Experimental and Analytical Studies on Lightning Surge Response of 500-kV Transmission Tower

This paper presents experimental and analytical studies on the lightning surge response of a 500-kV transmission tower without overhead lines. A number of experimental studies on the lightning surge response of transmission towers have been carried out. However, in these studies, the influence of the current injection angle was ignored. In this paper, an experimental investigation is conducted to assess the influences of the angle and direction of current injection. It is clearly shown that the lightning surge response of the tower depends on the angle and direction of current injection. These experimental results are compared with results calculated using numerical electromagnetic (EM)-field analysis. These calculated results agree with the experimental results. This suggests that numerical EM-field analysis can be employed for evaluating the surge response of a tower. Based on this, the surge response of a tower under a vertical lightning stroke is estimated. It is shown that the surge response under vertical current injection is approximately 30% higher than that under horizontal current injection. It is also shown that the angle and direction of the return stroke are important factors in determining the lightning surge response of a transmission tower.