雾霾天气对输变电设备外绝缘的影响

Influences of Fog-Haze on External Insulation of Transmission and Distribution Equipments

从输变电设备防污闪角度讲,雾霾与传统的湿沉降、污(脏)雾是同一概念。雾霾对输变电设备外绝缘影响的研究,主要包括雾霾的理化特征、雾霾对绝缘子表面污秽度的影响、雾霾的模拟及其对绝缘子污闪电压的影响等内容。文章重点介绍了20世纪90年代以来北京、上海两地开展的试验研究工作:大气污染易演变成霾与雾霾天气,导致输变电设备外绝缘表面湿沉降的增加。雾霾脏污程度可用雾水电导率表征,雾霾的持续作用可使绝缘子表面污秽度有限增大,绝缘子污闪电压有所降低。近年来,国网公司系统坚持"绝缘到位,留有裕度"的防污闪方针,成功地抵御了雾霾天气对输变电设备的侵袭,遏制了大面积污闪事故的发生,线路污闪跳闸率降至历史最低水平。

In the viewpoint of preventing pollution flashover occurred on transmission and distribution equipments,the fog-haze is of the same concept as the traditional concept for wet deposition and dust fog.The research on the influences of fog-haze on external insulation of transmission and distribution equipments mainly includes the physical and chemical features of the fog-haze,the influence of the fog-haze on contamination level of insulator surface,the simulation of the fog-haze and its influence on pollution flashover voltage of insulators.The achievements of experimental research on the fog-haze performed in Shanghai and Beijing since 1990s are emphatically presented： atmospheric pollution easily evolves into the haze or the fog-haze weather,and it makes the increase of wet deposition on external insulation surfaces of transmission and distribution equipments;the smudgy degree caused by fog-haze can be characterized by fog conductivity;the sustained action of fog-haze makes the degree of contamination on insulator surfaces limitedly increased,so the pollution flashover voltage of insulators is decreased to some extent.In recent years,power grids belonging to State Grid Corporation of China persist in the anti-pollution flashover policy of ＂putting the insulation coordination level in its place and reserving a certain margin＂,as a result the encroachment on transmission and distribution equipments due to fog-haze whether is successfully resisted and the occurrence of large-area pollution flashover accidents is suppressed,thus the trip-out rate of transmission lines caused by pollution flashover has reduced to the historically lowest level.