In the past 40 years of reform and opening up, under the continuous promotion of economic and social development and scientific and technological progress, an AC-DC interconnected power grid with UHV as the backbone network and strong intelligence has gradually formed, providing power security, optimizing resources and supporting green development. Other aspects have played a huge role.
AC/DC interconnection and large power grid formation
Efficiently optimize resource allocation nationwide
State Grid Co., Ltd. has accumulatively built the "Eight Crossing and Ten Straight" UHV transmission project, which has fundamentally reversed China's long-term dependence on coal transportation and partial self-balanced power development, significantly improving the level of China's power grid technology and equipment manufacturing. A major leap from global success to manufacturing, from manufacturing to China.
On September 3, the National Energy Administration issued a notice to incorporate the “five-crossing and five-straight” UHV project into the national plan; on September 7, the “Notice on Accelerating the Planning and Construction of a Batch of Key Projects for Power Transmission and Transformation” was issued, clearly Listed 9 key projects of transmission and distribution that need to be accelerated, such as the Qinghai-Henan UHV DC project and the North Shaanxi-Hebei UHV DC project.
The introduction of a number of policies means that UHV has ushered in another new construction peak.
As early as the beginning of the 21st century, the nation's power supply is facing a continuing shortage. In 2003, the country’s “re-issue and light supply” situation was serious, and the development of the power grid could not meet the needs of economic development. The natural endowment of power demand and reverse distribution of energy resources has made the country face a power shortage.
In 2004, State Grid Corporation of China proposed to build UHV, give full play to its advantages of long-distance and large-capacity transmission, and connect various large-scale energy bases in the northwest with the main load centers in the central and eastern regions to optimize energy resources on a large scale. The Jindongnan-Nanyang-Jingmen 1000 kV UHV AC pilot demonstration project started in 2006 and was completed in January 2009. Since then, thermal power in North China can be sent to Central China. During the flood season, hydropower in Central China can be sent to North China. The energy interdependence is significant.
"To achieve high-quality development of the power grid, we must conform to the national conditions and the law of power grid development, and take the path of scientific development. The core is to accelerate the construction of a strong smart grid with UHV as the backbone network and coordinated development of all levels of power grids." Director of State Grid Co., Ltd. Shu Yinyu, secretary of the party group, said at the fourth quarter work conference of the State Grid Corporation of China in 2018 that in recent years, State Grid Co., Ltd. comprehensively conquered the core technology of UHV and accumulated the “Eight Crossing and Ten Straight” UHV project, which has fundamentally reversed China’s long-term Since then, it has relied too much on coal transportation and partial self-balanced power development methods, making UHV a “golden business card” that reflects China’s technological and economic strength.
In July 2010, the Xiangjiaba-Shanghai ±800 kV UHV DC project was completed and put into operation, marking the era of China's full access to the UHV AC-DC hybrid power grid. In the summer of that year, the East China region experienced continuous high temperatures, and the number of high-temperature days at 35 degrees Celsius and above in Shanghai reached 30 days. This UHV will send clean water and electricity to the East China region, providing a strong support for ensuring Shanghai's smooth consumption of electricity peaks.
“UHV transmission is like a 'electric high-speed road', which has the characteristics of large transmission capacity, long transmission distance, wide coverage, low energy consumption and small land occupation.” Academician of Chinese Academy of Engineering, Dean of China Electric Power Research Institute Guo Jianbo said that with the comprehensive application and application of UHV AC and DC transmission technology, the power grid is not only a traditional power transmission carrier, but also a powerful energy conversion, efficient configuration and interactive service platform, which can meet the diversified needs of customers and achieve security. Efficient and clean energy development goals.
The reporter learned that as of the end of 2017, the UHV transmission channel has accumulated more than 900 billion kWh of electricity. At present, a number of key projects such as Jinshang-Xiong, Jidong-Shandong UHV DC have been included in the national plan, and State Grid Co., Ltd. will also strive to approve Zhangbei-Xiong, Nanyang-Zumadian exchange and Qinghai-Henan during the year. , "Shaanbei - Hubei, Yazhong - Jiangxi DC" and other "two cross three straight" UHV project, to help the West to East, North Power Transmission, continue to optimize the allocation of resources across the country.
UHV technology innovation upgrades make power supply safer and more reliable
The continuous upgrading of UHV grid technology has promoted the development of China's equipment manufacturing industry. State Grid Co., Ltd. also successfully won the bid for the first and second phases of the UHV DC transmission of the beautiful mountain water in Brazil, and realized the “going out” of the UHV technology, equipment, engineering general contracting and production operation.
