In recent years

multiple buffer layer ablation failures occurred in domestic cables with voltage levels of 110 kV and above. In this paper

the finite element method is used to establish an axial simulation model of HV cable

and the electro-thermal coupling simulation is carried out to study the distribution of temperature field of corrugated aluminum sheath operating in a normal situation and in the case of air gaps between buffer layers. The simulation results show that when there is an air gap between the corrugated aluminum sheath and the buffer layer

it is disadvantageous for heat dissipation

and thus ampacity decrease of cables; air-gap discharge aggravates the erosion of the buffer layer

and the temperature rise in the center of heat source can reach up to 470 K

but the macroscopic effect of short-time air gap discharge on the cable temperature distribution can be ignored before the water-blocking powder is separated out.