为了研究特高压直流绝缘子的自然带电积污特性,进行了全电压全尺寸特高压直流绝缘子积污特性试验。测定了绝缘子的等值盐密(ESDD)、等值灰密(NSDD),分析了不同材质(复合硅橡胶、玻璃、瓷)的绝缘子串,不同串型(I悬垂,V悬垂,耐张)的绝缘子串,不同伞形结构(复合伞裙、钟罩、三伞、瓷长棒)的绝缘子串,以及绝缘子伞裙上下表面和沿绝缘子串不同位置(高压侧、地侧、中间)的积污状况。初步结果表明:不同材质绝缘子串中瓷绝缘子积污最轻;不同串型的绝缘子串中耐张串积污最轻;不同伞形结构绝缘子串中瓷长棒绝缘子是最小积污伞型;伞裙上下表面污秽状况差异巨大,绝缘子杆塔侧积污最重。研究结果可为我国高海拔地区(特别是昆明地区)特高压直流输电工程的外绝缘提供重要的参考。
To obtain the natural contamination deposition characteristics of UHVDC insulators,we tested contamination deposition of full-scale insulators,in which the equivalent salt deposit density(ESDD) and the non-soluble deposit density(NSDD) were measured.A series of comparisons in ESDD and NSDD were performed based on tests on insulator-strings of different materials(glass,porcelain and composites),different string structures(I-shaped suspension type,V-shaped suspension type,and tension type),different shed shapes(composite insulators sheds,porcelain long rod,bell shaped disc suspension,and three-shed type porcelain),and different positions along the insulator-strings(the both ends and the middle of insulator).Preliminary results are obtained from the tests: the porcelain insulator has relatively lighter pollution than other materials;the tension insulator has a much lighter pollution than other structures;the porcelain long rod insulator shows better and has a lighter pollution than that on other shed shapes;and the earth side of the insulator has the most serious pollution in test.This work can provide some important references for the external insulation of UHVDC transmission projects in China high altitudes areas,especially in Kunming.