220kV三凤线N38塔地段污情分析

针对外绝缘配置的适应性进行了探讨，测定了产生严重串弧的绝缘子的等值附盐密度，结合在线监测到的泄漏电流、环境变化情况以及绝缘子表面积污不均匀分布试验，分析了等值附盐密度在划分污秽等级时的局限性，认为酸雾及沿海盐污等动态污秽虽然不以沉积方式滞留在绝缘子表面，但会加速外绝缘的降低；同时证实了环境相同、爬电距离和高度相等的情况下，瓷质双伞绝缘子的耐污水平优于钟罩玻璃绝缘子，涉及到有效利用系数的问题。为此，推荐使用采集到的相对湿度一泄漏电流曲线监视外绝缘的变化，用以指导外绝缘配置及状态管理。

Investigation into Pollution of Tower N38 Section on 220 kV Sanfeng Line

The adaptability of external insulation disposition is dealt with, and the equivalent salt deposit density （ESDD） of insulator producing grave series arc is measured. Combined with the on-line monitoring data of leakage current, environmental changes and inhomogenous distribution testing of insulator surface pollution, the limitation of ESDD in pollution classification is analyzed. It is held that dynamic contaminations such as acid fog and coastal salt pollution may accelerate the deterioration of external insulation, though they do not deposit on the surface of insulator. It is also proved that with identical surroundings, creepage distance and height, the antipollution ability of porcelain twin-shed insulator is better than that of bell glass insulator, as the effective utilization factor is involved. The acquired curve of relative humidity to leakage current is suggested for monitoring the changes of external insulation, so as to guide the external insulation disposition and state management.