All aspects of our lives are inseparable from the supply of electricity. For example, our homes, factories, schools, and hospitals all need electricity, and these electricity rely on the transmission of wires to form a dense grid. If we want more electricity, we need to build more power grids, which makes the power grid complicated, so we have only now developed a technology to make power transmission faster and more accurate, and the volume is still large, it is UHV technology . UHV technology refers to the technology of very high voltage, long-distance transmission of electric energy. The transmission voltage of China's current mature application has reached the level of AC 1000 kV and DC 800 kV.

China is a country with a large population, and the demand for electricity is also very large, but China has a large span in four directions, east, west, north and south. Energy reserves such as coal and water power are concentrated in the west and north, while most of the energy consumption demand is concentrated in the east and south. As the saying goes, far away can't quench near thirst, so the uneven distribution of energy resources and power load reminds us of a great project "West-East Power Transmission". In order to better complete the power transmission from west to east, the circuit must have the ability to pass through mountains and seas, which undoubtedly greatly increases the difficulty of construction.

During the 12th Five-Year Plan period, the State Grid Corporation of China planned a UHV pattern of "three verticals, three horizontals and one ring network" according to local conditions. Through the spatial "three vertical and three horizontal" distribution network, the regional power generated in the northwest region is input into the grid in the form of direct current, and finally transmitted to the east. Jiangsu Power Grid is the largest provincial-level receiving power grid, so it is imperative to build Huainan-Nanjing-North Zhejiang-Shanghai 1000 kV AC ring network. However, the eastern transmission line of this project faces a daunting task: UHV Cross the Yangtze River.

UHV power pipe gallery harnesses electricity across the river

In the Yangtze River section next to the Sutong Bridge, there is a special tunnel, which is the Sutong GIL integrated pipe gallery project. At 9:00 on August 21, 2018, 200 meters southwest of the Nantong Aircraft Carrier Theme Park, with the 'Excellence' The huge blade of the shield machine broke through the ground, which means that the potential 'Jiaolong' in the depths of the Yangtze River crawled forward for nearly 400 days and nights, and finally emerged triumphantly. It marks the official completion of the Sutong GIL Integrated Pipe Gallery Tunnel, the ultra-long-distance GIL with the highest voltage level, the largest transmission capacity and the most advanced technical level in the world, undertaken by the China Railway 14th Bureau, a central enterprise in Shandong. This means that China's power transmission technology has reached the world's leading level, realizing the greatest innovation in power transmission from west to east across the Yangtze River.

The Yangtze River embankment is the "guarantee line" for the property and life of people on both sides of the Yangtze River. This pipe gallery crosses the levee twice, and it is necessary to ensure the safety and smoothness of the levee. The settlement control requirements are extremely high, and the construction is difficult. Long-distance crossing of harmful gas formations contains flammable and explosive gases such as methane, which poses a very high safety risk; the thickness of the covering soil in the middle canal section of the Jiangchong River changes greatly, the water and soil pressure changes rapidly, and the parameters of the shield machine are constantly adjusted, and the construction risk is great. "In order to overcome various construction difficulties and deal with emergencies, the construction party adopted explosion-proof design throughout the tunnel construction process, including the main components of the shield machine, the entire optoelectronic system, and the tunnel lighting system. Customized." said Bin Xiwu, deputy manager of shield maintenance.

The Sutong GIL integrated pipe gallery project is the "choke point" for the operation of the UHV AC ring network in East China. The tunnel tunnel starts from Suzhou in the south and ends in Nantong in the north, with a total length of 5468.5 meters. The deepest point is 74.83 meters from the river surface. The water and soil pressure exceeds 0.9 MPa. Just like a super large electric energy storage tank, it can absorb a large amount of clean electric energy from energy bases in Inner Mongolia, Shanxi, Sichuan, etc., reduce 100 million tons of coal for power generation in the Yangtze River Delta region, reduce pollutant emissions, and promote energy revolution. At the same time, this is crucial for improving the ability of East China to receive incoming calls from outside the region, ensuring the safe operation of the power grid, and achieving the goal of ecological priority.

