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The world's largest Liangshan hydropower "Big Mac" has come | I'll build the big country project
The world's largest Liangshan hydropower "Big Mac" has come | I'll build the big country project
At 26 ° 91 'north latitude and 102 ° 93' east longitude, on the Jinsha River Canyon at the junction of Ningnan County, Sichuan Province and Qiaojia County, Yunnan Province, a hydropower station with the largest installed scale in the world has sprung up-the Baihetan Hydropower Station on the Jinsha River.
On the Jinsha River, steep walls are overgrown and the river is surging. The huge gap has led countless generations of hydropower people to find opportunities for China's hydropower development here. From the origin of Geladandong Snow Mountain, the main peak of Tanggula Mountain in Qinghai Province, it passes through the three provinces of Sichuan, Tibet and Yunnan, forming the largest hydropower base in China,The Jinsha River is the main power point for the "West-East Power Delivery. The Baihetan Hydropower Station is the most important link in the energy development of this river.
"Crane Dance Jinsha", the world's second largest hydropower station after the Three Gorges Project after its completion, has set 6 world firsts. The total installed capacity of the 16 units on the left and right banks is 16 million kilowatts, and their development, installation and commissioning are far more difficult than any units under construction or in operation in the world,Known as the world's hydropower industry "Mount Everest".Today, Baihetan Hydropower Station is telling the world the new strength of China's hydropower construction.
From Made in China to Created in China
Single-machine million kilowatts are unprecedented and no one has come.
On September 22, under the attention of the public, the number of Unit 8 on the LCD in the left bank machine room of Baihetan Hydropower Station kept beating. Unit 8 of Baihetan Hydropower Station successfully passed the 72-hour trial operation of grid-connected commissioning and officially transferred to commercial operation. This marks that all units on the left bank of Baihetan Hydropower Station have been put into operation for power generation.
Construction Scenario of Left Bank Powerhouse of Baihetan Hydropower Station
The scale of non-pressure spillway tunnel group is the first in the world.
Chen Jianlin, chief engineer of the design of the hub of the Baihetan Hydropower Project, said,The single unit million kilowatt is the most unique label for the entire hydropower station.
The power generation capacity of each generator unit is up to million kilowatts.
The spillway tunnel is discharging flood
The power generation capacity of each generator unit reaches one million kilowatts (picture provided by Zhang Mengyu)
"One million kilowatts per unit can be said to be unprecedented and unprecedented." Chen Jianlin introduced that during the preliminary demonstration of Baihetan Hydropower Station, it was found that the flow and water head of Baihetan had unique advantages and could reach the standard of one million kilowatts. But before that, the single-unit power generation capacity of the Three Gorges Dam, which has the world's largest total power generation capacity, was only 700000 kilowatts. "To build a million kilowatts of stand-alone capacity, there is no standard to refer."
How to build a single-unit million-kilowatt power generation group? "For China Power Construction Group East China Survey and Design Institute Co., Ltd. (hereinafter referred to as: East China Institute), the most important thing is to conduct feasibility studies and set standards for the unit's various indicators," Chen Jianlin said. In order not to waste the natural advantages of Baihetan Hydropower Station, the East China Institute has specially set up a relevant research group, combined with experts and scholars in the industry, carried out a lot of analysis and demonstration work, and successfully put forward feasible development parameter indicators for millions of units, including operation mode, blade type, runner processing mode, etc., thus guiding Chinese manufacturers to independently develop the international leading Baihetan hydropower unit.
Thousands of tests, thousands of demonstrations, after years of hard work, on June 28, 2021, the No. 1 and No. 14 generating units of Baihetan Hydropower Station officially generated electricity. On that day, looking at the beating numbers on the control cabinet and listening to the roar of the plant units, the construction personnel were tearful.The achievement of one million kilowatts of single-unit power generation has realized the historic leap of China's large-scale hydropower project construction from made in China to created in China, and has climbed the "Mount Everest" of the world's hydropower industry ".
Break the world-class spell
Tens of thousands of sensors build intelligent seamless dam
Between the steep cliffs, a 300-meter super-high-grade arch dam spans the river. The 709-meter arc-long arch dam is like a shield, guarding the 20.627 billion-cubic-meter huge reservoir of Jinsha River behind it, witnessing the surging river turning electricity to the east. In the 1950 s, the state began to plan the Baihetan Hydropower Station, but it took more than half a century from the site selection to the completion of the dam.
