广东地区老化导线湿润环境下交流电晕特性

Corona Characteristics of AC Aged Conductor in Guangdong Area Under Moist Condition

导线电晕特性与导线表面状态紧密相连,长期老化后导线表面状态较新导线变化明显,更容易产生电晕。自然界中由于小雨、凝露等天气影响导致的导线表面湿润环境对电晕的产生和发展有显著影响,因此针对广东地区多组交流线路运行多年后的老化导线在湿润环境下的电晕特性,利用电晕笼进行了试验研究。通过紫外成像仪记录导线放电过程,并根据对应电晕点不同电压下光子计数率,采用切线法计算得到对应电晕起始电压,同时对老化导线的可听噪声和无线电干扰水平进行记录,并与同型号新导线进行对比。结果表明：在水分影响下导线表面的电晕放电更容易形成,且全线放电强度有所增强,湿润环境下老化后导线的电晕起始电压较干燥环境下老化导线和同型号新导线下降4%～9%和10%～14%;老化导线湿润环境下可听噪声水平较自身干燥环境下增长5%～10%,无线电干扰水平也有明显增加。

The corona characteristics are closely related to the surface condition of a conductor. Especially since the aged conductors have so different surface conditions from the new ones, they generate corona more easily. Plus, the moist condition on conductor surfaces caused by light rain and condensation weather significantly influences the corona＇s generation and progress. Therefore, we investigated the corona characteristics of several aged conductors samples taken from the AC transmission lines in Guangdong, China under moist condition through experiments in a corona cage. We detected the corona processes using an ultraviolet imager, and noted the photon counting rate to calculate the inception voltage with the tangent method. In the meantime, the audible noise and the radio interference level were also recorded. All the results were compared to their counterparts of the same-type new conductors. The results show that, for an aged conductor under the moist condition, the corona discharge generates easily on the conductor surfaces with higher intensity along the whole line, and its inception voltage is lower than that of the aged conductor and the new ones under dry condition by about 4%～9% and 10%～14%, respectively. Plus, compared with those under dry condition, the aged conductors under moist condition have about 5%～10% higher audible noise levels, and their radio interference levels are also clearly higher.