In order to improve the arc quenching ability of the multigap system, it is important to know the principle of arc quenching and how the chamber structure affects the arc development process in the multigap system. In this study, the twodimensional geometric model of the multigap system is established based on the magnetohydrodynamics theory in COMSOL multiphysics simulation platform. The principle of arc quenching in the multigap system is explained in detail by analysing the physical characteristics of the arc in the multigap system. The simulation result shows that the arc is compressed at large scales in the semi-closed chambers of the multigap system, which results in an instantaneous temperature rise of the arc, thus, forming the self-expanding airflow. The strong self-expanding airflow cuts off the arc channel and blocks the energy supply of the arc. The influence of the chamber structure on arc quenching in the multigap system is manifested in the fact that proper improvement of the width and depth of the chamber subserves arc cooling, the reduction of the deflection angle and the increment of the number of the chambers are conductive to arc extinction.

To reduce the damage from the power frequency follow current of distribution lines, a multi-fracture compression airflow arc-extinguishing structure is studied. The structure is mainly composed of a compression tube, a metal electrode, and metal connection fittings, and the multi-fracture compression airflow arc-extinguishing body is formed by the combination of packaging and insulation fittings. The body and the air gap are parallel to both ends of the insulator. When lightning strikes, the internal short gap of the main body and the air gap break down, and the lightning arc enters the arc-extinguishing body through the breakdown channel. In the structure, the arc is compressed by force to form internal and external gradients of temperature and to produce jet airflow. The jet airflow acts on the subsequent power frequency follow current arc, which is suppressed and extinguished. In this paper, a model coupling an arc and a compressed jet airflow in a multi-fracture compression airflow arc-extinguishing structure is established theoretically and simulated by simulation software. Finally, a power frequency follow current interruption test is carried out. The simulation results show that a high-speed airflow of 600 m/s is formed around the fracture at approximately 0.99 ms, and the airflow is proportional to the rate of temperature variation. The test results show that the power frequency follow current of 1.289 kA is cut off within approximately 3 ms without a reburning phenomenon. The effect of power frequency follow current interruption is obvious in the structure.

In order to reduce the lightning trip-out rate of grid power lines, a kind of impulse quenching based multichamber arc quenching structure (IQBMAS) is developed by the authors. This kind of MAS can attract the lightning impulse arc into its arc quenching channel and truncate the impulse arc into multiple parts rapidly. In this case, the impulse arc will not develop into steady power frequency current, so the lightning trip-out can be avoided. In this paper, simulations and experiments are conducted to verify the arc-quenching effect of IQBMAS on the basis of expounding the operating principle of IQBMAS, establishing the arc model in the channel as well as deriving the relevant numerical equations. The test result shows that IQBMAS can extinguish the power frequency arc of 10 kV lines within 1.5 ms with no reignition.

To avoid the restriction of the arc energy on the energy quenching of an arc and rapidly quench the arc to restore the insulation characteristics of the gas, the process of arc quenching by an explosion air shock wave is studied in this paper. The interaction between an explosion air shock wave and an arc is considered inside a cylinder structure so that concentrated pressure and airflow velocity can be produced. First, a coupling model of the explosion air shock wave and arc is developed theoretically. Second, according to the model, the explosion air shock wave and arc are simulated by finite element simulation software. It is found that the interaction between the explosion air shock wave and arc is most intense at 0.04 ms, the arc is driven out of the cylinder at 0.087 ms, and then, the arc is gradually quenched. Finally, the test results show that the arc is completely quenched at approximately 0.80 ms, and the value of the peak current is 1 kA. Although there is error between the simulation and test results, the effectiveness of the explosion air shock wave in quenching the arc is still verified, and the arc is quenched over a time scale of milliseconds.

A dual-jet arc-extinguishing method is proposed in order to improve the performance of jet-extinguishing gaps for extinguishing large currents and reducing the lightning trip-out rate of power lines. Meanwhile, we studied the arc-extinguishing effect of the dual-jet non-equilibrium field gas flow. Based on this, a Double Jet Arc Extinguishing Gap (DJAEG) is developed. First of all, the jet field arc extinction modeling analysis is carried out by coupling the typical MAYR arc model with the jet field. Then, the COMSOL MUTIPHSICS simulation software is used to simulate the arc extinction of the DJAEG in the balanced flow field and the non-balanced flow field. Finally, the DJAEG extinguishment arc test is carried out through the construction of the power frequency continuous flow interruption test. The simulation results show that the velocity of the high-speed jet emitted by the DJAEG can reach 3000 m/s, and the arc can be extinguished within 4 ms. These results also verified that the dual jet non-equilibrium flow field has the characteristics of long jet sustaining time. The test results show that the DJAEG successfully extinguished the arc within 4 ms, and there was no reignition. This means that the dual-jet non-equilibrium field has an obvious arc extinction effect.