As a 300-meter-high concrete double-curvature arch dam with a maximum dam height of 289 meters,The Baihetan hydropower dam needs to overcome the huge reservoir behind it to bring about a total water thrust of about 16.5 million tons. This is equivalent to the thrust of more than 15000 Long March 5 rockets.
The spillway tunnel is discharging flood
And hydroelectric concrete dams are facing a "curse"-no dam without cracking. "In the face of such a large thrust, once the dam cracked, the consequences would be unimaginable." In order to solve this problem, the designers and engineers of Baihetan began to elaborate "design and build".
In order to ensure the safety and stability of the dam, the designers designed the dam body to bend into an arc in both horizontal and vertical directions to form an exquisite hyperbolic arch structure. At the same time, they "borrowed force to hit force" to transmit huge water thrust to both sides, and maintained the stable balance of the dam body with the help of mountain reaction force.
In addition, due to the complex and asymmetric terrain on both sides of the Baihetan Dam, the designers have made every part of the dam evenly stressed through exquisite structural design, so that it can not only carry huge water thrust, but also become the world's highest seismic fortification standard. The 300-meter high dam.
The world-class problem of mass concrete temperature control and crack prevention is also an obstacle in front of dam builders. More than 800 million square concrete, how to ensure no cracking?
Engineers continue to develop experiments, use self-developed low-heat cement concrete for the first time, and break through the theory and technology of temperature control to ensure that the dam cement concrete "does not crack".In order to be able to understand and perceive the dynamics of the dam in real time, engineers have also embedded tens of thousands of sensors in the arch dam, mastered the whole construction process through intelligent technology, and successfully built an intelligent seamless dam.
In addition, the Baihetan Hydropower Station dam has to overcome its "poor foundation" conditions, as part of the dam site is located on columnar jointed basalt, the rock mass has the characteristics of fractured and loose, can it be used as the dam foundation of the nearly 300 meters high dam? "From a practical point of view, this is not a small problem, and can even be said to affect the feasibility of the Baihetan Hydropower Station." Chen Jianlin said. Since there has been no similar case before, this "unprecedented" problem requires the entire design team to work hard to break through.
In order to clarify the complex geological conditions of Baihetan Hydropower Station, the East China Institute spent more than ten years in the early stage of continuous investigation, measurement, analysis and re-testing, and used relevant theories and technologies to propose solutions, and finally through grouting and foundation Reinforcement, energy dissipation blasting and other methods ensure the integrity of the rock formation, and ultimately enable it to carry the capacity of dam construction.
The scale of underground cavern group is the first in the world
The amount of excavation is enough to fill the two West Lakes.
Even with the experience in the design and construction of many large hydropower stations such as Jinping II Hydropower Station and Yangfanggou Hydropower Station, for Chen Jianlin, Baihetan Hydropower Station is still the most difficult one in his career so far. The more difficult place is in the excavation of underground works. "It's like a black box. I don't know what's inside." Chen Jianlin said.
To install 16 million hydropower units weighing more than 8000 tons under the steep mountain means that two huge palaces about 450 meters long, 34 meters wide and 88.7 meters high need to be taken out on the left and right banks, which is equivalent to digging two football fields underground. Chen Jianlin described the geological conditions in this "black box" as "full of uncertainty.
The pointer is set back to 2014, and the first floor excavation of the underground powerhouse will be started. "Ensure the safety of the underground powerhouse" is the key to the construction of the underground powerhouse. Due to the large scale and poor geological conditions, the stability of the surrounding rock is gradually highlighted.
In order to ensure the safety of the underground plant, the designers and engineers decided to use fine blasting and adopt the method of micro chemical loading. According to the characteristics of the rock, it is divided into 10 layers, excavated in layers from top to bottom, and blasted layer by layer. Due to the instability of the surrounding rock, each layer needs to be dynamically adjusted according to the changes of geological conditions and monitoring data. "To some extent, this is much more difficult than building a dam."
Chen Jianlin walked around the construction site of the underground powerhouse almost every day to carefully examine the data of the day to prevent the deformation of the surrounding rock from changing abruptly. But even in a layer of fine design and construction, the surrounding rock or a sudden change.
A few days before New Year's Day in 2018, at the small chainage on the right bank of Baihetan Hydropower Station, the deformation of surrounding rock increased suddenly for several consecutive days, with the maximum increase of more than 4mm in a single day, greatly exceeding the allowable deformation increment of 0.2mm per day, and continuously exceeding the two grades of "early warning" and "danger.
