Development Of An Asymmetric Gap Lightning Protection Insulator

The operation reliability of 10 kV overhead distribution lines,which are main distribution equipment for medium voltage distribution network in power systems,would directly affects the reliability of the power supply of power systems.Previous observation and operating experience show that lightning is the main reason for the failure occurring on the 10 kV overhead distribution lines.Due to the long path for 10 kV overhead lines,as well as the lines are usually located at the open area,the 10 kV distribution lines are very likely to suffer lightning strokes,resulting in the line break,tripping,and so on.In order to solve these problems,the lightning protection insulators for 10 kV overhead distribution lines are developed.To some extent,the application of lightning protection insulators could reduce the failure on 10 kV overhead distribution lines.However,the insulators also have some deficiencies,which limit their application.In order to further improve the performance of 10 kV lightning protection insulators and reduce the lightning stroke tripping rate,the mechanism of lightning stroke tripping and protection methods of lightning stroke are analyzed in this paper.Based on the numerous investigation of lightning stroke tripping accidents in recent years,the application situation and effects of existing PSL-12/4 type lightning protection insulators are analyzed.Considering the problems of the PSL-12/4 type insulators,suggestions and measurements are proposed to improve the performance of PSL-12/4 type insulators in this paper.Meanwhile,a new kind of lightning protection measure with asymmetrical gap is proposed,and the asymmetrical gap lightning protection insulator is developed.The parameters for the asymmetrical air gap structure and distance,as well as the structure of supporting umbrella skirt,are designed and selected.In addition,the prototype of such asymmetrical gap lightning protection insulator is developed,and the projects for test run are put forward.The experimental results of type test show that the functional indicators of the asymmetrical gap lightning protection insulator accord with the standard requirements.The field test run for prototype also shows in good condition for the asymmetrical gap lightning protection insulator.The statistics of the field test run show that the 10 kV distribution lines never suffer the tripping and breakage after the installation of the asymmetrical gap lightning protection insulators.The results of theoretical analysis and field test run show that the proposed asymmetrical gap lightning protection insulator could prevent the lightning stroke breakage of the 10 kV distribution lines,and also could prevent the tripping accident.In addition,the asymmetrical gap lightning protection insulators have lower cost and higher reliability than previous lightning protection insulators,which are suitable for large-scale application.