insulation sheath on composite insulator under different value of dielectric constant, thickness of insulation sheath and length of fittings. Results show that wrapping insulation sheath decreases the potential of equalizing ring and decrease the possibility of streamer flashover, besides, the electric field distribution along the surface of the composite insulator is improved, enabling its safe operation.