Abstract: In order to simulate the ignition process of the outer sheath under the fault arc and investigate its ignition characteristics, this paper proposes an electrode arc ignition simulation method, based on the energy balance equation of the arc ignition process and experimental data, analyses the impact of the electrode speed and circuit current on the arc ignition stability, and determines the relationship between the different current conditions and the electrode speed and arc power. The results show that under the same circuit current condition, when the electrode moving speed is too fast, it will lead to a shorter arc ignition time and cannot ignite the outer sheath; while when the electrode speed is too slow, it will lead to the burning carbide connecting the two poles, and the arc will be extinguished prematurely, with a short combustion duration; there is a certain range of electrode speeds corresponding to different circuit current conditions, and both the upper limit and lower limit of the speed are positively correlated to the size of the circuit current. Using the relationship between the determined circuit current and the electrode speed, the simulation of the ignition of the outer sheath under the action of the arc is achieved by taking the 35 kV high-voltage cable as an example, which shows that the simulation method in this paper can successfully ignite the outer sheath of the high-voltage cable and sustained combustion occurs under the action of the arc.

Key words: ignition of electric arc, arc of fault, fire simulation, cable fire