Application And Research Of The Arc Cutting Off Mechanism Under The Action Of High-speed And Strong-pressure Explosion Airflow

China s transmission lines are widely distributed,the environment is complex and the lightning activity is increasingly frequent,making lightning the primary cause of transmission line trip accidents.The main measures of the existing lightning protection technology for transmission lines are to increase the insulation strength and improve the lightning protection level.However,due to the inherent defects of these lightning protection measures,the lightning protection of transmission lines becomes a problem.AiminLg at the problems in the existing lightning protection technology,a new lightning protection technology is proposed:high-speed and strong-pressure explosion airflow arc-extinguishing technology.Based on the analysis of the physical characteristics of the arc,this paper analyzes the free ability of the arc according to the physical parameters such as volt-ampere characteristics,potential gradient,temperature and diameter of the arc,and explains the principle of extinguishing and reburning of the AC arc.According to the energy balance process of the arc,the arc can be regarded as a high temperature fluid,whereby basic models of the arc fluid can be established.After that,the paper expounds that the high-speed and strong-pressure explosion airflow is an air shock wave,and its properties accord with the basic equation of aerodynamics.Then,the CJ detonation theory and the ZND detonation model combined with the propagation characteristics of the air shock wave can establish the expression of the explosion airflow.After combined with the basic equation of the arc,the dynamic energy model of the arc under the action of the longitudinal airflow is finally obtainedThe arc under the action of the longitudinal airflow and the temperature field and velocity field in the arc chamber are simulated and analyzed by the FLUENT software.The results show that the arc is extinguished within 3ms,the peak velocity of the explosion airflow reaches 450m/s,and the high speed status is maintained for a long time.In order to verify the validity of the paper,the energy block response time measurement test and the arc extinguishing test of the explosion airflow arc-extinguishing device were carried out.According to the data,the energy block can respond within 0.2ms,and the arc is extinguished within 4.2ms under the action of the explosion airflow.Finally,combined with the long-term application on the transmission line,the effectiveness of the explosion airflow arc-extinguishing device is proved.