The cancellation of the overhead ground wire can avoid the line outage accident caused by the icing of the lightning protection line, but the probability of lightning strike failure of the transmission line increases. It is essential to study the lightning resistance performance of the line after the cancellation of the ground wire.To this end, this paper  establishes an electromagnetic transient physical model of 110 kV groundless transmission lines, uses ATP-EMTP software to simulate and calculate the lightning withstand level and lightning trip rate of the line, and analyzes the impact of the cancellation of the ground wire on the lightning resistance and pole strike rate of the transmission line. The results show that the tower grounding resistance, lightning current waveform, and 50% impulse discharge voltage of the insulator string have a significant impact on the lightning withstand level of the transmission line after the lightning protection line is canceled. Compared with grounding wire, the lightning resistance level of ungrounded transmission lines is reduced by 108.5%, and the lightning trip rate increased by 740%.After canceling the lightning protection line, the tower grounding resistance, lightning current waveform, and 50% impulse discharge voltage of insulator string have a significant impact on the lightning resistance level of the transmission line; At the same time, the lightning stroke rate of the line is related to the line sag, span, tower height, terrain, amplitude and probability of lightning current. Therefore, this paper proposes a lightning protection method for 110kV transmission lines without ground wire. The research results of this paper can provide a reference for canceling the lightning protection of transmission lines in multiple icing areas.
 

cancellation of ground wire, 110 kV transmission line, ATP-EMTP, lightning resistance level, lightning trip rate