高海拔地区玻璃绝缘子的直流污闪特性

DC Flashover Characteristics of Glass Insulator in High Altitude Area

为了解决特高压直流输电线路中的外绝缘问题,清华大学深圳研究生院和云南省电力试验研究院合作,通过对两种大吨位玻璃绝缘子在不同盐密、不同灰密、不同染污情况和不同悬挂方式下进行直流污闪特性试验,对其污闪特性作了深入研究。试验表明,玻璃绝缘子和瓷绝缘子直流污闪特性相似;高海拔条件下,由于飘弧现象严重,爬电距离并不能得到有效的利用,故不是影响污闪特性的唯一重要因素;结构高度和绝缘子形状结构在很大程度上可影响飘弧和电弧桥接,因而对污闪特性的影响很大,在一定程度上大于爬电距离对污闪特性的影响;同时分析了非均匀染污情况和不同悬挂方式下的污闪特性及其差异原因。

In order to solve external insulation problems in the Ultra High Voltage DC transmission lines and study the flashover characteristics of porcelain, glass and composite insulators, a series of experiments have been conducted by the Graduate School at Shenzhen, Tsinghua University in high altitude area （ 1 970 m）. As part of this series, DC flashover characteristics of two types of glass insulators under different ESDD, NSDD, contamination patterns and suspension patterns were studied in this paper. The tests were carried out at YunNan Electric Power Research Institution, using a high-speed camera recording the flashover arc and an instrument developed by Tsinghua University to record the leakage current in the tests. The test results indicate that the glass insulator has a similar DC flashover performance as that of the porcelain insulator. The results also demonstrate that the arc levitation phenomena are much more serious in high altitude area, resulting in the creepage distance could not be utilized effectively. The creepage distance, therefore, is not the only important factor influence the flashover performance. However, the insulator＇s shape and configuration height have a great impact on the arc levitation and bridgeover phenomena, which have a larger influence on DC flashover performance in high altitude area than that of the creepage distance. At the same time, DC flashover performances of glass insulator under different contamination patterns and suspension patterns are also studied and the reason is analyzed in this paper.