抄録
A number of studies on the surge impedances of transmission towers and transmission lines when lightning struck have been carried out theoretically and experimentally. However, the theoretical studies could not always explain the experimental results. This paper derives new formulas of the surge impedances of the transmission towers and transmission lines for the lightning surge based on an electromagnetic field theory. A comparison of results calculated by the proposed formulas with the experimental results show nearly the same wave crest values and waveforms. It is not clear how much current flows into ground wires and the tower from the input current source. It is made clear that a large portion of the input current flows into the tower and a small current flows into the ground wires. This fact is very important to investigate lightning performance in the transmission towers and the transmission lines. The above results are useful to develope accurate models of the transmission towers and the transmission lines for the lightning stroke.
