Ultra-High-Voltage (UHV) Power Transmission System in China
From Global Energy Monitor
Ultra high voltage (UHV) refers to power transmission technology with alternating current (AC) voltage levels of 1000 kilovolts or more and direct current (DC) of ±800 kilovolts or more, a definition by China. Other countries may have different thresholds. China commissioned the first such power transmission line in 2009. As of December 2025, 45 UHV power transmission lines were operating, of which, 21 with AC and 24 with DC.
Layout
Operating UHV transmission lines in China (by the end of 2025).
Operating 1000 kV Ultra-AC transmission lines in China (by the end of 2025).
Operating ±800 & ±1100 kV Ultra-DC transmission lines in China (by the end of 2025).
East China Ultra-AC grid and its supporting Ultra-DC lines
Central China Ultra-AC grid and its supporting Ultra-DC lines
Ultra DC and AC lines entering Shandong
North China and Shandong Ultra-AC grid and its supporting Ultra-DC lines
Technology
Abbreviations
UHVDC --特高压直流输电(ultra-high-voltage direct current)
UHVAC-- 特高压交流输电( ultra-high-voltage alternating current)
HVDC--高压直流电(High-voltage direct current)
The advantages of UHV
- large transmission capacity
- long transmission distance
- low line loss
- space saving
- Improved Efficiency: The application of ultra-high voltage technology allows an effective increase in transmission efficiency, reducing interference caused by external and internal factors. Besides, it does not require reactive compensation, unlike traditional power transmission models, which may be limited by thermal resistance problems in the high voltage cables, which affects the stability of the transmission.
- Greater Reliability and Stability: Ultra high voltage transmission is more reliable and stable, Effectively avoiding wasting energy during transmission. Even in adverse conditions, it can meet high power transmission demands, something that traditional methods cannot match.
- Costs reduction: The application of ultra-high voltage transmission technology allows a significant reduction in power transmission costs. According to data, The transmission capacity of ultra-high voltage lines is more than three times higher compared to conventional transmission lines. This means that under the same transmission conditions, ultra-high-voltage networks can reduce electricity grid costs by 90%.
- Balance in Energy Distribution: Promotion of ultra-high voltage transmission technology can achieve a balance in electric power distribution, benefiting various regions and ensuring equitable distribution of energy.
The disadvantages of UHV
- Impact on Human Health: There is a debate in the scientific community about the impact of ultra-high voltage on human health. A definitive conclusion has not yet been reached and a more complete data analysis is required.. Fortunately, Most ultra-high voltage transmission lines are located in areas far from inhabited areas., which limits direct contact with the population.
- Need for Continuous Innovation: Despite significant advances in ultra-high voltage transmission technology and its promising future in the electrical sector, it is necessary to continue innovating based on the changing demands of energy transmission. The rapid evolution of electrical technologies implies the need to research and develop products such as lightning arresters and transformers in accordance with power transmission requirements.
- Vulnerable for natural disasters and the terrorism attack, especially the DC transmission lines. ((need to add more from the debate))
- Expensive on constructing such a line.
Key Technologies and Innovations
2.4.1 UHV Transformer 特高压变压器
UHV transformer — typically referring to transformers for AC transmission at 1000 kV and above or DC transmission at ±800 kV and above — adjusts voltage levels through electromagnetic induction, enabling efficient transmission and distribution of electrical power.
UHV transformer is significantly more technically challenging than conventional transformers rated at 500 kV and below. For example, UHV transformers must withstand voltages of 1000 kV and above, far exceeding the requirements of standard transformers. Traditional ceramic insulation materials cannot meet these demands. To address this, China has independently developed specialized insulation paper, replacing the 7,000-ton ceramic insulation solutions previously used in the United States. This innovation has reduced the transformer's weight to less than 500 tons while maintaining excellent insulation performance.
2.4.2 Converter 换流阀
A converter station is a large, specialized facility that converts electricity between AC and DC, which plays a crucial role in UHVDC.
The converter valve is the core equipment in the converter station and is known as the "heart" of DC transmission. The converter valve is composed of multiple thyristors (or IGBTs) connected in series. It converts AC into DC (rectification) at the sending end (generation side) and inverts DC into AC (inversion) at the receiving end (power consumption side), ensuring that electric energy is transmitted over long distances in the form of UHV.
