| The safety problems and economic losses caused by lightning trip accidents are immeasurable.Preventing lightning trip has become a major issue for the safe and stable operation of transmission lines.Scholars at home and abroad have made some achievements in lightning protection of transmission lines,and have been widely used in transmission lines.However,the long-term stability of tripping rate has not been significantly improved,indicating that the existing lightning protection measures still have shortcomings.Based on the existing lightning protection technology,this thesis innovatively designs a gas arc extinguishing lightning protection device suitable for 35 k V and below voltage level,which provides a new idea for the development of transmission line lightning protection.This thesis first analyzes the basic physical characteristics of AC arc,studies the shape change of arc after entering the arc extinguishing device,the reason of producing high-speed longitudinal blowing air flow and the arc attenuation characteristics at the turning point of adjacent arc extinguishing pipe.Based on the relationship between arc energy balance,Mayr dynamic arc model and MHD equation are used to build a high-speed air longitudinal arc model in arc extinguishing tube.Using mayr arc model to build 10 k V transmission line,the simulation results show that the larger the arc dissipation power is,the easier the arc is to be extinguished.As an important factor affecting the dissipation power,the gas velocity can be intuitively obtained that increasing the gas velocity,that is,increasing the dissipation power is helpful to accelerate the arc extinction.According to the high-speed gas longitudinal arc model,the two-dimensional geometric model of adjacent arc extinguishing pipeline is built on COMSOL simulation platform,The changes of temperature,conductivity and velocity of arc in the pipeline under the action of high-speed airflow are analyzed,and the influence of these three factors on arc extinction is analyzed.Then,through the type test of 10 k V arc extinguishing device,including lightning 50% impulse discharge voltage test,impulse voltage second characteristic test,power frequency withstand voltage test and impact combined power frequency arc extinguishing test,the effectiveness and safety of arc extinguishing device can be verified;the insulation coordination test for 500 k V solid-phase compression combined lightning protection device for ultra high-voltage transmission line can be obtained The end of the thesis is to optimize the arc extinguishing tube and the arc conducting electrode of arc extinguishing device,aiming to improve the arc extinguishing capacity of the device,and design a recoil compression device,and carry out the arc extinguishing test of impulse current to verify its withstand and arc extinguishing capacity,which lays the foundation for the subsequent research;according to the actual application situation,the arc extinguishing device is installed The trip rate of lightning stroke of the line is greatly reduced,and the cost-effective is simple and convenient in installation and maintenance,and the economy of lightning protection is effectively improved. |
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