The Sutong GIL integrated pipe gallery started construction in August 2016 and was officially put into operation in September 2019. It is the world's first UHV 1000 kV GIL integrated river-crossing pipe gallery. It is the first time that a large-diameter shield tunnel is applied to a river-crossing GIL. Power delivery. It has overcome difficulties such as high water and soil pressure, long excavation distance, and crossing harmful gas formations. It is also the first comprehensive pipe gallery on the Yangtze River that includes municipal pipelines such as electric power, communication, and cable TV. It is called "the first corridor of the Yangtze River". Its commissioning marks the formal formation of the UHV AC double-ring network in East China, which is of great significance to supporting the regional power supply, improving the energy supply side structure, and promoting the sustainable development of the regional economy, environment and society.

There is no leakage point in the whole tunnel of Sutong GIL comprehensive pipe gallery, which is natural and won praise from all walks of life. It attracted more than 6,000 domestic and foreign experts, scholars and industry peers to observe the scene. At present, the tunnel is an industry benchmarking project with the best on-site management, the best physical quality and the fastest construction progress in China. It is also the fourth time that China Railway 14th Bureau has successfully crossed the Yangtze River after crossing the Nanjing Yangtze River Tunnel, Nanjing Metro Line 10, and Wuhan Metro Line 8, accounting for half of China's shield tunnel crossing the Yangtze River.

Provide support to help the defense of the blue sky

If the Huainan-Nanjing-Shanghai 1000 kV AC UHV ring network is a 'necklace', then our pipe gallery crossing the river is a 'diamond' that is finally embedded in this 'necklace'. ” said Yu Yuezhong, deputy general manager of Jiangsu Electric Power Engineering Consulting Co., Ltd. and project manager of the original project owner of the pipe gallery project. As one of the 12 transmission channels focused on the construction of the air pollution prevention and control action plan, the Sutong GIL integrated pipe gallery has been put into operation to form the East China UHV After the exchange of the ring network, East China can reduce 170 million tons of coal for power generation, 310 million tons of carbon dioxide, 960,000 tons of sulfur dioxide, 530,000 tons of nitrogen oxides, and 110,000 tons of soot every year, significantly improving the environmental quality of East China. Winning the blue sky defense battle provides strong support, and at the same time is of great significance to promote the economic and social development of East China, and further enhance my country's leading level and influence in the field of world power grid transmission technology and electrical equipment manufacturing.

Tian Qiang, deputy director of the Development Planning Department of Suzhou Power Supply Company, said that based on the ubiquitous concept of the Internet of Things in electric power, State Grid Jiangsu Electric Power Company will make the Sutong GIL joint ditch project a "smart" project. The project is mainly based on sharing and co-construction, and the main body is to build a world-leading shield tunnel. The Sutong GIL Gonggou Project also has two circuits of 500kV cables and municipal integrated pipeline spaces such as communications and cable TV. It will become an important part of the integration of the Yangtze River Delta and the construction of smart cities in the future.

Looking at UHV power Mount Everest

This is another major technological achievement my country has made in the field of UHV AC power transmission. Construct the Sutong GIL integrated pipe gallery project to form a UHV AC ring network in East China. The project focuses on sharing and co-construction, and the main body is to build the world's leading shield tunnel comprehensive pipe gallery. The Sutong GIL comprehensive pipe gallery project also has two circuits of 500 kV cables and municipal general pipeline space such as communication and cable TV. Industry experts said that in the future, this project will The project will become an important part of the Yangtze River Delta integration and smart city construction.

Sutong GIL UHV integrated pipe gallery is a major technological innovation in the field of underwater tunnels in China. It is a perfect combination of large-diameter shield tunneling and UHV power transmission. It has achieved many world firsts in the history of power engineering construction and tunnel shield construction. The project construction practiced the new development concept, based on independent innovation, developed and applied a number of new patented technologies, new processes and new methods, and the construction indicators reached the world-class level.

The project pioneered the use of "compact UHV GIL + large-diameter long-distance underwater tunnel" to cross the Yangtze River, representing China's international leading level in UHV power transmission research and development, electrical equipment manufacturing, deep-water tunnel construction and other fields. "Through the completion of this project, China has not only mastered the complete set of UHV GIL power transmission technology, built a long-distance tunnel GIL installation, commissioning and operation technical system, but also overcome the technical difficulties in the construction of power tunnels at the bottom of the river. , sea and other special areas have a major demonstration and leading role.

In the future, China's electricity demand will continue to increase, and regional power supply and demand will also face greater challenges. In order to ensure the healthy and stable development of China's economy and society, by 2025, Chi (Please indicate Seetao.com www.seetao.com for reprint) Seetao.com Feature Editor/Zhao E