On December 18, the fourth UHVDC transmission project [Yazhong (Yalong River)-Jiangxi ±800 kV UHVDC Project, referred to as Yazhong Project] was successfully started at the main venue of the fourth quarter of 2019 major projects in Sichuan Province located in the State Grid Sichuan Electric Power Company. Marked by the start of the Yazhong Project, in the next four years, Sichuan will build three new UHV lines, setting off a new round of UHV construction.
Why is it called a "megaproject"?
Big, high-valued, and difficult to engineer
"The preparation for the construction of the project has been completed, and all the construction personnel will accelerate the construction to ensure that it will be put into operation in 2021." Hu Haijian, general manager of State Grid Sichuan Electric Power Company, reported at the construction site in Yanyuan County, Liangshan Prefecture. More than 2,000 construction personnel were stationed on site, engineering equipment was organized in place, and the UHV "super project" was fully launched.
The reason why Yazhong Engineering is called "super project" is, first of all, because of its large size. The Yazhong project starts from Yanyuan County, Liangshan Prefecture and ends in Fuzhou City, Jiangxi Province, passing through five provinces: Sichuan, Yunnan, Guizhou, Hunan and Jiangxi, with a total investment of 24.4 billion yuan and a transmission distance of 1,700 kilometers. In Sichuan alone, one converter station, 208 kilometers of lines, more than 1,000 towers will be erected, and 28 bridges will be built, renovated and expanded. Opening the list of units participating in the Yazhong project, the names of 43 units occupy several pages, "During peak hours, the number of project participants can reach tens of thousands. Wang Yongping, commander-in-chief of the State Grid Sichuan Electric Power UHV Engineering Construction Headquarters, said.
The "mega project" also faces serious construction challenges. Within two years, in addition to the salt source converter station, various line projects need to be completed at the same time, with huge projects and concentrated construction periods. Due to the multiple tests of mountain roads, bridges and tunnels in Liangshan Prefecture, the difficulty of transporting large items of the project is the most difficult in domestic converter stations. In order to solve the problem of transporting giant electrical equipment, it is also necessary to build a super-large arch bridge with the heaviest load tonnage in China across the Yalong River. A number of construction contents were implemented in the State Grid system for the first time, and the project safety and quality control faced great challenges.
How important is engineering to Sichuan?
Increase the capacity of inter-provincial hydropower transmission to alleviate the problem of water abandonment
Why is Yazhong Engineering so important to Sichuan? Tan Hongen, chairman of the State Grid Sichuan Electric Power Company, explained that the project has three major benefits——
First of all, it can promote the development and delivery of clean energy. The installed capacity of hydropower in Sichuan Province exceeds 76 million kilowatts, ranking first in the country. However, due to the lack of delivery channels, the problem of water abandonment during the flood period is a pain point. "After the completion of the Yazhong Project, Sichuan Power Grid will add 8 million kilowatts of inter-provincial transmission capacity and 40 billion kilowatt-hours of annual external electricity." Tan Hongen said that as a result, the transmission capacity of Sichuan Power will reach 38.6 million kilowatts, and the annual transmission of electricity will exceed 170 billion kilowatt hours.
The second advantage is to stimulate economic growth and promote economic development. It is estimated that Yazhong Engineering will invest 24.4 billion yuan, which will increase the output value of the power transmission and transformation equipment manufacturing industry by 7 billion yuan, and directly drive the investment of power supply and other related industries by about 100 billion yuan.
In addition, as a green project, after the Yazhong project is put into operation, it can reduce the annual consumption of thermal coal by 16 million tons, reduce carbon dioxide by 40 million tons, sulfur dioxide by 320,000 tons, and nitrogen oxides by 60,000 tons.
UHV enters a period of intensive construction?
Sichuan's "New Three Straight" project was launched and completed in the next four years
Sichuan is a major province for hydropower transmission, and three UHVDC transmission projects have been completed, namely the Fufeng Line (Xiangjiaba - Shanghai, put into operation in 2010), the Jinsu Line (Jinping-Sunan, put into operation in 2012), and the Binjin Line (Xiluodu Left Bank - Zhejiang Jinhua, put into operation in 2014). So far, the three UHV lines have delivered more than 700 billion kilowatt-hours of clean hydropower to Shanghai, Zhejiang and Jiangsu, equivalent to the annual power generation of about seven Three Gorges power stations.
With the start of the Yazhong project, Sichuan will set off a new round of UHV construction. "Following the three UHV projects of Fufeng, Jinsu and Binjin, State Grid has launched three new UHV projects, namely the Sichuan 'New Three Direct' Project." Li Wei, deputy commander-in-chief of the State Grid Sichuan Electric Power UHV Project Construction Headquarters, said. In addition to the Yazhong project, the "New Three Directs" project also includes two major UHVDC projects, Baihetan-Jiangsu and Baihetan-Zhejiang.
The total investment of the "New Three Directs" project is about 86 billion yuan, of which about 24.2 billion yuan is invested in Sichuan. The Baihetan-Jiangsu project starts from Butuo County, Liangshan Prefecture and ends in Changshu City, Jiangsu Province, and is scheduled to be completed and put into operation in 2022; The Baihetan-Zhejiang Project has the same path as the Baihetan-Jiangsu Project in Sichuan, and feasibility studies are currently underway, and it is planned to be completed and put into operation in 2023. After the completion of the "New Three Directs" project, the scale of Sichuan's hydropower transmission will be doubled again, greatly alleviating the problem of water abandonment during the flood season.