Study On The Commonality Of Technology For Comples Lightning Protection Of Mountainous Area Power Transmisson Lines Based On Gas Arc Extinguishing Method

The year 2020 is the closing year of China s 13 Five-Year Plan,and the development of China s electricity system has been gaining momentum over the past five years.At the same time,the hazards of lightning activities are transmitted from the transmission lines to the power terminals,the formation of the butterfly effect is also increasing,threatening all aspects of national economic life.Due to the inefficiency of the transmission and control system,the lightning strike trip rate remains high,the transmission line lightning protection is facing multiple challenges of high incidence of lightning damage,seriousness of loss,urgency and difficulty of lightning protection.In this paper,based on the gas arc extinguishing lightning protection method,an applied study is conducted on the mountain power transmission lines under complex lightning conditions,and a common protection method for gas arc extinguishing lightning protection devices under different voltage levels is proposed.Firstly,an analysis of the shortcomings of the existing blocking and guided lightning protection methods is presented,and then the gas arc extinguishing method is introduced,which is a new type of lightning protection method that integrates impact-evacuation,rapid arc extinguishing and industrial frequency blocking.According to the source form of arc extinguishing energy is divided into external energy type and self-propelled two arc extinguishing mode,and extended the invention of the corresponding arc extinguishing lightning protection device.Secondly,the complex laws of lightning bypass and counterattack on mountain lines are described separately,using the level of lightning resistance of the lines as a measure.Among them,when analyzing the winding,because the mountain line is extremely easy to appear across the valley,canyon,river valley of the large interval,equivalent to the ground settlement makes the winding exposure surface greatly increased,the maximum stroke distance rsmax calculated by the method of regulation is difficult to reflect the shielding ability of the lightning line,resulting in a winding rate higher than the plains area more than 60.From the rebound angle,the actual level of lightning resistance of mountain lines is constrained by the soil resistivity,such as soil resistivity ρ≥2000(Ω-m),the line lightning resistance level is less than 50 of the design value,the rebound rate climbs.In addition,the high incidence of multiple lightning strikes also threatens the safety of the route in terms of the form of mines falling.Thirdly,an arc magnetohydrodynamic model was established,by which the arc extinguishing mechanism of two arc extinguishing devices was analyzed.Among them,self-energy arc extinguishing device to the current itself in the arc extinguishing tube,pressure explosion effect as the trigger mechanism,in the current conduction instantaneous generation of strong cross-blowing air flow in the arc,and by the multiple fracture structure ejected,by repeatedly blowing the arc and repeated cooling to extinguish the arc does not reignite the purpose;external energy arc extinguishing device through the flashing current trigger TNT charging mechanism,resulting in the role of the arc longitudinal blowing strong airflow,explosive airflow of high pressure and continuity of the medium replacement to ensure the rapid recovery of air insulation,arc extinguished can not reignite.Further,the mechanism of one-to-one bundling of arc building and arc extinguishing in response to multiple lightning strikes is discussed,dividing the multiple into each execution of response and arc extinguishing actions to achieve protection against multiple lightning strikes.Fourthly,the experimental analysis of arc extinguishing devices,including insulation fit test,inrush current arc extinguishing test,frequency current extinguishing test,inrush coupled frequency current extinguishing test and combined installation method discharge test,various types of verification of the device response time,arc extinguishing characteristics,insulation fit ratio and other parameters,thus guiding the actual network installation.Finally,based on the actual experience of the author s participation in the project,representative mountain power transmission lines were selected and analyzed in terms of lightning protection scheme,connection hardware,insulation fit and installation,and application effect,and summarized the common protection methods of lightning protection devices under different voltage levels.These include 10 k V mountain distribution network lines,35 k V collector lines for wind farms in high minefield areas,110 k V typical mountain lines and 220 k V petrochemical dedicated lines.From the point of view of the application effect,the line lightning protection after the transformation of the line have greatly reduced the lightning strike trip rate and accident rate,the arc lightning protection device hanging network operation has achieved good results.