四川部分变电站涂覆RTV绝缘子的自然积污成分及其对闪络特性的影响

Natural Pollution Component for RTV-coated Insulator in Some Substation of Sichuan Province and Its Effect on Flashover Characteristics

RTV(室温硫化硅橡胶)涂料等有机绝缘材料表面积污往往较瓷和玻璃绝缘表面更为严重,在以四川盆地为代表的潮湿地区,其表面甚至会有生物生长,增大了绝缘子的闪络风险。为此通过调研和取样,研究了四川地区各变电站内涂覆RTV绝缘子表面的自然污秽及其分布状况,利用原子吸收光谱法和阴离子色谱法得到了污秽中可溶性盐的主要成分;并通过显微组织观察、培养和表面性能测试,得到了污层中藻类的种属和生长特性,及其对RTV表面憎水性和电导率的影响;最后通过人工污秽和自然污秽试验,获得了不同污秽成分对RTV绝缘子闪络特性的影响。结果表明,四川电网RTV绝缘子表面自然污层可溶性盐以Ca SO4为主,藻类在RTV表面的分布与污秽分布正相关,并使被覆盖区域的憎水性大大降低,电导率升高;藻类的存在、Na Cl作为可溶性盐都可使闪络电压降低,而污秽的不均匀分布、Ca SO4作为可溶性盐分的RTV绝缘子闪络电压较高。

The contamination deposition on the surface of organic insulation materials like RTV （room temperature vulcanized） silicone rubber is more serious than that on the porcelain and glass insulation surface. Furthermore, the surface of RTV-coating is often covered with bio contamination layer in wet and worm place like Sichuan basin. This phenomenon may increase the potential risk of pollution flashover. Consequently, we analyzed the component and distribution of the natural contamination collected on the surface of RTV-coated insulators in various transformer substations all around Sichuan basin. The main soluble component ofpollntion was obtained by AAS （atomic absorption spectrometry） and IC （ion chromatography）. Moreover, microstructure observation, cell culture, and surface performance test were used to obtain the species and the growth characteristic of algea, and the effect of bio contamination on surface performance of RTV-coating. The results indicate that the main composition of soluble salt is CaSO4, and there is a positive correlation between the distribution of pollution and the intensity of algae, which significantly decreases the hydrophobicity and increases the surface conductivity of the RTV-coating. The growth of algae and NaCl （as the main soluble component of pollution） can decrease the flashover voltage. On the contrary, the non-uniform distribution of pollution layer, CaSO4 as the main soluble component of pollution can increase the ftashover voltage.