Major crossing construction completed for Zhejiang section of Gansu-Zhejiang ultra-high voltage project
The Zhejiang section of the ±800-kilovolt ultra-high voltage direct current (UHVDC) transmission project from Gansu to Zhejiang successfully crossed the Cao'e River, G1522 Changtai Expressway, G104 National Highway, and multiple power lines in Shangyu, Shaoxing, Zhejiang province on Nov 28. This phase involved five transmission towers (N5560 to N5564), spanning a total length of 1.91 kilometers. The construction, which traversed both major transportation arteries and a wide river, demanded extremely high precision in conductor installation, sag control, and construction organization.
[Photo provided to chinadaily.com.cn]
The Gansu-Zhejiang ±800 kV UHVDC project is a key initiative under China's national "West-East Electricity Transfer" strategy. It is the world's first flexible DC ultra-high voltage transmission project and China's first full-capacity UHV flexible DC project. It holds significant importance for promoting the outward transmission of clean energy from large-scale base projects in the western "Desert-Gobi-Wilderness" areas and alleviating power supply and demand pressures in the East China region. The Zhejiang section of the line spans 219.16 kilometers and involves the construction of 456 new towers. It has now entered the full-scale conductor installation phase.
To overcome the challenges of the crossings, the project team fully implemented mechanized and intelligent construction methods, introducing multiple types of advanced equipment and technology. The site utilized visual intelligent tensioning equipment, enabling centralized control of tensioning devices and real-time interaction of construction data. This ensured precise control throughout the conductor installation process, effectively reducing safety risks and improving installation efficiency. Simultaneously, the team employed unmanned aerial vehicle sag surveying technology, using 3D modeling to determine the lowest sag points and sag values of the conductors, accurately verifying safe distances from obstacles below and significantly reducing human observation errors. Furthermore, tension sensors were added at the attachment points to compare the internal tension of the conductors with the designed standard sag values in real-time, quickly determining the standard attachment positions and further ensuring construction precision and line installation quality.
[Photo provided to chinadaily.com.cn]
"Relying on the visual intelligent tensioning equipment, we regulated the conductor tension in real-time to ensure the conductors maintained a safe distance from obstacles below while crossing the Cao'e River, the expressway, and the national highway," said Pan Weilong, the on-site construction manager. "This enhanced construction efficiency while ensuring safety."
To ensure everything went smoothly, State Grid Zhejiang Electric Power Company actively advanced local coordination efforts for the UHV project. They engaged with management departments such as natural resources and planning transportation, as well as pipeline units along the route, efficiently obtaining all necessary compliance permits before construction began. Concurrently, they coordinated with professionals to conduct detailed surveys of the environment around the crossing points. Over 10 route scheme demonstrations and seven route optimizations were conducted, followed by multiple rounds of ecological assessments, ultimately selecting this optimal path, which laid a solid foundation for the project's rapid advancement.
The project is a vital component of China's national "West-East Electricity Transfer" energy strategy and a key measure for ensuring Zhejiang's medium- and long-term energy security. Upon commissioning, the project will effectively enhance the clean energy supply capacity of the Zhejiang power grid, optimize the energy structure, ensure reliable power supply and stable prices, and inject robust green momentum into the high-quality economic and social development of the region.
