Abstract :
To strengthen electric-power networks, their linkage over broad areas is desirable. Japan is a long, archipelagic country consisting of four major islands, namely Hokkaido, Honshu, Shikoku, and Kyushu, from the northeast to the southwest. Power networks in the four islands are connected with each other, either under water or on land. Among these connecting power lines, those between Honshu and Shikoku and between Honshu and Hokkaido are dc submarine lines; there is also an onland ac line between Honshu and Shikoku carried on a series of bridges connecting the two islands.
