Hedlund and for the second phase by Gunnar Ahgren. In 1977 the HVDC Vancouver Island link was supplemented by installing a second pole. This pole used thyristor valves for its static inverters and operated at a voltage of 280 kV with a rating of 370 megawatts. A new 230 kV. submarine cable for three-phase alternating current has been constructed between the Canadian mainland and Vancouver Island. This parallels the existing two HVDC lines and replaces one of two earlier 138 kV lines. In the 2005 hearings for the new 230kV circuit the HVDC systems were reported to be at the end of their service life and are not considered to be reliable. As a result of this, the first pole was shut down in 2014 and the second in 2016. Electrodes and metallic return HVDC Vancouver Island used metallic return, during monopolar operation, when current is lower than 600 A. Otherwise earth return was used. On Vancouver Island the line for metallic return is a monopolar line on wooden poles, which are used in some sections also by AC lines, running parallel to the main line of HVDC Vancouver Island. On the mainland, it uses the poles of the electrode line until a point at . After this point it runs on wooden poles together with a single-circuit three-phase AC line until . From there it runs as underground cable to Splashdown Park, where it transits at again into an overhead line, which ends at the terminal of the main line at . The electrode on the Canadian Mainland is a land electrode situated at Boundary Bay at . It is connected with Arnott Substation by an overhead pole line with two conductors. The electrode on Vancouver Island is a shore electrode in a bay at Sansum Narrows at . It is connected with Vancouver Island Terminal by an overhead line with two conductors, which is installed on wooden poles. It runs between Vancouver Island Terminal and a point northwest of Maple Bay at parallel to other power lines. See also Jordan River Dam Juan de Fuca Cable Project List of HVDC Projects Power lines connecting Vancouver Island with Canadian Mainland External links http://www.bctransco.com/regulatory/applications/Vancouver+Island+Transmission+Reinforcement+Project+CPCN+Application.htm https://www.bcuc.com/Documents/Proceedings/2005/DOC_7818_B1-1%20(Part%201%20of%202)%20VITR%20CPCN%20Application%20and%20Appx%20A-D.pdf https://web.archive.org/web/20051115122606/http://www.transmission.bpa.gov/cigresc14/Compendium/VANCOU.htm https://web.archive.org/web/20051115122606/http://www.transmission.bpa.gov/cigresc14/Compendium/Vancou+Pictures.pdf https://www.openstreetmap.org/relation/6026488#map=10/48.9396/-123.2391 https://www.bchydro.com/content/dam/BCHydro/customer-portal/documents/corporate/suppliers/transmission-system/system_operating_orders/7T23.pdf Vancouver Island HVDC transmission lines Electric power transmission systems in Canada BC Hydro Vancouver Island 1968 establishments in British Columbia Energy infrastructure completed in 1968