Research On Truncated Arc Self-Extinguishing Mechanism And Test Of Arc-Extinguishing Lightning Protection Gap Under Explosive Airflow Pressure

With the constant construction of China’s power grid and rapid development of UHV lines, the lightning protection of overhead lines becomes more and more important. Lightning activities throughout the various provinces and cities in China, insulator damage, line disconnection and power outages caused by lightning flashover are very common, and it occupy a large proportion in the line trip accident. Aiming at the problem of poor effect of "blocking type" lightning protection mode, we put forward the lightning protection method by combining "scatter type" with explosive airflow gas-blowing.This article study on parameter change of arc development from the volt-ampere characteristics of AC arc, arc column potential gradient, temperature and diameter characteristic. Establishing arc self-extinguishing ion model, from microscopic point of view analyzing the destructive effect of explosive airflow on arc. Further analyzing the effect of explosive airflow on dielectric recovery strength.The force analysis of AC arc is carried out according to the chain arc model, The relationship between arc movement characteristics and explosive airflow pressure are deduced through airflow pressure calculation under explosive airflow. And draw arc self-extinguishing time combined with arc self-extinguishing time simulation process. Secondly, establishing AC arc MHD model, the blast area particle arc mathematical model and gas energy variation of explosive airflow model. Using ANSYS14.0 finite element software to couple explosive airflow and AC arc, simulating the process of explosive airflow cutting arc and airflow pressure distribution, and simulating dynamic process of arc self-extinguishing after explosive airflow occurred. Finally, building a test platform for self-extinguishing test of explosive airflow pressure cut-off arc. Arc self-extinguishing time was obtained by the mathematical statistics of multiple test data under the effective insulation coordination, And the relationship between explosive airflow velocity and arc self-extinguishing time is obtained. Further analyzing actual hanging network operation of arc-extinguishing lightning protection gap. On the high lightning frequency lines had good running effect, which consistently proves that AC arc can self-extinguish under explosive airflow pressure when lightning strikes.