Touch & Step Potential for Lightning Protection System 1

[jayraj]

Touch and Step Potential calculations:
I am doing lightning protection design for a commercial workshop building using lightning rods and downconductors all connected to a earthing grid system as per the Australian standards AS1798 (1991).
I have not been able to calculate the touch and step potentials in the event of a lightning strike. Could anyone help, please.
Thanks

 

[alehman]

As a starting point, I would think you would have to assume a value for the lightning strike current. I don't have access to AS1798. Does it specify this?

 

[jghrist]

This is a very difficult calculation because the impedance of the grounding system is very frequency dependent and a complex electromagnetic analysis is required. See Study of Transient Ground Potential Rise in Gas-Insulated Substations during Fault Conditions using Electromagnetic Field and Circuit Theory Approaches at

http://www.sestech.com/software_packages/pdf/User2000_A.pdf