“…These traveling waves repeat reflections at the GIS ends and branches, finally becoming highly complicated waveforms. At the same time, it has been noted that there is a possibility that the levels of FTO exceed 3.0 pu (1 pu is the crest value of operating voltage) [2]. Further, as problems involving FTO, not only is the phenomenon of flashover to ground from interpo1e arcs of operating disconnectors [3,4] discussed, but also the influences on transformers, bushings, and other devices [5].…”