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Comparison and analysis on over-voltage and insulation coordination of UHV AC transmission system between China and Japan

The technology comparison and analysis on the over-voltage and insulation coordination of UHV AC transmission system between China and Japan have been carried out in this study, which may include the level of the power frequency temporary over-voltage, switching overvoltage and secondary arc current and the measures to restrict them, the lightning protection methods for transmission line and substation, the insulation level selection of substation apparatuses and the external insulation air clearance selection of the transmission line and substation. The corresponding UHV technologies of China and Japan have been selected based on their own characteristics of the UHV power grid. The research achievements may be helpful for the development of the international UHV transmission technology.