On August 28th, on a flat land between the hills of Shanshuyuan Village, Gaoleshan Town, Xianfeng County, Hubei Province, more than 400 electrical installers were scattered on their respective working surfaces, and the installation of converter stations was in full swing.
Here is the main transformer area of the south channel converter station of the back-to-back network project of the Yi-Eu. "The flexible DC transmission project with the highest voltage level and the largest transmission capacity in the world will expand the scale of Sichuan hydropower delivery during the flood season and guarantee the acceptance of the Three Gorges Power in Chongqing during the dry season, which will effectively improve the energy consumption structure and atmospheric environment quality in the eastern and central regions." Kong Wei, senior engineer of DC Engineering Construction Department of Power Grid Co., Ltd. introduced.
“The traditional power grid is an AC transmission system, like a river. The fluctuation of the power grid is like the water in the river.” Zhao Xiongguang, a power grid planning expert at the State Grid Hubei Electric Power Company Economic and Technological Research Institute, said that after using flexible DC transmission and back-to-back networking technology, Adding a dam to the river not only reduces water fluctuations, but also controls water flow based on upstream and downstream demand for the dam. At the same time, the project can isolate the faults of the Southwest Power Grid and the Central China Power Grid, and realize the “going to be a jade”.
Today, the continuously innovative UHV transmission technology has been widely used in various UHV key projects.
Changji-Guquan ±1100 kV UHV DC transmission project has achieved many “world firsts” in terms of scale and technical level, and also achieved more than 100% in quality; Qinghai-Henan UHV transmission project relies entirely on clean energy The independent power supply of self-complementing capacity will be the first UHV channel built for clean energy delivery in the country and the world, and it is expected to achieve a breakthrough in large-scale renewable energy transmission over long distances; the world's first UHV Crossing the Yangtze River Integrated Pipe Gallery Tunnel - "Sutong GIL Integrated Pipe Gallery" has been officially completed, and is known as "a pioneering work in the history of electric power construction."
“The main channel of the Yangtze River runs more than 3,000 large vessels every day. It is most feasible to cross the river by tunnel.” The relevant person in charge of the State Grid Jiangsu Power Company said that compared with conventional cables, GIL has large transmission capacity, low loss and personal safety. High efficiency and high operational reliability, especially suitable for supplementary transmission technology in the case of overhead transmission mode or limited power transmission.
At the same time, the continuous upgrading of UHV grid technology has effectively promoted the upstream and downstream industries such as power supply, electrical equipment, energy-using equipment and raw materials, and promoted the transformation and upgrading of the equipment manufacturing industry. According to estimates, during the "13th Five-Year Plan" period, the total investment in power grid projects including UHV projects was 2.38 trillion yuan, driving power investment 3 trillion yuan, totaling about 5.4 trillion yuan, and the average annual GDP growth exceeded 0.8. percentage point.
UHV technology has not only blossomed everywhere in the country, but also has left the country. With the UHV transmission technology with independent intellectual property rights, State Grid Co., Ltd. successfully won the bid for the first and second phases of the beautiful high-voltage DC transmission of Brazil's beautiful mountain water, and realized the complete set of UHV technology, equipment, engineering general contracting and production operation in China. Go out."
Shu Yinyu said that in the future, for the development of UHV technology, we must focus on breaking the bottleneck that restricts the role of UHV engineering. "Structural contradictions on the current UHV grid's 'strong and weak cross-connect', and high-energy high-capacity access and power New applications such as the widespread use of electronic equipment, systematic research, optimization of DC drop point and access system, strengthen the electrical connection between the transmitter and the main network, improve the collection capacity of the grid, and solve problems such as terminal voltage support and tidal evacuation."
From manufacturing in China to creating in China, UHV AC and DC grids complement each other and complement each other. The level of intelligence is continuously improved, which will further serve economic and social development, ensure power supply, and promote energy transformation. The reporter learned that at present, State Grid Co., Ltd. is further promoting UHV AC GIL technology, researching and developing higher voltage level ±1100 kV UHV DC transmission technology; will start the construction of Huazhong UHV ring network, optimize and improve the receiving end 500 kV grid The structure solves the problems of heavy overload of 500 kV important section, insufficient transmission capacity and excessive short-circuit current, and improves the transmission efficiency of UHV channel, providing people with safer and more reliable power supply.