2.4.3 Voltage Source Converter based High Voltage Direct Current (VSC-HVDC) 柔性直流技术
VSC-HVDC is a new type of power transmission technology based on fully controllable power electronic devices, such as Insulated Gate Bipolar Transistors (IGBTs), and Voltage Source Converters (VSCs). It precisely controls the voltage magnitude and phase angle through Pulse Width Modulation (PWM), enabling independent regulation of both active power and reactive power.
Compared to Line Commutated Converter based HVDC (LCC-HVDC), VSC-HVDC allows for flexible, bidirectional power transmission without relying on the commutation support of the connected AC grid voltage, which enables it to provide stronger adaptability, achieve higher operating efficiency, and contribute to stronger grid stability.
Background
Who invented UHV?
- The former Soviet Union launched the first 907 kilometers long UHV transmission line, connecting the towns of Ekibastuz and Kokchetav in Kazakhstan in September 1985 with a voltage of 1150 kV. It was downgraded to a common 500 kV after the dismantlement of the Soviet Union in 1991.
Besides China, which countries have developed UHV transmission lines?
- India
- Japan.
- Brazil
- Italy
- UK
When did China adopt the technology?
- Since 2004, China began large scale experiment on UHV. In 2006, the first such line, Southeastern Shanxi - Nanyang - Jingmen UHV was permitted for construction and went operational in 2008.
UHV Transmission Line Network details
Four stages of UHV development in China
- 2009-2014 Mainly hydro and coal power transmission 以煤电传输开端，以水电传输为主.
- 2015-2019 In order to improve the air quality in major cities, UHV permitting and construction accelerated, aiming to replace coal use in the areas. 改善大气环境, 输电代替输煤.
- 2020-2024 Establish and strengthen UHV regional power grid 直流输电特高压线路以水电为主；建立并加强交流特高压局域电网.
- 2025- Accelerate providing access to renewable energy 为可再生能源提供通道.
Table 1: UHV projects commissioned 2009-2014
| UHV Power Tansmission Line | UHV Tansmission Line in Chinese | Other name | Capacity 额定输送容量 (MW) | Status | Transmission Distance（km） | Investment (Billion RMB） | Technology | Permitted Date | Commissioned Year | Ultimate Parent | Start Region | End Region |
| Southeastern Shanxi - Nanyang - Jingmen | 晋东南--南阳--荆门1000千瓦特高压交流实验示范工程 | 晋南荆线 | 5000 | operating | 645 | 5.887 | 1000 kV Ultra-AC | 2006-8 | 2009 | State Grid | Shanxi | Hubei |
| Xiangjiaba-Shanghai | 向家坝-上海±800千伏特高压直流输电示范工程 | 复奉直流 | 6400 | operating | 1907 | 23.274 | ±800 kV Ultra-DC | 2007-04-26 | 2010 | State Grid | Sichuan | Shanghai |
| Yunnan-Guangdong | 云南楚雄-广东惠东（云广±800千伏特高压直流输电工程） | 楚穗直流，云广直流 | 5000 | operating | 1373 | 13.2 | ±800 kV Ultra-DC | 2006 | 2010 | China Southern Power Grid | Yunnan | Guangdong |
