500kV棒形悬式复合绝缘子芯棒脆断的预防措施

对500kV复合绝缘子芯棒脆断事故的发生原因进行了分析,指出芯棒断裂是由于绝缘子电压分布严重不均及均压环设计、安装不规范引起导线端电场畸变所致。通过对原线路双联悬垂复合绝缘子下垂式线夹挂点进行"八"字形改造;利用下垂式线夹缩短的距离在导线侧增挂玻璃绝缘子;新建线路采用特制复合绝缘子与玻璃绝缘子组合方式,使复合绝缘子均压环,接头连接处远离高压端,改善了复合绝缘子的电场分布,降低了复合绝缘子导线端承受的电压,消除了畸变电场,避免了棒形悬式复合绝缘子芯棒脆断,取得了良好的效果。

Precaution for Composite Rod Insulator of 500kV Against Rod Brittle Fracture

Analysis has been made on cause of core brittle fracture of composite insulator of 500kV.It is pointed out that the core brittle fracture is caused by extremely uneven voltage distribution along the insulator string and irregular designing and mounting of grading ring which leads to deformation of electric field on conductor end of insulator.It is proposed to replace the suspension clamp by a "八"shape joint strap and installing a glass insulator at this space or introducing a special composite insulator-glass insulator combination to separate the grading ring and insulator joint far away from high voltage end,thus avoiding the brittle fracture of composite insulator.Practice shows a satisfactory effect.