Study On Lightning Protection Of Multibreak Gas Blast Arc-quenchin Device Used In The Distribution Network

Overhead transmission lines are exposed to complex and changeable natural environment,which are affected by many uncontrollable factors,in which lightning disasters are the main factors that cause line tripping.China's distribution network is winding,widely distributed and low in insulation level,so it is more vulnerable to lightning damage.With the acceleration of urbanization and the improvement of living standard,the importance of distribution network is becoming more and more prominent on the user side.This paper developed a multi breakpoint gas blowout device,which can effectively prevent the lightning.In this paper,the physical properties of the arc are introduced,including the voltage characteristics,the volt ampere characteristics,the temperature and the radius of the arc,and the relationship between them is described.Besides,the self-magnetic compression characteristic of arc is expounded from the angle of electricity and magnetism,which provides evidence for the theoretical analysis of multi break arc extinguishing and lightning protection device.The energy dissipation of arc is mainly in the way of conduction and convection,so increasing the speed of the gas medium around the arc will accelerate the quenching of the arc.By analyzing and studying the existing arc model,the Mayr arc model after MATLAB simulation is selected,and it is concluded that the arc can be extinguished at about 11.3ms when the arc is naturally zero when the arc is not forced.After the arc enters the arc extinguishing channel,it is compressed by three aspects of the channel wall the self-magnetic field and the expansion airflow,so that the arc energy concentrates on the axis of the channel.And compression makes the high-speed airflow generated at the center of the shaft,forming strong longitudinal blow on the arc.Combined with the channel model and the longitudinal blow model,a plasma based development arc model,consisting of mass conservation,momentum conservation,energy conservation,adiabatic equations and electromagnetic equations,is proposed.This model can show the coupling process of airflow and arc more comprehensively.The simulation analysis shows that the air flow acts on the arc and truncated it in the time of 0.1?0.12ms.The energy of the impact arc can be rapidly converted into the kinetic energy of the airflow,and the energy of the impact air is much larger than the energy required for the continuous discharge of the arc.After the arc is extinguished by the impact air,the pressure of the arc extinguishing channel becomes very low,which is close to the vacuum state.Therefore,the arc rebuming is deeply suppressed.The arc extinguishing test proves the effectiveness of the lightning protection device,and the very strong interaction between the high-speed air flow and the arc can be seen in the test.Normally,the device will not affect the operation of the line.When the line is subjected to lightning stroke,the device can protect insulator string.The data of arc extinguishing test show that the speed and speed of arc extinguishing device are very fast and the arc is extinguished during the attenuation period of impact energy.The arc is truncated and not refired in about 0.2ms.The test results show that the 50%impulse voltage of the lOkV arc extinguishing device parallel to the column insulators is about 86.85kV.The test data show that the volt second characteristic curve of the multi break point air blow arc extinguishing device meets the requirements of the protective insulator,and it can precede the insulator string breakdown.The actual application also verifies the effectiveness of the multi break point air blow arc extinguishing and lightning protection device,which is worth promoting.