Electric power transmission through interconnectors using high-voltage direct-current (HVDC) involves usually two converter stations and a transmission line. Generally overhead lines are used, but an important class of HVDC projects use submarine power cables. A back-to-back station has no transmission line and joins two separate AC grids at a single point. Historical HVDC systems used the Thury system of motor-generators but these have all been made obsolete by later developments such as mercury-arc valves (now also obsolete), thyristors, and IGBT power transistors.
Legend Converter technology: Thury = Series-connected generators as designed by René Thury Merc = Mercury-arc valve rectifier and inverter Thyr = Thyristor rectifier and inverter IGBT = Insulated gate bipolar transistor BIGT = Bi-mode insulated gate transistor IEGT = Injection enhanced gate transistor
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Africa
Converterstation 1 Converterstation 2
Type Remarks Cahora Bassa Mozambique - Songo South Africa - Apollo 1420 (0/1420) 533 1920 1979 Thyr First HVDC with Project up to 500kV Siemens and ABB refurb 2013–2014 Inga-Shaba Democratic Republic of the Congo - Kolwezi Democratic Republic of the Congo - Inga 1700 (0/1700) 500 560 1982 Thyr Upgraded in 2014 Supplier: ABB, General Electric Caprivi Link Namibia - Gerus Namibia - Zambezi 950 (0/950) 350 300 2010 IGBT Supplier: ABB Ethiopia–Kenya HVDC Interconnector Ethiopia - Wolayta Kenya - Suswa 1045 (0/1045) 500 2000 2022 Thyr Supplier: Siemens
Australia and Oceania
Converterstation 1 Converterstation 2
Type Remarks HVDC Inter-Island 1 New Zealand - Benmore New Zealand - Haywards 611 (40/571) 270 600 1965 Merc Built as 250 kV 600 MW link Paralleled to operate at 270 kV as positive pole with HVDC Inter-Island 2 in 1992.Partially decommissioned in 2007, fully decommissioned in August 2012.Supplier: ABB HVDC Inter-Island 2 New Zealand - Benmore New Zealand - Haywards 611 (40/571) 350 700 1992 Thyr Negative pole, operates in bipole configuration with HVDC Inter-Island 3 (previously HVDC Inter-Island 1) Restricted to 500 MW due to cable rating.Supplier: ABB Terranora interconnector (Directlink) Australia - Mullumbimby Australia - Bungalora 59 (59/0) 80 180 2000 IGBT Land cable Supplier: ABB Murraylink Australia - Red Cliffs Australia - Berri 176 (176/0) 150 200 2002 IGBT Underground XLPE cable Supplier: ABB Basslink Australia - Loy Yang Australia - George Town 370 (298/72) 400 500 2006 Thyr One of the longest HVDC cable in operation Supplier: Siemens HVDC Inter-Island 3 New Zealand - Benmore New Zealand - Haywards 611 (40/571) 350 735 2013 Thyr Positive pole, operates in bipole configuration with HVDC Inter-Island 2Supplier: Siemens Australia–ASEAN Power Link Australia - Darwin Singapore 4200 undersea 800 overland 2027 aka Sun Cable Marinus link Australia - Burnie Australia - Latrobe Valley Approximately 340 (90/250) 750 + 750 late 2020s
Asia
Converterstation 1 Converterstation 2
Type Remarks Hokkaido - Honshu Japan - Hakodate Japan - Kamikita 193 (44/149) 250 300 1979 Thyr Supplier: ABB, Hitachi, Toshiba Zhou Shan China - Ningbo China - Gao Tongge 54 (12/42) 100 50 1982 Thyr Gezhouba - Shanghai China - Gezhouba Dam China - Nan Qiao 1046 (0/1046) 500 1200 1989 Thyr Power line shares pylons of HVDC Hubei - Shanghai in most part of its track Supplier: ABB, Siemens
