Abstract: This paper explores the damage risk of adjacent cables when arc ignition occurs in the outer sheath of high voltage cables. Firstly, a high-voltage cable arc ignition test platform was built, the 110 kV flame retardant cable was used as the test material. The typical arc fault conditions were selected to carry out the arc ignition test, and the ignition characteristics of the cable outer sheath were analyzed. Then, the equivalent fire source simulation model was established according to the ignition test data, and the temperature rise characteristics of the sheath combustion were verified. Finally, taking a typical cable tunnel as an example, the temperature distribution simulation and the risk assessment of adjacent cable damage were carried out. The results show that the maximum flame temperature under 4~10 A typical arc condition is 310~725 ℃, and the equivalent fire source power is about 128~275 W. When the fault arc current is less than 8 A, there is no risk of damage to the cables in each layer of the tunnel; when the arc current is 8 A and above, the surface temperature of the upper laying cable on the same side of the fault cable exceeds the safety limit 30 s after the arc fault occurs, and there is a risk of damage.

Key words: fault arc, ignition characteristics, damage risk, cable combustion