First power lines strung on Gansu-Zhejiang ultra-high-voltage link in Zhejiang

The installation of conductor accessories on tower N5557 of the Gansu-Zhejiang ±800 kilovolt ultra-high voltage direct current transmission project was completed in Shaoxing's Shangyu district on June 14, marking the completion of the first tension stringing section for the Zhejiang segment of the Gansu-Zhejiang ultra-high-voltage direct current project.

The Gansu-Zhejiang ultra-high voltage direct current transmission project starts from Wuwei, Gansu province, and ends in Shaoxing, Zhejiang province, passing through six provincial regions including Gansu, Ningxia, Shaanxi, Henan, Anhui and Zhejiang. It spans a total length of 2,370 kilometers with a transmission capacity of 8 million kilowatts. It is China's first full-capacity ultra-high voltage flexible DC project and a key project driving energy cooperation and green transformation between China's eastern and western regions.

The construction area of the first completed section of the Zhejiang segment spans from tower N5555 to N5560, consisting of three foundation towers and three straight-line towers with a conductor length of 2.67 km. This section crosses the 500 kV Shunming 5846 line. The construction was carried out during the power outage maintenance time of this line and the cross-over construction process was completed before the peak summer season.

"The application of various mechanized equipment in the construction of the first section of the traction line serves as a test demonstration for subsequent line operations," said Pan Weilong, the project manager of the Gansu-Zhejiang ultra-high voltage direct current transmission project. "For example, we comprehensively use visual intelligent traction equipment to form an efficient operation closed loop containing equipment intelligent linkage, precise laying of ground wire and real-time data monitoring".

Due to factors such as power outage periods, terrain and bad weather, the construction of the line in this operation was tight on time and challenging. The construction personnel of Zhejiang Power Transmission Company overcame challenges such as personnel organization, site layout and equipment handling, and strictly implemented safety control measures, arranged construction plans reasonably and ensured the smooth progress of construction. Since the start of the project, the project team has promoted full-process mechanized construction using a series of mechanized construction methods, such as ground arm pole clamping, new hydraulic wire laying racks to improve construction efficiency, and introduced the concept of green construction to implement multiple measures to create an environmentally friendly project.

The Shaoxing engineering section passes through Zhuji city, Keqiao district and Shangyu district, involving 19 townships and streets. State Grid Shaoxing Power Supply Company, in conjunction with local governments, established a "district-town dual-level leadership group" collaborative mechanism, which involved conducting a large number of on-site surveys, optimizing project demonstrations, and coordinating optimization meetings to effectively ensure the efficient progress of this project. Considering the coordinated promotion of transmission projects, the province has taken the lead in obtaining route feasibility financing and agreement opinions. The route has started early with pre-work such as topographic surveys and forest land investigations, striving to advance forest land use and planning permits in parallel, and reducing the difficulty and cost of multi-party coordination. For land use approval, personnel worked out an approval mechanism of "preliminary review and subsequent supplementation". They completed land acquisition one month before approval, opened for the first time a three-level green channel of "province-city-county," and completed the agricultural land conversion approval work in advance.

The Gansu-Zhejiang ultra-high voltage direct current transmission project will be able to transmit more than 36 billion kilowatt-hours of electricity to Zhejiang annually. This project practices a new energy supply model of multi-energy complementarity, intensive development, large-scale transmission and wide-ranging consumption. It is replacing the consumption of 6.4 million metric tons of coal, reducing carbon dioxide emissions by 17 million tons, and has significant energy-saving and emission reduction benefits. At the same time, the project drives investments exceeding 80 billion yuan ($11.1 billion), can directly drive the development of the upstream and downstream industrial chains in coordination, provide over 24,000 job positions, and has enormous comprehensive economic and social benefits.