The Effect Of Contamination Composition On AC Flashover Characteristics Of Insulators

The Insulator contamination flashover is one of the main problems of power grid safety, though it is researched extensively by domestic and foreign scholars for a long term, the varied natural contamination compositions of the polluted insulation have different effects on the pollution flashover characteristic, there is still a certain gap between the artificial pollution flashover test by the single contamination component method and the actual situation. Therefore, the geographical condition should be considerated sufficiently so that the influence rules of chemical components of contamination on the flashover voltage can be researched comprehensively by a series of quantitative analysis.On the basis of summarizing the domestic and foreign research results, the ion chromatograph analysis method is adopted and the ion composition distribution of natural contamination is measured precisely, seven kinds of soluble salts and three insoluble substances are researched to simulate the influence of different impurity composition on porcelain and glass insulators pollution flashover characteristics. Through the research above, the main results are:①The ion chromatography analysis method and the test method measuring the ion composition of natural accumulated contamination composition and mass concentration of each ion composition are put forward, the measurement errors of which are all within 5.00%, meeting the requirement of the ion composition measurement research of the power external insulator natural contamination.②The results of the test indicate that, in the same component content, glass insulator pollution flashover voltage is higher than that of porcelain insulator, the influence of different component of pollution of glass insulator and porcelain insulator is basically the same.③The artificial pollution flashover tests using different soluble salts to simulate the polluted porcelain and glass insulators show that, in terms of soluble substances, there is little difference between the flashover voltage of Na Cl and that of other monovalent ions contamination composition, but the flashover voltage of divalent ions contamination composition is higher than that of Na Cl, which is mainly related to varied water solubility and ionization degree of different kinds of salts, thus their contribution values to the effective conductivity are different.④The effect of insoluble Si O2, Al2O3,Fe2O3 on the flashover voltage is different, in the same NSDD, with the decline of the proportion of Si O2, Al2O3 and Fe2O3 increased, the pollution flashover voltage decreased gradually. The main reason of these is the water absorption characteristics of insoluble and the high temperature thermal decomposition of ionic crystals.