The Study Of Arc-extinguish Effect For Continuous-trigger Jet Stream Lightning Protection Gaps Based On Energy Balance Theory

Parallel clearance is a kind of lightning protection method commonly used in overhead lines,which can effectively protect the line insulator from AC arc ablation,but because of its lack of arc extinguishing ability,it is easy to cause the transmission line to trip and affect the power supply stability.In order to effectively extinguish the power line arc of the transmission line and prevent it from causing the arcing of the arc due to the power frequency power supply or multiple countermeasures,the lightning strike rate is greatly reduced,and a continuous trigger jet airflow is studied.The device through the continuous trigger of the two high-speed air flow,while extinguishing the arc while continuing to accelerate the convection of the arc convection,to suppress the arc reignition.At the same time,for many times the cause of the reignition caused by the reignition of the arc,the device through the rapid switching of the arc energy to do a one-to-one response,to suppress the reignition.Based on the C-J theory of explosive mechanics,this paper first studies the mechanism of injection in the arc-quenching gap,and establishes a mathematical model of high-speed and high-pressure airflow shock wave.Then,based on the theory of arc energy balance,the mechanism of AC arc extinguishing is analyzed,and three ways of energy loss of arc channel are studied.The model of airflow coupled arc is established.The numerical simulation of the whole process of extinguishing the alternating arc and suppressing its reignition is carried out by ANSYS Fluent software,and the model established above is numerically solved.After simulating,7.1 ms,the average temperature of the arc channel Ta is lower than 3000 K for the first time,and the arc is extinguished.After that,the jet flow continues to heat dissipate the entire channel and suppress the arcing.In the laboratory environment,the simulation of the device single arc test and multiple trigger experiments.The experimental results show that the double-trigger jet air extinguishing lightning clearance can extinguish the arc within 8 ms,and for the two lightning strikes with a time interval greater than 20.7ms,the device can be triggered by repeated triggering of the extinguishing gas AC arc.Continuous trigger jet airflow arc gap has been applied to two lines,after a year of trial operation results,line lightning strikeout rate,lightning accident rate dropped significantly,and can protect the 200kA class lightning repeatedly hit back.