| Jinping-Jiangsu South | 锦屏-苏南 ±800千伏特高压直流输电工程 | 锦苏直流 | 7200 | operating | 2059 | 22 | ±800 kV Ultra-DC | 2008-11 | 2012 | State Grid | Sichuan | Jiangsu |
| Anhui South- Zhejiang North- Shanghai | 皖电东送淮南-浙北-上海特高压交流输电示范工程 | 皖电东送，淮沪特高压 | 10500 | operating | 648.7 | 18.5 | 1000 kV Ultra-AC | 2012-09 | 2013 | State Grid | Anhui | Shanghai |
| Nuozhadu-Guangdong | 糯扎渡送电广东±800kV直流输电工程（云南普洱-广东江门） | 普侨直流 | 5000 | operating | 1413 | 13.3 | ±800 kV Ultra-DC | 2011-10 | 2013 | China Southern Power Grid | Yunnan | Guangdong |
| Zhejiang North-Zhejiang Middle-Zhejiang South-Fuzhou | 浙北-福州1000千伏特高压交流输变电工程 | 浙福特高压 | 6800 | operating | 603 | 18.87 | 1000 kV Ultra-AC | 2013-03 | 2014 | State Grid | Zhejiang | Fujian |
| Xiluodu-Zhejiang | 溪洛渡左岸-浙江±800千伏特高压直流输电工程 | 宾金直流, 溪浙工程 | 8000 | operating | 1680 | 23.855 | ±800 kV Ultra-DC | 2012-07 | 2014 | State Grid | Sichuan | Zhejiang |
| Hami South -- Zhengzhou | 哈密南--郑州±800千伏特高压直流输电工程 | 天中直流，哈郑直流，疆电外送第三通道 | 8000 | operating | 2192 | 23.4 | ±800 kV Ultra-DC | 2012-5 | 2014 | State Grid | Xinjiang | Henan |
Table 2: UHV projects commissioned 2015-2019
| UHV Power Tansmission Line | UHV Tansmission Line in Chinese | Other name | Capacity 额定输送容量 (MW) | Status | Transmission Distance（km） | Investment (Billion RMB） | Technology | Permitted Date | Commissioned Year | Ultimate Parent | Start Region | End Region |
| Xilingol- Shandong | 锡盟--山东1000千伏特高压交流输变电工程 | 9000 | operating | 730 | 17.8 | 1000 kV Ultra-AC | 2014-7-12 | 2016 | State Grid | Inner Mongolia | Shandong | |
| Western Mongolia- Tianjin | 蒙西-天津南1000千伏特高压交流输变电工程 | 8000 | operating | 608 | 17.5 | 1000 kV Ultra-AC | 2015-1 | 2016 | State Grid | Inner Mongolia | Tianjin | |
| Eastern Ningxia- Zhejiang | 宁东-浙江±800千伏特高压直流输电工程 (灵州-绍兴±800千伏特高压直流输电工程) | 灵绍直流 | 8000 | operating | 1720 | 23.7 | ±800 kV Ultra-DC | 2014-8-5 | 2016 | State Grid | Ningxia | Zhejiang |
| Jiuquan- Hunan | 酒泉-- 湖南+-800千伏特高压直流输电工程 | 祁韶直流，酒湖工程，陇电入湘 | 8000 | operating | 2383 | 26.2 | ±800 kV Ultra-DC | 2015-5-18 | 2017 | State Grid | Gansu | Hunan |
| Xilingol-Shengli | 胜利--锡盟特高压交流输电工程(张北-胜利特高压的一部分) | 3000 | operating | 240 | 4.956 | 1000 kV Ultra-AC | 2016-01 | 2017 | State Grid | Inner Mongolia | Inner Mongolia | |
| Yuheng- Weifang | 榆横--潍坊1000千伏特高压交流输变电工程 | 6000 | operating | 1049 | 24.2 | 1000 kV Ultra-AC | 2015-5 | 2017 | State Grid | Shaanxi | Shandong | |
| Xilingol- Jiangsu | 锡盟-泰州±800千伏特高压直流工程 | 锡泰直流 | 10000 | operating | 1619 | 26.4 | ±800 kV Ultra-DC | 2015-10-30 | 2017 | State Grid | Inner Mongolia | Jiangsu |
| Jarud- Shandong Qingzhou | 扎鲁特--山东青州±800千伏特高压直流输电工程 | 鲁固直流 | 10000 | operating | 1234 | 22.1 | ±800 kV Ultra-DC | 2016-8 | 2017 | State Grid | Inner Mongolia | Shandong |
