Contents I. Introduction
The prediction of lightning surge voltages is very important for rational and economical insulation designs of electric power and telecommunication systems. A number of experimental and theoretical studies on lightning surge phenomena have been carried out. in particular, the electromagnetic transient response of a ground grid has effects on induced surges in low-voltage and control circuits of power stations, substations, and telecommunication stations. Therefore, studies of the electromagnetic transient phenomena of a buried bare wire and a ground grid have been carried out [1]–[14]. However, these studies need verifications with field tests as follows.
The analytical examination of the buried bare wire and ground grid is based on Sunde's theoretical formulas [1]. However, it is not clear whether the theoretical formulas can reproduce the actual electromagnetic transient response of the buried bare wire and ground grid or not.
The comparison between the results calculated using Sunde's theoretical formulas and the experimental results using a real buried bare wire and ground grid system is insufficient. Therefore, it is impossible to apply the theoretical formulas for practical use.
