Sakuma Frequency Converter Project

Power system frequency has developed on a 50-cycle basis in northern Japan and on a 60-cycle basis in the south. Past efforts to unify the frequency have been unsuccessful. Both systems have now developed to the extent that this is now virtually impossible. To obtain the advantages of interconnection, despite this handicap, modern high-voltage dc techniques are used. In a single station, 50-cycle power is converted to direct current and direct current to 60 cycles (or vice versa). This is, in effect, a de transmission system without a line. However, location of both rectifiers and inverters in the same station permits some simplification over a conventional dc tie.