The insulator of a high-voltage transmission line supports the wire and prevents the current from flowing back to the ground. However

flashover may occur on it when transmission line is subject to lightning or operation overvoltage

and it may even be burned or crushed. To ensure safe work of the insulator

the insulator is usually paralleled with an arrester

whereas this parallel layout will increase the load of line and tower due to the large volume and weight of the arrester

and will make transmission facility complicated. In addition

additional equipment on tower arm will result in inconveniency in installation of the arrester. In this paper

an lighting-protective insulator is designed

its electric field is optimized

and simulation is performed to verify its mechanical properties. The results show that this integrated device can meet the requirements for both insulator and arrester. It is concluded that the lighting-protective insulator for 110 k V transmission line is feasible.