To accurately analyze the back-flashover characteristics for canceling artificial grounding electrode in UHV double-circuit transmission line and discuss the suitable conditions for canceling artificial grounding electrode

we investigated the back-flashover characteristics of Zhebei-Fuzhou UHV double-circuit transmission line based on finite difference time domain（FDTD） method and leader flashover criterion by considering different tower height and soil resistivity. The results show that wave tail and peak value of the insulator string voltage will rise by canceling artificial grounding electrode. The closer the power line to the ground is

the more the gap voltage rises. The rising effect mainly depends on the soil resistivity. With the increase of soil resistivity

the effect of flashover gap voltage rise by canceling artificial grounding electrode is more remarkable. Especially

the air gap between middle phase of the power line and the lower cross arm is more likely to breakdown than the air gap between upper phase of the power line and the middle cross arm when the soil resistivity exceeds 1 500 ?/m2. We can cancel artificial grounding electrode when the soil resistivity is under 500 ?/m2 to guarantee the lightning withstand level exceeding 200 k A.