Electric field distribution of cable insulation is a main factor affecting the long-term and reliable operation of HVDC cable. Nonlinear materials can not only homogenize the electric field distribution by themself

but also have obvious inhibition effects on electrical trees growth and the formation of space charge. Therefore

we tried to use a nonlinear material as barrier layer and put it between shield and insulation.Moreover

we established a simulation model by the software of COMSOL Multiphysics. Meanwhile we studied the influences of barrier layer structure on the steady and transient electric field distribution and space charge of HVDC cable insulation at different temperature gradients. The simulation results show that

compared with the non-barrier cable

the steady and transient electric field strength maximums of the cable insulation with nonlinear barrier layer are both decreased. That is to say

the injection of space charge into insulation is inhibited and the distribution of electric field is improved by the barrier layer structure. As the barrier layer thickness increases

the space charge in the insulation and the maximum field strength decreases

but the interface charge increases. According to the simulation results

the electric field distribution of cable insulation can be optimized by a barrier layer. However

it also causes the accumulation of interfacial charge. Therefore

when HVDC cable with a nonlinear barrier layer structure is developed

the interface charge accumulation and electric field distribution should be considered for the selection of barrier layer thickness

so as to improve the cable insulation performance.