| During pollution flashover, wet flashover, ice flashover, lightning flash over and operation flashover, pollution flashover is the most serious to the Power Systems. The scholars, who research into pollution flashover, try to analyze the critical condition of insulator flashover via local arc in series with resistance of remaining pollution layer. So resistance of remaining pollution layer is unavoidable. But at present, usually disk model, rectangle model and rectangle model are used to equal to the real insulator. This is very different from the actual situation. So the study of the worth and analytic expression of resistance of remaining pollution layer of the true insulator is very important to the science and engineering.Three types insulators, LXY-160,FC-16P and FC-160D were researched and expanded to flat plate models, in which length is corresponding to insulator's leakage distance and width corresponding to circumference. Baced on this model, neglecting some stochastic states of partial arc, two arcs, which lead to flashover, burn at cap and pin at the same time. While critical state, these two arcs are still exist. Based on this phenomenon, the double arc pollution flashover model was derived. Program is programmed to calculate critical length of arc on top and button, critical leakage current and critical flashover voltage. In order to fix calculation Results, arc fluttering factor was brought in.At the same time, flat plate model was made and put to artificial pollution test. Process of pollution flashover was shot, the expressions of form factor of remaining pollution layer were derived, while critical arcs are at different locations. Resistance of remaining pollution layer was calculated. Using critical flashover voltage and leakage current, resistance of remaining pollution layer was calculated to verify.In order to study composite insulator, rectangular silicone rubber plate was used in this paper. The width and thickness of the water band on different hydrophobic level were measured and the resistance of the water band is calculated. As well, using test data, resistance of the water band was calculated to verify.Through theoretical calculations and experimental study, following conclusions were obtained in this paper:Model calculations show that: there is no relationship between critical length of arc and SDD. Ratio of critical length of arc to leakage distance of the 3 flat plate models is 0.54 or so. With the increasing of the SDD, resistance of remaining pollution layer is gradually reducing. With the increase of the T/B, resistance of remaining pollution layer is gradually increasing.According to pollution flashover test: with the increasing of the T/B, flat plate model's critical length of arc is gradually reducing. Ratio of critical length of arc to leakage distance of the 3 flat plate models decreases from 0.55 to 0.41. But, critical length of arc on top surface is gradually increasing. Correction factor P, nonuniform pollution to resistance of remaining pollution layer, has a good fitting. Related coefficient of 3 flat plate are all more than 0.99.Compared with resistance of remaining pollution layer calculated by experimental data, goodness of fit is very well. The study in resistance of remaining pollution layer is feasible.During the pollution flashover of composite insulator, with the decline of the hydrophobic level, the thickness of the water band is gradually reducing and the width of the water band is gradually increasing. When HC5, the width of the water band increases substantially. With the decline of the hydrophobic level and the increase in conductivity, the resistance of the water band gradually decreases. When HC5, the resistance decreases substantially.Compared with resistance of water band calculated by experimental data, there is certain difference, especially while HC1 and HC2. The resistance of water band in this paper reflects the true situation to some extent. |
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