Jiuquan- Xiangtan (Qilian-Shaoshan)

The Jiuquan-Hunan HVDC project is an ultra-high voltage direct current (UHVDC) transmission line in China. It is an 800 kV overhead line that spans 2,383 kilometers from the Qilian converter station in Jiuquan, Gansu province, to the Shaoshan converter station in Xiangtan, Hunan province.

Technical Specifications

The project has a converter capacity of 8,000 MW and is designed to transmit large amounts of renewable energy from northwest China to the central and eastern provinces. It was China's first UHVDC project that combines large-scale wind power, solar energy, and other renewable energy sources with thermal power.

Construction and Operation

Construction of the Jiuquan-Hunan HVDC line began on September 3, 2015, following authorization and approval in May 2015. The transmission lines and towers were completed on November 24, 2016, and the converter stations were finished on December 21, 2016. After completing various tests, including low-level and high-level bipolar UHVDC tests, the system successfully passed a 168-hour continuous operation test on May 28, 2017.

Performance and Impact

Since its commissioning in 2017, the Jiuquan-Hunan HVDC line has demonstrated impressive performance. By November 24, 2023, it had delivered over 150 billion kilowatt-hours of electricity from Jiuquan to Hunan, setting a new record for cross-regional transmission. At full operation, the annual expected energy transmission from this HVDC system to Hunan is projected to reach 40 TWh, equivalent to the output of six coal-fired power plants around Changsha, meeting almost 25% of the electricity demand in Hunan province.

Environmental Benefits

The transmission of renewable energy through this line helps reduce reliance on coal-fired power plants, contributing to China's efforts to reduce carbon emissions and transition to cleaner energy sources.

Technical Challenges

The implementation of such a large-scale UHVDC project presented several technical challenges. These included managing transient voltage stability in the Hunan power grid, coordinating protection settings, and addressing issues related to broadband oscillation and transient over-voltage in hybrid power-electronics power systems (HPPESs).