In the face of such a severe sudden deformation of surrounding rock, Chen Jianlin led the design team to tackle key problems immediately, came up with a response plan in time, and quickly reached a consensus with the participating parties. After grouting, strengthening the prestressed anchor cable and other ways, it was successfully reinforced and strengthened, and the danger was avoided in time.
In 2019, after more than 50 months of careful "polishing", the 438m long underground plant was finally completed.
The underground caverns on both sides of the Baihetan Hydropower Station are large in scale, and the scale is the first in the world.The water diversion and power generation system, auxiliary caverns, construction caverns and traffic caverns on the left and right banks form a huge group of underground caverns. The total length of underground caverns on both banks is 217km, and the total excavation volume of underground caverns is 25 million cubic meters, which is enough to fill two West Lakes.
6 World First
Every place in White Crane Beach is a feat
From February 2011, when the construction of Baihetan Hydropower Station was officially started, to September 2022, all units on the left bank successfully generated electricity. During the 12-year construction period, countless Chinese hydropower people worked hard in Baihetan and successively overcome more than 40 world-class problems,"The single unit capacity of hydrogenerator is 1 million kilowatts, ranking first in the world; the scale of underground cavern group is the first in the world; the scale of cylindrical tailrace surge chamber is the first in the world; the seismic parameters of 300 m high arch dam are the first in the world; the scale of pressureless flood discharge tunnel group is the first in the world; for the first time, low heat cement concrete is used in the whole dam."Six world firsts have given this "power giant" that connects Sichuan and Yunnan and spans Jinsha a more proud title.
The scale of non-pressure spillway tunnel group is the first in the world.
Chen Jianlin said that every place of the Baihetan Hydropower Station is a feat.
In his eyes, the Baihetan Hydropower Station is like a disobedient child. Under the continuous "training" of several generations of hydropower people, this disobedient child grew up step by step, turning Jinsha flowing water into rolling current and sending it to the other end of the Yangtze River, turning it into tens of millions of lights to light up thousands of lights. "Glory, gratification, pride." Chen Jianlin was filled with emotion when he saw the million kilowatt units successfully put into operation to generate electricity.
The Baihetan Hydropower Station is still working hard to realize the power generation of all units as soon as possible, and the story behind the Baihetan Hydropower Station is still going on. In the future, this great power, which carries the core competitiveness of China's electric power, will also write its own brilliant story on the Jinsha River.
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Chen Jianlin, Chief Design Engineer of Dialogue Project Hub:
This project has taken the painstaking efforts of several generations of hydropower people and is a project that benefits the country and the people.
Cover news: Baihetan Hydropower Station in addition to providing huge power generation, what other major functions and functions?
Chen Jianlin: In addition to providing a large amount of power generation, we also have flood control functions. Baihetan has a storage capacity of 20.6 billion cubic meters, of which the flood control capacity is 7.5 billion cubic meters. The joint use of Baihetan and the Wudongde, Xiluodu and Xiangjiaba cascade reservoirs in the lower reaches of the Jinsha River can further improve the flood control standards of Yibin, Luzhou and Chongqing along the Sichuan River. At the same time, it can reduce the flood into the Three Gorges Reservoir and undertake the flood control task in the middle and lower reaches of the Yangtze River. In addition, there are comprehensive benefits such as improving downstream shipping conditions and promoting local economic and social development, energy saving and emission reduction. The average annual power generation reaches 62.4 billion kWh, which can save 19.68 million tons of coal and reduce carbon dioxide emissions by 51.6 million tons, which is for the early realization of "double carbon". The strategy contributes to Baihetan's strength.
Cover news: Baihetan Hydropower Station has won six world firsts. What high-tech content does it have?
Chen Jianlin: We use some intelligent construction technologies and BIM technology to design hydraulic structures and electromechanical arrangements.But more we are striving for excellence in the construction technology of hydropower stations. For example, our single-unit power generation reaches one million kilowatts, the surrounding rock stabilization technology of underground engineering, the smooth and seamless concrete, and the flood discharge and energy dissipation are all achieved. The world's top level.
Cover news: As the chief designer who has completely experienced the construction of Baihetan Hydropower Station, how many key words would you use to describe Baihetan Hydropower Station?
Chen Jianlin: The first is the giant hydropower project. The single-unit power generation reaches one million kilowatts. This is what we are most proud. Secondly, it is majestic, like our dam, especially when the flood is discharged, the scene is extremely spectacular, and the scale of our underground caverns is also very grand. The third is the big country project, which has taken the painstaking efforts of several generations of hydropower people and is a project that benefits the country and the people.
Baihetan Hydropower Station Flood Discharge
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