High voltage substations are the main part in any power system utilities or
municipalities. Proper design of lightning protection system should be done in the
preliminary stage of the design process. In this paper, a typical high voltage substations of
500/220 kV is modeled by developing multi-scripts of Matlab m-files. To allocate and to
simulate the whole carrying current conductors inside the substation and with 100 m length
of input and output power lines. This is to calculate and to demonstrate the lightning
electromagnetic fields inside the substations during lightning conditions using the Finite
Difference Time Domain (FDTD) method with Maxwell’s equations. The effects of the posts
allocations, its heights and surge arrestors to secure optimum protection zones are
investigated. The electromagnetic fields distribution around the posts and inside the entire
area of the substation during lightning conditions are evaluated. The electromagnetic fields
for lightning over the input/output power lines are depicted to stand precisely of how much
of interference with the electronic devices inside the control room during the very small
lightning interval. The obtained results while lightning strikes the masts or input/output lines
show a reasonable deviation between the electromagnetic field values and the regulation
standards.