Electrical tree discharge channel will be formed at concentration position of electric field stress in solid insulation dielectrics due to electrical tree discharge.In order to study the characteristic difference of electrical tree under different electrical fields

a short-cable electrode system made of commercial XLPE cable was designed.Experiments on the short-cable electrode system and the common needle-plate electrode system were performed under 12kV

15kV

18kV

21kV

respectively.Experimental results show that the electrical tree of short-cable electrode system has the same growth trend compared with the needle-plate electrode system

the densities of both electrical trees increase with increasing voltage level

electrical tree of short-cable electrode system grows slower than the needle-plate electrode system under same voltage level

and the short-cable electrode system requires higher voltage level to achieve the same shape of electrical tree as the needle-plate electrode system.The results show that the semiconductor and copper shield layers outside of XLPE cable have very important effect on degradation of electrical tree.