架空输电线路不均匀染污绝缘子直流闪络特性分析OA

[Objective]A crucial role is played by insulators in providing insulation and mechanical support during the operation of overhead transmission lines.However,in complex and ever-changing natural environments,the surfaces of insulators are highly susceptible to the adhesion of pollutants such as dust and salt,which can result in uneven contamination,seriously alter the electrical performance of insulators,affect their DC flashover characteristics,and increase the risk of flashover accidents on the line,thus causing serious consequences such as power outages,and posing a huge threat to the safe and stable operation of the power system.Therefore,this paper aims to analyze the direct current(DC)flashover characteristics of unevenly contaminated insulators.[Methods]Both the uneven contamination during actual operation by creating an unevenly contaminated insulator model,and the DC flashover process of unevenly contaminated insulators in overhead transmission lines based on electromagnetic field theory were simulated.The two key parameters of non-soluble deposit density(NSDD)and salt deposit density were selected to comprehensively explore the influence of contamination on the flashover characteristics of insulators.Specifically,the content of insoluble contaminants on the insulator surface was reflected by NSDD,while the content of soluble contaminants was reflected by salt deposit density.The adhesion of contaminants on the insulator surface under different contamination levels was simulated by adjusting the wind speed,as the deposition rate and distribution of contaminants on the insulator surface can be affected by wind speed.Additionally,the DC flashover voltage of insulators with different combinations of NSDD and salt deposit density in different wind speed conditions was recorded.[Results]Uneven contamination can cause significant changes to the electric field distribution on the insulator surface,leading to non-uniformity in the originally even electric field.Meanwhile,the too high local electric field strength can increase the possibility of flashover.NSDD formed by non-soluble contaminants can reduce the risk of flashover to a certain extent.This is because although NSDD changes the roughness of the insulator surface,they themselves are non-conductive,thus to some extent hindering the conduction of currents and increasing the flashover voltage.In contrast,soluble contaminants of salt deposit density are prone to form conductive channels in humid environments,thus significantly reducing the insulation performance of insulators and flashover voltage.Analysis was further conducted on the experimental data to verify the accuracy of the analysis results,and the results show that the fitting coefficient is high,indicating sound agreement between the obtained analysis results and the actual situation.[Conclusions]By simulating the influence of wind speed on the contamination situation of the insulator surface,the actual operating environment gets truly reflected,providing new ideas and methods for studying the DC flashover characteristics of unevenly contaminated insulators.Important theoretical basis and technical support are provided by this study for the selection of insulators for overhead transmission lines,the development of anti-contamination measures,and the safe and stable operation of power systems.The incidence of power outages caused by insulator flashover can be reduced and the power supply stability can be improved.