HVDC Vancouver Island

The HVDC Vancouver Island is the name for HVDC interconnection between the Vancouver Island Terminal (VIT) near North Cowichan, British Columbia on Vancouver Island at 48°49′39″N 123°42′55″W / 48.8275°N 123.71528°W / 48.8275; -123.71528 (Vancouver Island Terminal ( North Cowichan Static Inverter Plant)) and the Arnott Substation (ARN) near Delta, British Columbia at 49°5′31″N 123°2′31″W / 49.09194°N 123.04194°W / 49.09194; -123.04194 (Arnott Substation ( Delta Static Inverter Plant)) on the Canadian mainland, which went into operation in 1968 and was extended in 1977. HVDC Vancouver Island consists of three overhead line sections with a total length of 42 kilometres and two submarine cable sections with a length of 33 kilometres.

After its departure of Arnott Substation the overhead power line on the mainland split at 49°3′38″N 123°4′30″W / 49.06056°N 123.075°W / 49.06056; -123.075 (Powerline Branch) into two branches, one running to a terminal at 49°3′6″N 123°7′22″W / 49.05167°N 123.12278°W / 49.05167; -123.12278 (Mainland Cable Terminal 1) and the other running to a terminal at 49°1′40″N 123°6′1″W / 49.02778°N 123.10028°W / 49.02778; -123.10028 (Mainland Cable Terminal 2), where the first submarine cable section begins. At 48°55′07″N 123°24′15″W / 48.91861°N 123.40417°W / 48.91861; -123.40417 (Galiano Island Cable Terminal East), the first submarine cable sections ends and a short overhead line section running southwestly across Galiano Island starts. The overhead line leaves Galiano Island south of Montague Harbour in a 880 metres long span, which starts at 48°52′51″N 123°23′21″W / 48.88083°N 123.38917°W / 48.88083; -123.38917 (Galiano Island-Parker Island Span East End) and ends on Parker Island at 48°52′48″N 123°24′04″W / 48.88°N 123.40111°W / 48.88; -123.40111 (Galiano Island-Parker Island Span West End). A bit westward on Parker Island at 48°52′45″N 123°24′9″W / 48.87917°N 123.4025°W / 48.87917; -123.4025 (Parker Island Cable Terminal) the overhead line ends and the second submarine cable section begins. At 48°51′2″N 123°25′31″W / 48.85056°N 123.42528°W / 48.85056; -123.42528 (Salt Spring Island Cable Terminal) the cable reaches Salt Spring Island and the third overhead line section starts. It crosses Salt Spring Island westsouthwestly. North of Maxwell Point at 48°49′54″N 123°33′50″W / 48.83167°N 123.56389°W / 48.83167; -123.56389 (Sansum Narrows DC Powerline Span East End) and Arbutus Point at 48°49′40″N 123°35′21″W / 48.82778°N 123.58917°W / 48.82778; -123.58917 (Sansum Narrows DC Powerline Span West End) the overhead line crosses in a 1900 metres long span Sansum Narrows, the strait between Salt Spring Island and Vancouver Island. After this span the overhead line runs westward to Vancouver Island Terminal.

In 1968 the first pole of the HVDC Vancouver Island went into service. Its static inverters use mercury vapor electric rectifiers. The maximum transmission rate of this pole is 312 megawatts. Its transmission voltage is 260 kV. In 1977 the HVDC Vancouver Island was supplemented by installing a second pole. This pole uses thyristor valves in its static inverters and can transfer at an operating voltage of 280 kV with a maximum power of 370 megawatts. Currently a submarine cable for three-phase alternating current is being constructed between the Canadian mainland and Vancouver Island, that will replace the HVDC line.