HVDC C&P System Refurbished by NR Electric Sileru-Barsoor India - Sileru India - Barsoor 196 (0/196) 200 100 1989 Thyr Supplier: BHEL Ekibastuz–Tambov Kazakhstan - Ekibastuz Russia - Tambov 2414 (0/2414) 750 6000 - Thyr Construction sites abandoned around 1990 owing to collapse of Soviet Union, line was never completed Rihand-Delhi India - Rihand India - Dadri 814 (0/814) 500 1500 1990 Thyr Supplier: ABB, BHEL Haenam-Cheju South Korea - Haenam South Korea - Jeju 101 (101/0) 180 300 1996 Thyr Supplier: Alstom Leyte - Luzon Philippines - Ormoc, Leyte Philippines - Naga, Camarines Sur 451 (21/430) 350 440 1998 Thyr Supplier: ABB, Marubeni HVDC C&P System Refurbished by NR Electric Chandrapur-Padghe India - Chandrapur India - Padghe 752 (0/752) 500 1500 1999 Thyr Supplier: ABB Kii Channel Japan - Anan Japan - Kihoku 100 (50/50) 250 1400 2000 Thyr Supplier: Hitachi, Toshiba, Mitsubishi Tian-Guang China - Tianshengqiao China - Beijiao 960 (0/960) 500 1800 2001 Thyr Supplier: Siemens HVDC C&P System Refurbished by NR Electric Thailand-Malaysia Thailand - Khlong Ngae Malaysia - Gurun 110 (0/110) 300 300 2001 Thyr Supplier: Siemens Shengsi China - Shengsi China - Anabasis Sizu 66.2 (63.21/2.99) 50 60 2002 Thyr Talcher-Kolar India - Talcher, Odisha India - Kolar, Karnataka 1450 (0/1450) 500 2500 2003 Thyr Supplier: Siemens Three Gorges - Changzhou China - Longquan China - Zhengping 890 (0/890) 500 3000 2003 Thyr From north bank of Three Gorges to Zhengping, 200 km from Shanghai in the East grid Supplier: ABB, Siemens. Sharing of grounding electrode at Chujiahu with HVDC Hubei-Shanghai Guizhou - Guangdong I China - Anshun, Guizhou China - Zhaoqing, Guangdong 980 (0/980) 500 3000 2004 Thyr Supplier: Siemens Three Gorges - Guangdong China - Jingzhou China - Huizhou 940 (0/940) 500 3000 2004 Thyr Supplier: ABB Three Gorges - Shanghai China - Yidu China - Shanghai 1060 (0/1060) 500 3000 2006 Thyr Supplier: ABB Guizhou - Guangdong II China - Xingren China - Shenzhen 1200 (0/1200) 500 3000 2007 Thyr Supplier: Siemens, Sharing of grounding electrode at Linwu with HVDC Yunnan - Guangdong Ballia - Bhiwadi India - Ballia India - Bhiwadi 800 (0/800) 500 2500 2010 Thyr Supplier: Siemens Baoji - Deyang China - Baoji China - Denyang 574 (0/574) 500 3000 2010 Thyr ??? Hulunbeir - Liaoning China - Hulunbeir China - Shenyang 920 (0/920) 500 3000 2010 Thyr Supplier: ABB Xiangjiaba-Shanghai China - Fulong China - Fengxia 1980 (0/1980) 800 6400 2010 Thyr Supplier: ABB Yunnan - Guangdong China - Yunnan province China - Zengcheng 1418 (0/1418) 800 5000 2010 Thyr Supplier: Siemens, Sharing of grounding electrode at Linwu with HVDC Guizhou - Guangdong II highlight: worldwide first dc 800kv hvdc application Hubei - Shanghai China - Jingmen China - Fenjing 970 (0/970) 500 3000 2011 Thyr Power line shares pylons of HVDC Gezhouba - Shanghai in most part of its track, sharing of grounding electrode at Chujiahu with HVDC Shanghai-Changzhou ??? Nanhui Wind Farm Integration China China 8.4 (8.4/0) 30 18 2011 IGBT Supplier: C-EPRI Electric Power Engineering Co., Ltd Ningdong - Shandong China - Yinchuan China - Qingdao 1335 (0/1335) 660 4000 2011 Thyr Supplier:Alstom; C-EPRI Electric Power Engineering Co., Ltd Qinghai - Tibet China - Geermu China - Lhasa 1038 (0/1038) 400 1500 2011 Thyr Powerline reaches altitudes up to 5300 m above sea level Supplier: CET, SGCC Mundra - Haryana India - Mundra India - Mohindergarh 960 (0/960) 500 2500 2012 Thyr Supplier: Siemens Dalian City Infeed China - Dalian North China - Dalian South 43 (43/0) 320 1000 2013 IGBT Jinping - Sunan China - Jinping China - Suzhou 2090 (0/2090) 800 7200 2013 Thyr Supplier: ABB, C-EPRI Electric Power Engineering Co., Ltd ACC Provided by NR Electric in Jinping Converter Station Nanao Multi-terminal VSC HVDC China - Sucheng China - Jinniu ; China - Qingao 32 (10/32) 200/100/50 2013 IEGT/IGBT SEPRI (Electric Power Research Institute, China Southern Power Grid) is technically responsible for the entire project. Multiple suppliers are involved: three different VSC HVDC valve suppliers, two different HVDC land/sea cable suppliers and three different control & protection system/equipment suppliers. world's first multi-terminal VSC HVDC transmission project , accessed in February 2014world's first multi-terminal VSC HVDC transmission project , accessed in February 2014 Nuozhadu - Guangdong China - Nuozhadu China - Jiangmen 1413 800 6400 2013 Thyr ??? Xiluodo - Guangdong China - Zhaotong China - Conghua 1286 (0/1286) 500 6400 2013 Thyr ??? Hami - Zhengzhou China-Hami China-Zhengzhou 2210 800 8000 2014 Thyr Supplier: C-EPRI Electric Power Engineering Co., Ltd HVDC C&P System Provided by NR Electric Jindo - Jeju South Korea - Jindo South Korea - Jeju 105 (105/0) 250 400 2014 Thyr Supplier: Alstom (converter stations), LS Cable and System (cables). , Alstom Press Release, 7 July 2014. Xiluodo - West Zhejiang China - Xiluodu China - Jinghua 1680 800 8000 2014 Thyr Supplier:C-EPRI Electric Power Engineering Co., Ltd ??? Zhoushan Multi-terminal DC Interconnection China - Zhoushan China - Qushan ; China - Daishan ; China - Yangshan ; China - Sijiao 134 (134/0) 400 2014 IGBT Supplier:C-EPRI Electric Power Engineering Co., Ltd HVDC C&P System Provided by NR ElectricZhoushan Multi-terminal DC Interconnection, accessed in February 2014 Humeng - Shandong China China 800 6400 2015 Thyr ??? Irkutsk - Beijing Russia - Irkutsk China - Beijing 800 6400 2015 Thyr ??? Champa-Kurukshetra India - Champa India - Kurukshetra 1365 (0/1365) 800 2016 Thyr 2 Bipoles. Supplier: Alstom Goupitan - Guangdong China China 3000 2016 Thyr ??? Jinsha River II - East China China China 800 6400 2016 Thyr ??? North-East Agra India - Agra India - Biswanath 1728 (0/1728) 800 6000 2016 Thyr Will supply electricity to serve 90 million people Bipole Ultra high voltage, multiterminal (intermediate converter station at Alipurdauar ) Supplier: ABB New HVDC Hokkaido-Honshu Japan - Imabetsu Japan - Hokuto 122 (24/98) 250 300 2019 IGBT suppliers: Toshiba Matiari to Lahore Transmission Line Project Pakistan - Matiari, Sindh Pakistan - Lahore, Punjab 878 660 4000 2021 Thyr ±660 kV Bipole HVDC with Converter/ Grounding Electrode Stations Inner Mongolia - Linyi China - Shizhustan China - Linyi 800 6400 2017 Thyr ??? Jiuquan- Xiangtan China - Qiaowan China - Xiangtan 800 6400 2017 Thyr Supplier:C-EPRI Electric Power Engineering Co., Ltd HVDC C&P System Provided by NR Electric ??? North Shanxi - Nanjing China - North Shanxi China - Nanjing 2017 Thyr ??? Northwest Yunnan - Guangdong China - Xinsong China - Dongfang 1953 800 5000 2018 Thyr ??? Xilin Hot - Taizhou China - Xilin Hot China - Taizhou 800 10000 2017 Thyr ??? Yinchuan - Zhuji China - Yinchuan China - Zhuji 800 6400 2017 Thyr HVDC C&P System Provided by NR Electric ??? Dianxibei - Guangdong China-Lijiang China-Zhengzhen 1928/0 800 5000 2017 Thyr Supplier: C-EPRI Electric Power Engineering Co., Ltd ??? Jinsha River II - Fujian China China 800 6400 2018 Thyr ??? Humeng - Liaoning China China 800 6400 2018 Thyr ??? Rudong Offshore Wind Connector China - Jiangsu Rudong China - Jiangsu Rudong Platform 100 (100/0) 400 1100 2022 IGBT Suppliers: XJ and RXHK for valve, ZTT Cable Sheyang Offshore Wind Connector China - Jiangsu Sheyang China - Jiangsu Sheyang Platform 83 (83/0) 250 1100 2022 IGBT Zhangbei DC Grid Project China - Beijing China - Zhangbei China - Fengning China - Kangbao 495 (0/495) 500 3000/3000/1500/1500 2021 IGBT Four terminal DC Grid Suppliers: NR Electric, others Wudongde multi-terminal UHVDC demonstration project China - Yunnan China - Guangxi China - Guangdong 1489 (0/1489) 800 8000/3000/5000 2021 Thyr/IGBT Three terminal Hybrid DC system, Yunnan (Thyristor), Guangdong and Guangxi (IGBT) Raigarh-Pugalur India - Raigarh India - Pugalur India - Thrissur 1830 800 6000 2019 Thyr Supplier: ABB; One of the World's biggest Multi-terminal HVDC system with Ultra High Voltage DC Transmission system (UHVDC) CASA-1000 Tajikistan - Sangtuda Pakistan - Nowshera 750 500 1300 2025 Thyr ±500 kV Bipole HVDC with Converter Stations India–Sri Lanka HVDC InterconnectionMadurai - IndiaAnurathapura - Sri Lanka285500/10002030ThyrAndaman HVDC ConnectionParadip - IndiaPort Blair - India1160250/1252030IGBTone of the world's longest deep-sea UG cable HVDC system
Europe
Converterstation 1 Converterstation 2
Type Remarks Miesbach-Munich Power Transmission Germany - Miesbach Germany - Munich 58 (0/58) 2 0.0025 1882 Single machine Demonstration facility