特高压带电作业绝缘工具操作冲击放电特性及试验电极优化

目前检测机构对特高压带电作业绝缘工具开展操作冲击耐压试验时，电极布置仍沿用低电压等级标准，但试验电压和放电间距大大增加，经常出现绝缘工具间、试验电极对大地或周边构架等非试验通道放电的情况。开展了典型作业工况及试验工况下带电作业用绝缘工具标准波头操作冲击放电特性试验，并对试验工况下放电路径进行统计，提出了采用8分裂U型模拟导线的优化方案，并进行了试验验证，研究结果表明：采用8分裂U型模拟导线可显著降低非试验通道分散放电的概率；对多个试品同时进行试验时，由于存在空气间隙拉弧，试品挂接的水平间距建议不小于5 m；试验电极改进后绝缘杆6.3 m放电电压为2 417 kV，较标准电极增加6.9%，较典型作业工况下最低放电电压增加32.1%，进行绝缘工具耐压试验时建议根据作业工况的耐压要求对试验电压进行修正。

Switching Impulse Test of UHV Live Working Insulating Tool and Experimental Electrode Optimization

At present, the electrode arrangement still follows the low voltage level standard when the UHV live-working insulating tools are tested for operation impulse withstand voltage. However, the test voltage and the discharge interval are greatly increased, and discharge often occurs in the non-test channels such as the interval between insulating tools, and the interval between test electrode and the earth or surrounding frames. For this reason, standard wave switching impulse tests are conducted on the insulating tools used for live-working under typical working conditions and test conditions, and the discharge paths under test conditions are counted. An optimization scheme of using 8-bundle U-shaped analog wires is proposed, and corresponding tests are conducted for verification. The results show that using the 8-bundle U-shaped analog wires can significantly reduce the probability of dispersive discharge in non-test channels. The horizontal spacing of the test specimens shall not be less than 5m due to the presence of air gap arcing. After the test electrode is improved, the discharge voltage of the 6.3-m-long insulating rod is 2417 kV, which is 6.9% higher than that of the standard electrode, 32.1% higher than the minimum discharge voltage under typical working conditions. When the insulating tools are tested for withstand voltage, it is recommended to correct the test voltage according to the withstand voltage requirements of the working conditions.