| Northern Shanxi- Nanjing | 晋北--江苏±800千伏特高压直流输电工程 （雁门关-淮安特高压直流输电工程） | 雁淮直流 | 8000 | operating | 1119 | 16.2 | ±800 kV Ultra-DC | 2015-6-10 | 2017 | State Grid | Shanxi | Jiangsu |
| Yunnan Northwest-Guangdong | 滇西北—广东±800千伏直流输电工程（丽江—深圳±800千伏特高压直流线路） | 新东直流 | 5000 | operating | 1953 | 17 | ±800 kV Ultra-DC | 2015-12-28 | 2018 | China Southern Power Grid | Yunnan | Guangdong |
| Anhui South- Nanjing- Shanghai | 皖电东送淮南-南京-上海1000千伏特高压交流输变电项目 | 皖电东送，淮沪特高压 | 6000 | operating | 779.5 | 26.1 | 1000 kV Ultra-AC | 2014-4-21 | 2019 | State Grid | Anhui | Jiangsu |
| Xiong'an-Shijiazhuang | 雄安-石家庄1000千伏特高压交流工程 （北京西-石家庄交流特高压输变电工程） | 5300 | operating | 228 | 3.5 | 1000 kV Ultra-AC | 2017-07 | 2019 | State Grid | Hebei | Hebei | |
| Shanghai Temple- Shandong | 上海庙--山东临沂±800千伏特高压直流输电工程 | 昭沂直流 | 10000 | operating | 1238 | 22.1 | ±800 kV Ultra-DC | 2015-12 | 2019 | State Grid | Inner Mongolia | Shandong |
| Zhundong - Southern Anhui | 准东--皖南±1100千伏特高压直流输电工程 | 吉泉直流，疆电外送第四通道 | 12000 | operating | 3324 | 40.7 | ±1100 kV Ultra-DC | 2015-12-28 | 2019 | State Grid | Xinjiang | Anhui |
Table 3: UHV projects commissioned 2020-2024
| UHV Power Tansmission Line | UHV Tansmission Line in Chinese | Other name | Capacity 额定输送容量 (MW) | Status | Transmission Distance（km） | Investment (Billion RMB） | Technology | Permitted Date | Commissioned Year | Ultimate Parent | Start Region | End Region |
| Zhangbei-Xiong'an | 张北-雄安1000千伏特高压交流输变电工程 | 6000 | operating | 319 | 5.98 | 1000 kV Ultra-AC | 2018-11 | 2020 | State Grid | Hebei | Hebei | |
| Zhumadian-Nanyang | 驻马店-南阳1000千伏特高压交流输电工程 | 3100 | operating | 188.4 | 2.16 | 1000 kV Ultra-AC | 2018-12-10 | 2020 | State Grid | Henan | Henan | |
| Western Mongolia-Mid Shanxi | 蒙西-晋中1000千伏特高压交流工程 | 8000 | operating | 313 | 5.4 | 1000 kV Ultra-AC | 2018-03 | 2020 | State Grid | Inner Mongolia | Shanxi | |
| Weifang-Linyi-Zaozhuang-Heze-Shijiazhuang | 潍坊-临沂-枣庄-菏泽-石家庄1000千伏特高压交流工程 （山东-河北特高压交流环网） | 4500 | operating | 816 | 14 | 1000 kV Ultra-AC | 2017-10-31 | 2020 | State Grid | Shandong | Hebei | |
| Qinghai-Henan | 青海—河南±800千伏特高压直流输电工程 | 青豫直流 | 8000 | operating | 1587 | 22.3 | ±800 kV Ultra-DC | 2018-10 | 2020 | State Grid | Qinghai | Henan |
| Wudongde-Guangxi-Guangdong | 乌东德电站送电广东广西特高压多端柔性直流示范工程 | 昆柳龙直流 | 8000 | operating | 1452 | 24.3 | ±800 kV Ultra-DC | 2018-03 | 2020 | China Southern Power Grid | Yunnan | Guangdong |
| Nanchang-Changsha | 南昌-长沙1000千伏特高压交流输电工程 | 4000 | operating | 341 | 10.2 | 1000 kV Ultra-AC | 2020-12-22 | 2021 | State Grid | Jiangxi | Hunan | |
| North of Shaanxi-Hubei Wuhan | 陕北-湖北±800千伏特高压直流工程 | 陕武直流 | 8000 | operating | 1137 | 18.5 | ±800 kV Ultra-DC | 2019-01-01 | 2021 | State Grid | Shaanxi | Hubei |
