Gansu–Zhejiang ±800 kV UHVDC Transmission Project (Gansu Section) Completes Pilot Tower Erection

The pilot tower erection for the Gansu–Zhejiang ±800 kV Ultra-High Voltage Direct Current (UHVDC) Transmission Project (Gansu Section) was recently conducted simultaneously at Tower No. N0011 in Minqin County, Wuwei, and Tower No. N1055 in Jingning County, Pingliang, marking the official start of full-scale tower erection in the Gansu section.

Tower Erection Site of the Gansu–Zhejiang ±800 kV UHVDC Transmission Project (Gansu Section, Lot 3)

Photo by Ma Fuyuan

According to reports, approximately 24% of the tower foundations in the Gansu Section are located in the mobile sand dunes of the Tengger Desert, where the geological conditions are characterized by loose soil structure, low load-bearing capacity, high erosion susceptibility, and significant temperature variations. To address these challenges, the construction team is using innovative techniques independently developed by State Grid Gansu Electric Power Company, such as shallow-buried gravity anchors and inclined cable anchor drilling, to significantly enhance operational efficiency and provide a model for applying new techniques in future UHVDC projects.

"The desert terrain is highly dynamic, and shallow-buried gravity anchors are better suited to such conditions than traditional anchors," said Pan Jie, Deputy Manager of the Construction Project Department for Lot 1 of the Gansu Section of the Gansu–Zhejiang Power Transmission Project. "The inclined anchor drill allows the rods to rapidly penetrate the sand layers, while custom-designed blades securely 'grip' the sand. These anchors can bear both vertical loads and substantial angled tensile forces. Four anchor drills can be installed in just 20 minutes through mechanized operations. The screwing process causes minimal disturbance to the sand, greatly improving anchor stability and resolving a major challenge in desert construction—excavating anchor pits."

Tower Erection Site of the Gansu–Zhejiang ±800 kV UHVDC Transmission Project (Gansu Section, Lot 1)

Photo by Jin Hao

The Gansu–Zhejiang Transmission Project is a key initiative under China's 14th Five-Year Plan for power development. It is the first UHVDC transmission project using flexible direct current technology at both ends. The project starts in Wuwei, Gansu Province, and ends in Shaoxing, Zhejiang Province, spanning six provinces and autonomous regions: Gansu, Ningxia, Shaanxi, Henan, Anhui, and Zhejiang. The entire transmission line covers 2,370 kilometers, including 494.25 kilometers in the Gansu section, where 957 new transmission towers will be constructed. The sending-end converter station will connect to Gansu's large-scale wind and solar power base located in the "desert-Gobi-wilderness" areas. Once in operation, the project will enable Gansu to deliver over 36 TWh of electricity to Zhejiang annually, more than 50% of which will come from green energy sources. It is expected to reduce carbon emissions by 17 million tonnes per year, further advancing the development and utilization of clean energy in Gansu—one of China's leading provinces for wind and solar power—and making a significant contribution to optimizing the national energy mix and promoting the transition to green development. (Written by Wang Xinyue, Jin Hao, and Qiang Kemao)