Insulators are an important part of power equipment. However

the surface insulation defect is easily to lead to sudden flashover along the surface of insulators. In order to improve the detection ability of insulation defects and the surface flashover strength of insulators

in this paper the ZnS/BaTiO

3

doped insulation defect self detection composite coating is prepared

the ZnS:Cu electroluminescent materials are introduced into the insulation system to achieve self detection function of the defect. Moreover

the BaTiO

3

filler with high dielectric constant is introduced to make the surface electric field even and improve the flashover strength of insulators along the surface. The AC/DC flashover v

oltage of the coated sample is tested

and the detection ability of coating on the surface defect is observed. The result shows that thanks to the uniformizing effect of the composite coating on the surface electric field and the accelerated dissipation effect of surface charges

AC/DC surface flashover strength are effectively improved. In case of metal particle defect on insulator surface

the luminous brightness of the coating can effectively characterize the distribution characteristics of the surface electric field

and have a good detection ability for defects at the sub-millimeter level. The relevant experimental results have guiding significance for the application of the electroluminescent coating in the self-diagnosis of insulation defects and the improvement of the surface withstand electrical performance.