The Qinghai-Henan ultra-high-voltage direct current (UHVDC) is a 1587km-long 800kV DC line to transmit renewable energy from the Qingzang Highland of the Tibetan Plateau to Central China.
It is claimed to be one of the world’s first UHVDC lines for transmitting renewable power over a long distance. The Qinghai-Henan line is also considered to be one of the highest-altitude transmission projects in the world.
Owned and operated by state-owned State Grid Corporation of China (SGCC), the UHVDC line is one of the key projects of China’s West-East Electricity Transmission initiative. The Qinghai-Henan is intended to deliver up to 8GW of clean energy, including solar and wind power, from the Qinghai-Tibet Plateau in south-western China.
Construction on the £2.53bn ($3.18bn) transmission project was started in November 2018. The project commenced partial operations after it was energised in June 2020, while the full-scale operations expected by December 2020.
The Qinghai-Henan UHVDC system is capable of transmitting 40TWh of clean power annually to meet the electricity needs of approximately eight million people while reducing CO2 emissions by approximately 30 million tonnes (Mt) a year.
The Qinghai-Henan UHVDC power transmission line originates in Hainan Tibetan Autonomous County in the Qinghai Province of China.
The overhead transmission line passes through four provinces, including Qinghai, Gansu, Shaanxi, and Henan to terminate in Zhumadian City, Henan
It passes through the Qinghai-Tibet Plateau, the uninhabited zone in Gannan, and the hinterland of the Qinling Mountains. It runs for approximately 439km in the Gansu province and approximately 518km through the Qinling Mountains in Shaanxi province.
The highest transmission lines of the Qinghai-Henan UHVDC transmission system are located at an elevation of 4,300m while its highest converter station is located at an elevation of 2,900m.
Qinghai-Henan UHVDC transmission project involves two converter stations, one each at Hainan and Zhumadian. The Hainan converter station operates as a rectifier station, while the Zhumadian station functions as an inverter station.
The Hainan converter station located at an altitude of 2,880m, at Taratan, in Republic County, Hainan. It consists of 28 units of converter transformers and six units of 750kV AC transformers at the high and low ends of the station. A total of 12 low-end converter transformers were put into operation in July 2020.
The other components for the power transmission project include two 12-pulse converters, converter valves, valve cooling system, DC protection and control, current transformer, DC voltage divider, tank circuit breaker, phasor measurement, AC protection, stability control system, grounding electrode detection system, and fire automation system.
NR Electric was contracted by SGCC for the supply of core electrical equipment.
Baoding Tianwei Baobian Electric Company (BTW) was contracted by SGCC for the supply of converter transformers.
ABB was contracted for the supply of HVDC transformers and related high-voltage equipment.
Gansu Transmission and Transfer Engineering Company managed and constructed the Gansu corridor of the Qinghai-Henan UHVDC link.
Sun. King Electronics was contracted for semi-conductor and ancillary equipment, while Sungow supplied inverters for the Qinghai-Henan power transmission project.
Zhengzhou Cathay Electric Equipment Company was contracted for glass insulator, overhead line fittings, and cable trench, while Jucro Electric Company supplied the electric vacuum circuit breakers for the Qinghai-Henan UHVDC project.