Revision, extension, and validation of Jordan's formula to calculate the surge impedance of vertical conductors

Jordan's formula to calculate the surge impedance of vertical conductors is revised and extended to take into account systems with multiple conductors. Experimental data and the hybrid electromagnetic model are applied in order to validate the derived expressions. Additionally, Jordan's formula is successfully used in the representation of an actual tower as a multiconductor vertical system. The obtained results indicate the usefulness of the derived expressions if an engineering analysis of direct strikes over elevated strike objects is required