| Lightning is the first killer of power grid,which seriously affects the reliability of power grid,and its protection is a world-class problem.Therefore,strengthening the lightning protection of transmission lines is the key to reduce lightning accidents and improve the reliability of transmission lines.In order to break through the bottleneck of "blocking type" lightning protection,in recent years,"Dredging" type lightning protection has made great progress.However,there still exists the problem of "Dredging" lightning protection arc cannot be extinguished.On the other hand,the principle of arc compression and the phenomenon of "cathode jet" have been studied for a long time,but the feasibility of its application in the field of lightning protection and arc extinguishing is still need to be demonstrated.In order to solve the problem of lightning protection,the arc compression principle and the "cathode jet" phenomenon are applied to the field of arc extinguishing and lightning protection.A method of compression arc suppression and lightning protection has been developed,and a compression arc extinguishing and lightning protection device has been invented.The lightning protection effect of the compression arc extinguishing and lightning protection device is verified by theoretical analysis,simulation and experimental verification.The specific research contents are as follows:(1)A one-dimensional arc column model of arc column is established,and the principle of arc compression and the phenomenon of "cathode jet" are analyzed.The compression mechanism of the compression tube is mechanically self magnetically mechanical.Under this compression mechanism,there are two changes in the barber of the arc machine:The diameter of the arc column is extremely reduced,and the temperature and flow density are significantly improved;The axial pressure of the arc changes to a radial pressure by squared times,and the magnetic attraction makes the cold gas molecules accumulate in the compression pipe.The former is the energy source that produces the arc extinguishing air flow,and the latter is the material basis.The heat transfer process of the arc-gas-wall system is analyzed,which makes the gas pressure increase extremely and the arc extinguishing ability is strong.The chain arc model is established to quantify the force analysis and calculate the speed of the arc under the action of expansion airflow,and compare the result with the extinction criterion.(2)The finite element analysis software FLUENT is used for simulation analysis.The simulation results show that the airflow that makes the arc extinguished will follow the change of the arc current,and the arc appears broken at 0.2 ms,but because of the physical inertia of the airflow,the attenuation speed is much less than the decreasing speed of the arc temperature.And the "tail gas" is enough to suppress the arc rebuming.(3)The arc extinguishing test of high current arc shows that the response speed of the device is fast and the power of the arc extinguishing airflow is strong,which causes the arc to appear at 0.3ms,and the 1.5ms is completely extinguished,and there is no arc reburning phenomenon.The device can effectively extinguish thousands of high current arcs.The lightning voltage test has found and solved the insulation defect of the device.It is found that the device has the ability to extinguish arcs with only tens of Annes.Compared with the large and small arc extinguishing test,the following conclusion can be concluded:The compression arc extinguishing and lightning protection device has adaptive arc extinguishing ability in the range of tens of amps to thousands of ampere arc currents.The theoretical analysis,the simulation process and the test results mutually support and mutually prove the validity of the compressing and extinguishing lightning protection device to solve the problem of "dredging type" for lightning protection and arc extinguishing,and prove the feasibility of the arc compression principle and the "cathodic jet" phenomenon applied to the field of lightning protection and arc extinguishing.The practical application of the device proves the truth of theory,simulation and experiment. |
