Abstract: The distribution lines are densely distributed with low insulation strengths and lightning resistances in our country. In addition, there are high incidences and high risks of lightning damages. So it is of important research meaning to reduce the lightning trip rates and ensure the reliable operation of the distribution lines. The arc extinguishing device with multiple and tortuous breaks is a self-energy gas arc-extinguishing device, which is able to greatly reduce the lightning trip rates. In this paper, based on the theory of MHD (Magnetohydrodynamics), the arc formation and extinguishment and the generation principle of the self-expanding airflow in the device are analyzed. The two-dimensional geometric model of the arc extinguishing device is established by using the COMSOL Multiphysics simulation software. By analyzing the simulation results, the continuous competition process between the air flow energy and the arc energy in the whole arc extinguishing process is elaborated in detail. According to the IEC standard, the power frequency continuous current interruption test platform is built, and the power frequency continuous current interruption test is carried out. The experimental results indicate that the equipment is able to extinguish the power frequency continuous current with the peak value of 1.5kA in approximately 800μs. The actual line operation data shows that the device may effectively extinguish the arc and significantly reduce the lightning trip rates.