Abstract: The transient process caused by lightning stroke to the top of high transmission tower is of great importance in the design of the application of the transmission line, line insulator and arrester. In this paper the existing surge impedance models for transmission towers home and abroad are introduced in brief, to improve the model, on this basis the tower body is divided into different pieces, considering the impact of equivalent radius and then analysis the influence of lightning propagation. Through the contrastive analysis of the segments of the tower, the lighting current waveform, and the amplitude of lighting current, and surge impedance effect on the transient characteristic of the tower, combining theoretical analysis, from which we can find that the subdivision of the tower will reduce the overvoltage and prolong the transient process. The conclusion is available for reference to the design of high transmission tower.

Key words: tower, surge impedance model, lighting, transient analysis