The Kii Channel HVDC system in Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

 is, as of 2010, the highest-capacity high-voltage direct current

High-voltage direct current

A high-voltage, direct current electric power transmission system uses direct current for the bulk transmission of electrical power, in contrast with the more common alternating current systems. For long-distance transmission, HVDC systems may be less expensive and suffer lower electrical losses...

 (HVDC) submarine power cable

Submarine power cable

Submarine power cables are major transmission cables for carrying electric power below the surface of the water. These are called "submarine" because they usually carry electric power beneath salt water but it is also possible to use submarine power cables beneath fresh water...

 system in the world. The Kii Channel

Kii Channel

The is a strait separating the Japanese Home Islands of Honshū and Shikoku. This channel connects the Inland Sea with the Pacific Ocean....

 HVDC system connects the Anan static inverter plant

Static inverter plant

A static inverter station, also known as an HVDC Converter Station, is the terminal equipment for a high-voltage direct-current transmission line, in which direct current is converted to three-phase alternating current, and, usually, the reverse...

, located south of Tachibana Power Plant, at 33°49′40"N 134°38′14"E on the Japanese Home Island of Shikoku

Shikoku

is the smallest and least populous of the four main islands of Japan, located south of Honshū and east of the island of Kyūshū. Its ancient names include Iyo-no-futana-shima , Iyo-shima , and Futana-shima...

, with the inverter plant at Kihoku

Kihoku, Mie

is a town in Kitamuro District, Mie, Japan. The town was founded on October 11, 2005 from the merger of the towns of Miyama and Kiinagashima.As of April 1, 2010, the town has an estimated population of 18,283 and density of 71.1 persons per km². The total area is 257.01 km². Kihoku is surrounded...

 ( coordinates: 34°12′50"N 135°30′07"E) on the largest of the Home Islands, Honshu

Honshu

is the largest island of Japan. The nation's main island, it is south of Hokkaido across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyushu across the Kanmon Strait...

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History

The first stage of this project went in service in the year 2000 with a bipolar voltage of 250 kilovolts (kV) and rated to carry 1400 megawatts (MW). The first 50 kilometers of the transmission line run north from the Anan inverter station as an undersea cable.

At Yura ( coordinates: 33°58′37"N 135°05′20"E ) there is a switching station, and from there the HVDC line runs for another 50 km as an overhead power line

Overhead power line

An overhead power line is an electric power transmission line suspended by towers or utility poles. Since most of the insulation is provided by air, overhead power lines are generally the lowest-cost method of transmission for large quantities of electric energy...

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