| Yazhong-Jiangxi | 雅中-江西±800千伏特高压直流输电工程 | 雅湖直流 | 8000 | operating | 1696 | 24.4 | ±800 kV Ultra-DC | 2019-08 | 2021 | State Grid | Sichuan | Jiangxi |
| Nanyang-Jingmen-Changsha | 南阳～荆门～长沙1000kV特高压交流输变电工程 | 南荆长特高压 | 6000 | operating | 625.8 | 15.84 | 1000 kV Ultra-AC | 2021-4-1 | 2022 | State Grid | Henan | Hunan |
| Jingmen-Wuhan | 荆门—武汉1000千伏特高压交流输变电工程 | 2800 | operating | 234 | 6.5 | 1000 kV Ultra-AC | 2020-12-23 | 2022 | State Grid | Hubei | Hubei | |
| Baihetan-Jiangsu | 白鹤滩-江苏±800千伏特高压直流输电工程 | 建苏直流 | 8000 | operating | 2087 | 30.7 | ±800 kV Ultra-DC | 2020-11 | 2022 | State Grid | Sichuan | Jiangsu |
| Baihetan-Zhejiang | 白鹤滩—浙江±800千伏特高压直流输电工程 | 金塘直流，白浙工程 | 8000 | operating | 2121 | 29.9 | ±800 kV Ultra-DC | 2021-07 | 2022 | State Grid | Sichuan | Zhejiang |
| Fuzhou-Xiamen | 福州-厦门1000千伏特高压交流输电工程 | 4000 | operating | 234 | 7.1 | 1000 kV Ultra-AC | 2022-01 | 2023 | State Grid | Fujian | Fujian | |
| Zhumadian-Wuhan | 驻马店-武汉1000千伏特高压交流输电工程 | 3100 | operating | 287 | 3.8 | 1000 kV Ultra-AC | 2021-11-17 | 2023 | State Grid | Henan | Hubei | |
| Wuhan-Nanchang | 武汉—黄石—南昌1000千伏特高压交流线路工程 | 4700 | operating | 462.9 | 9.082 | 1000 kV Ultra-AC | 2022-6-27 | 2023 | State Grid | Hubei | Jiangxi | |
| Zhangbei-Shengli | 张北-胜利1000千伏特高压输电交流项目 | 4000 | operating | 366 | 6.786 | 1000 kV Ultra-AC | 2022-09-15 | 2024 | State Grid | Hebei | Inner Mongolia | |
| Sichuan-Chongqing | 川渝1000千伏特高压交流工程 | 4000 | operating | 658 | 28.6 | 1000 kV Ultra-AC | 2022-09 | 2024 | State Grid | Sichuan | Chongqing |
Table 4: UHV projects commissioned in 2025
| UHV Power Tansmission Line | UHV Tansmission Line in Chinese | Other name | Capacity 额定输送容量 (MW) | Status | Transmission Distance（km） | Investment (Billion RMB） | Technology | Permitted Date | Commissioned Year | Ultimate Parent | Start Region | End Region |
| Gansu East- Shandong | 陇东-山东特高压直流工程 | 陇电入鲁，庆东直流 | 8000 | operating | 926 | 20.2 | ±800 kV Ultra-DC | 2023-2 | 2025 | State Grid | Gansu | Shandong |
| Ningxia-Hunan | 宁夏-湖南±800千伏直流特高压外送工程 | 宁电入湘，中衡直流 | 8000 | operating | 1634 | 28.1 | ±800 kV Ultra-DC | 2023-05-24 | 2025 | State Grid | Ningxia | Hunan |
| Jinshang-Hubei | 金上（金沙江上游）--湖北±800千伏特高压直流输电工程 | 金湖特高压，金上—湖北工程 | 8000 | operating | 1784 | 33.5 | ±800 kV Ultra-DC | 2022 | 2025 | State Grid | Sichuan | Hubei |
| Hami North-Chongqing | 哈密—重庆±800千伏特高压直流输电工程 | 哈重特高压，“疆电外送”第三条直流通道，疆电入渝，坤渝直流 | 8000 | operating | 2290 | 28.6 | ±800 kV Ultra-DC | 2023-07 | 2025 | State Grid | Xinjiang | Chongqing |
Table 5: UHV projects under construction and proposed by June 2026
| UHV Power Transmission Line | UHV Tansmission Line in Chinese | Other name | Capacity 额定输送容量 (MW) | Status | Transmission Distance（km） | Investment (Billion RMB） | Technology | Permitted Date | Supporting coal (MW) | Supporting Wind+Solar+Photothermal (MW) | Start Region | End Region | Commissioned Year |
