| There are different kinds of contaminants on the insulators in natural environment. These contaminants effect the flashover characteristics of insulators. The domestic and foreign research on the mechanism and characteristics of pollution flashover on the transmission line insulators is relatively mature, but the research on the effects of different contaminants on transmission line insulation has not be carried out systematically yet. Because of its hydrophobicity and hydrophobicity migration, composite insulator is different from porcelain insulator and glass insulator. Composite insulator is of more and more extensive application. Therefore, this paper bases on composite insulator as the research object. Experiments research the AC pollution flashover characteristics of composite insulators in different pollution composition.The main work of this paper is as following:Nine kinds of typical soluble salt contamination components with high content is selected. The pollution flashover voltages of test product insulators are measured with two kinds of composite insulators for sample in accordance with the artificial pollution test method. The AC pollution flashover characteristics of two kinds of composite insulators under different soluble salts are obtained. The AC flashover voltages of composite insulators are different under different soluble salts. The flashover voltage gradients have a negative exponential relationship with SDD. The influence of three pairs of ion on the pollution flashover voltage of composite insulators is compared.The artificial pollution test results are analyzed through the measurement of water solution conductivity converted to the value of 20℃of soluble salts, combined with physical and chemical properties of soluble salt contamination components. It considers that the heat decomposition of ammonium salts is the reason of the corresponding flashover voltage rises and the Ca SO4 corresponding pollution voltage is high because its solubility in water is very small. Therefore, to determine the effect of a pollution component on the pollution flashover voltages of composite insulators can not only be on the basis of the strength of conductive properties of the component or ions.Through the analysis of the solubility of soluble salts in different temperatures and the calculation of p Km values in 30℃, the solubilities of different soluble salts in limited water and the order of solubility of typical salts are obtained. The salts with high solubility correspond to lower pollution flashover voltage in the same ESDD, and those with low solubility correspond to higher pollution flashover voltage.Three kinds of typical insoluble matters with high content is selected. The pollution flashover voltages of test product insulators are measured with two kinds of composite insulators for sample in accordance with the artificial pollution test method. The AC pollution flashover characteristics of two kinds of composite insulators under different insoluble matters are obtained. Through the test and analysis, it considers that the property and type of insoluble matters have effects on the surface hydrophobicity migration characteristics of composite insulators. Therefore, it leads to the difference of the pollution flashover voltage of composite insulators.Anyway, for soluble salt contamination components, the anions mainly decided the pollution flashover characteristics, namely the same anions correspond to the similar pollution flashover characteristics, and different anions correspond to different pollution flashover characteristics. For insoluble matters, the ability to block hydrophobic migration and the ability to stick to the surface of silicone rubber materials are the main factors affecting the pollution flashover characteristics of composite insulators. |
PDF Full Text Request