In recent years

the ablative failure of buffer layer of HV corrugated aluminum-sheathed cable occurs frequently. The suitable interference fit distance between the cable aluminum sheath and the buffer layer can reduce the possibility of ablation failure. This paper carries out the test of the resistivity of the buffer layer under different deformation distances. Based on the optimal two-segment linear fitting results of the curve

this paper puts forward a method of determining the turning point of the deformation characteristic curve of buffer layer resistivity

establishes an electric-thermal field computation model of HV corrugated aluminum-sheathed cables with spatially non-uniform distribution of the resistivity of the buffer layer due to the local compression and deformation of the buffer layer. This paper analyzes the influences of different deformation distances and the number of bad contact points on the maximum value of current density and temperature rise of the buffer layer

and finally puts forward the recommended value of the interference fit distance of the buffer layer. The results show that the maximum values of current density and temperature rise of the buffer layer

when taking into account the resistivity deformation characteristics of the buffer layer

are 1.3 and 26.6 times higher than those of the uniform resistivity model of the buffer layer in the existing literature under the worst calculation conditions of this paper

i.e.

the number of bad contact points is 49

and the interference fit distance is 0.1 mm

respectively. At the same time

the results explain the phenomenon that the current density of the buffer layer concentrates towards its good contact position with the aluminum sheath

and provide a theoretical basis for the fact that ablation failures mostly occur here. The increase in the number of poor contact points will lead to an increase in the buffer layer current density and temperature rise; however

only when the buffer layer deformation distance is less than the critical deformation distance

the increase is more obvious. Therefore

the critical deformation distance of the buffer layer resistivity deformation characteristics of the buffer layer can be used as the recommended value of the buffer layer interference fit distance. The interference fit distance between the 2 buffer layers and the metal sheath is recommended to be about 0.72 mm.