Tower and Gantry

Ztl is the tower top to the upper phase arm=upper to middle=middle to lower. 

Measured results of lightning current amplitudes. (From IEEE Guide for Improving the Lightning Performance of Transmission Lines, 1997 Ametani, A. et al.. Power system transients and EMTP analyses, lEE Japan WG Report. Tech. Rep. 872, 2002 CRIPEI WG, Guide to transmission line protection against lightning. Report T72, 2003 Ametani, A. and Kawamura, T., IEEE Trans. Power Deliv., 20(2), 867,2005 Anderson, R.B. and Eriksson, A.J., Electra, 69,65,1980.) 

The propagation velocity c of a traveling wave along a tower is taken to be 

T = U/Cq is the traveling time along the tower al = a4=0.89 is the attenuation along the tower h is the tower height 

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