| Badan Jilin (Badain Jaran)-Sichuan (Gansu-Sichuan) | 巴丹吉林-四川±800千伏特高压直流线路工程 | 陇电入川 | 8000 | Proposed | 1460 | 24.6 | ±800 kV Ultra-DC | 4000 | 11000 | Gansu | Sichuan | ||
| Gansu-Zhejiang | 甘肃－浙江±800千伏特高压直流输电工程（陇电入浙） | 陇电入浙 | 8000 | construction | 2370 | 35.3 | ±800 kV Ultra-DC | 2024-7 | 4000 | 11200 | Gansu | Zhejiang | 15th FYP |
| Songliao-China North | 松辽~华北直流特高压输电线路 | 吉电入京 | proposed | 1000 | ±800 kV Ultra-DC | Jilin | Beijing | 2029 | |||||
| Western Mongolia-Beijing, Tianjin, Hebei | 蒙西-京津冀（库布齐-雄安）±800kV特高压直流输电线路工程 | （库布其北—沧州±800kV 特高压直流输电工程） | 8000 | construction | 699.7 | 17.18 | ±800 kV Ultra-DC | 2025-7 | 4000 | 12200 | Inner Mongolia | Hebei | |
| Kubuqi-Jiangsu | 库布齐-江苏直流特高压输电线路 | 8000 | proposed | 1793 | 64.2 | ±800 kV Ultra-DC | 2640 | 12000 | Inner Mongolia | Jiangsu | |||
| Tengri-Jiangxi | 腾格里—江西特高压直流工程 | 8000 | proposed | 2151.7 | 29.7 | ±800 kV Ultra-DC | 4000 | 12000 | Inner Mongolia | Jiangxi | |||
| Kubuqi-Shanghai | 库布齐—上海特高压直流工程 （内蒙古库布齐沙漠基地送电上海±800千伏直流工程） | 蒙电入沪 | 8000 | proposed | 1951 | ±800 kV Ultra-DC | 2640 | 12500 | Inner Mongolia | Shanghai | |||
| Qinghai Hainan-Guangdong | 青海海南清洁能源基地—广东特高压直流工程 | 青粤直流 | 8000 | proposed | 2511 | 73 | ±800 kV Ultra-DC | 2640 | 15600 | Qinghai | Guangdong | 2028 | |
| Shaanxi-Anhui | 陕西-安徽±800千伏特高压直流输电工程 | 8000 | construction | 1070 | 20.5 | ±800 kV Ultra-DC | 2024-02-22 | 4000 | 11000 | Shaanxi | Anhui | ||
| Shaanxi-Henan | 陕西-河南±800kV特高压直流输电工程 | 陕豫特高压 | 8000 | permitted | 727.5 | 19.24 | ±800 kV Ultra-DC | 2026-03 | 4000 | 11000 | Shaanxi | Henan | 2028 |
| Yantai-Weihai | 烟威特高压交流工程 | construction | 567 | 1000 kV Ultra-AC | 2025-01 | Shandong | Shandong | ||||||
| Haiyang Xin'an Nuclear Transmission Line | 海阳辛安核电1000千伏送出工程（中核 CX 送出工程） | construction | 41 | 1000 kV Ultra-AC | 2025-01 | Shandong | Shandong | ||||||
| Datong-Huailai-Tianjin South | 大同-怀来-天津南特高压交流工程 | 8000 | construction | 771.9 | 22.5 | 1000 kV Ultra-AC | 2024-09 | 4000 | 6000 | Shanxi | Tianjin | ||
| Sichuan-Chongqing Enhance Project | 川渝特高压交流加强工程 | proposed | 478.2 | 1000 kV Ultra-AC | Sichuan | Chongqing | |||||||
| Tibet Southeast-Guangdong, Hong Kong, Macao | 藏东南-粤港澳大湾区±800千伏特高压直流输电工程 | 藏玉直流，藏粤直流 | 10000 | construction | 2681.3 | 52.161 | ±800 kV Ultra-DC | 2025-06-25 | Tibet | Guangdong | |||
| Xinjiang South-Sichuan, Chongqing | 疆电（南疆）送电川渝特高压直流工程（“疆电入川”,“疆电外送”直流四通道工程） | 8000 | Proposed | 1998.7 | 33.2 | ±800 kV Ultra-DC | 3960 | 12500 | Xinjiang | Sichuan | |||
| Zhejiang 1000 kv Network | 浙江 1000kv交流联网 | permitted | 1000 kV Ultra-AC | 2025-12-11 | Zhejiang | Zhejiang | 2029 |