Promote the construction of UHV delivery channels to help win the "Blue Sky Defence War"
The State Grid has 8 UHV AC-DC projects included in the National Air Pollution Prevention and Control Action Plan. According to calculations, these 8 transmission lines plus Jiuquan-Hunan, Zalut-Qingzhou two UHV DC projects can reduce coal consumption per year. 180 million tons, 320 million tons of carbon dioxide emissions, 880,000 tons of sulfur dioxide, 940,000 tons of nitrogen oxides.
“Do you feel that this year’s smog days are really getting less?” Winter is coming, and intuitive feelings like this have been repeatedly mentioned.
“It’s good to be gas, electricity is electricity, use clean energy as much as possible, and speed up the proportion of clean heating.” This is the important point made by General Secretary Xi Jinping at the 14th meeting of the Central Financial and Economic Leading Group on December 21, 2016. Instructions. In fact, last winter, smog has begun to decrease rapidly at a rate visible to the naked eye. In November 2017, the average number of excellent days in 338 prefecture-level cities and above was 79.2%, an increase of 6.3 percentage points year-on-year. Among them, the air quality in the Beijing-Tianjin-Hebei region improved significantly, and the average number of days in November in the 13 cities was 68.5%.
In September 2013, the State Council issued the “Action Plan for Air Pollution Prevention and Control”, proposing to speed up the adjustment of the energy structure, comprehensively eliminate and replace the traditional energy use modes of inefficient and heavy pollution, and reduce the heavy pollution weather by a large period of five years. In 2014, in order to implement the Action Plan for Air Pollution Prevention and Control issued by the State Council, the Notice of the National Energy Administration on Accelerating the Construction of 12 Key Transmission Channels for the Action Plan for Prevention and Control of Air Pollution Prevention was released. The 12 lines connect the Beijing-Tianjin-Hebei and Yangtze River Delta regions, and the other side connects the energy base, forming a clean energy transmission map from north to south and from west to east.
At the beginning, end and along the route, these energy transmission channels are subtly changing life. On December 25, 2017, the UHV AC-DC project of the National Air Pollution Prevention and Control Action Plan was completed. Tianjin is the passing point of the Ximeng-Shandong UHV AC project and the departure point of the Mengxi-Tianjin Nante high-voltage exchange project. Thanks to “Mounting in Tianjin”, Tianjin can save 9 million tons of coal consumption, 17.5 million tons of carbon dioxide, 44,000 tons of sulfur dioxide and 46,000 tons of nitrogen oxides. In Zhejiang, a few miles away from Tianjin, the Ningdong-Zhejiang UHV DC project has also been put into operation. The receiving station Shaoxing converter station has a total input of 23.928 billion kWh, which is equivalent to saving 7.34 million tons of coal-burning and reducing the carbon dioxide emissions by 20,338,800 tons.
The transmission channel was included in the air pollution prevention action plan, which also promoted the clean construction of local coal power plants. Northern Weijiayu Coal and Electricity Co., Ltd. is the supporting power plant of Mengxi-Tianjin Nante High Pressure Project. Cui Yanbin, deputy general manager of the company, told the reporter that two 660 MW units of Weijiatun Coal and Electricity Company are now synthesizing desulfurization and denitration system and electricity. Bag dust removal, to meet the national ultra-clean emission standards; industrial wastewater internal treatment recycling, to achieve zero emissions; ash, slag and other solid pollutants can be paved, can be planted, very environmentally friendly.
The construction of key transmission channels for air pollution prevention and control is also of great significance for improving the utilization rate of renewable energy such as wind energy. The reporter learned that State Grid Co., Ltd. strengthened priority dispatching of wind power, promoted wind power heating and electric energy replacement, adopted various measures to promote new energy power generation and grid connection, and strengthened unified planning and improvement in accordance with the development idea of “building large bases and integrating into large power grids”. Supporting policies to accelerate the construction of UHV trans-regional transmission channels and peaking power supply, expand the wind power consumption market, and ensure the realization of China's wind power development goals.
Under the background of ecological civilization and beautiful China construction, the 12 key transmission channels of the National Air Pollution Prevention and Control Action Plan shoulder the important mission of promoting energy transformation and upgrading and building a beautiful China. The reporter learned that the State Grid has eight UHV AC-DC projects incorporated into the National Air Pollution Prevention and Control Action Plan. According to calculations, the eight UHV AC-DC projects plus Jiuquan-Hunan, Zalut-Qingzhou two UHV DC projects. It can reduce coal consumption by 180 million tons per year, reduce carbon dioxide emissions by 320 million tons, sulfur dioxide by 880,000 tons, and nitrogen oxides by 940,000 tons. It will significantly improve the environmental quality of the eastern and central regions and help win the "blue sky defense war."
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