The Kii Channel HVDC system in Japan is, as of 2012, the highest-capacity
high-voltage direct current
A high-voltage direct current (HVDC) electric power transmission system (also called a power superhighway or an electrical superhighway) uses direct current (DC) for electric power transmission, in contrast with the more common alternating curre ...
(HVDC)
submarine power cable
A submarine power cable is a transmission cable for carrying electric power below the surface of the water.cross channel system between England and France has a larger total capacity, but uses two bipoles rated at 1000MW each.
The
Kii Channel
The , also called the Kii Strait, is a strait separating the Japanese island of Shikoku from the Kii Peninsula on the main island of Honshū. This strait connects the Inland Sea with the Pacific Ocean.
The name of the strait derives from Kii P ...
HVDC system connects the Anan
static inverter plant
An HVDC converter station (or simply converter station) is a specialised type of substation which forms the terminal equipment for a high-voltage direct current (HVDC) transmission line.Arrillaga, Jos; High Voltage Direct Current Transmission, se ...
Shikoku
is the smallest of the four main islands of Japan. It is long and between wide. It has a population of 3.8 million (, 3.1%). It is south of Honshu and northeast of Kyushu. Shikoku's ancient names include ''Iyo-no-futana-shima'' (), ...
, with the inverter plant at Kihoku on the largest of the Home Islands,
Honshu
, historically called , is the largest and most populous island of Japan. It is located south of Hokkaidō across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyūshū across the Kanmon Straits. The island ...
.
History
The first stage of this project went in service in the year 2000 with a bipolar voltage of 250
kilovolt
The volt (symbol: V) is the unit of electric potential, electric potential difference (voltage), and electromotive force in the International System of Units (SI). It is named after the Italian physicist Alessandro Volta (1745–1827).
Defi ...
s (kV) and rated to carry 1400
megawatt
The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after Jame ...
s (MW). A second-stage upgrade to 500kV has been planned from the outset and the HV cable, DC switchgear and DC reactor are already rated for the higher voltage, but as of 2012 the upgrade has not been put into effect.
The project contained several "firsts" when it was originally built, including:Shimato, T., Hashimoto, T. Sampei, M., The Kii Channel HVDC Link in Japan. CIGRE. Paris, 2002, Paper 14-106.
* The Kii Channel HVDC system was the first HVDC project to use Gas-Insulated Switchgear (GIS) on the HVDC side
* The thyristor valves, built by
Hitachi
() is a Japanese multinational corporation, multinational Conglomerate (company), conglomerate corporation headquartered in Chiyoda, Tokyo, Japan. It is the parent company of the Hitachi Group (''Hitachi Gurūpu'') and had formed part of the Ni ...
,
Toshiba
, commonly known as Toshiba and stylized as TOSHIBA, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. Its diversified products and services include power, industrial and social infrastructure systems ...
and
Mitsubishi Electric
, established on 15 January 1921, is a Japanese multinational electronics and electrical equipment manufacturing company headquartered in Tokyo, Japan. It is one of the core companies of Mitsubishi. The products from MELCO include elevators a ...
, used 150mm diameter light triggered thyristors. At the time these were the largest thyristors ever made, and it was another 10 years thyristors of such large diameter were used again, in the Lingbao 2 and Xiangjiaba - Shanghai HVDC projects in China.
The first 50 kilometers of the transmission line run north from the Anan inverter station as an undersea cable. At Yura, there is a switching station, and from there the HVDC line runs for another 50 km as an
overhead power line
An overhead power line is a structure used in electric power transmission and distribution to transmit electrical energy across large distances. It consists of one or more uninsulated electrical cables (commonly multiples of three for three-p ...