China News Service, Zhaotong, June 28th, title: The birth of the Baihetan hydropower unit with the largest single-unit capacity in the world
Author Miao Chao Dao Zhi Nan Li Jiaxian
The Baihetan Hydropower Station, the world's largest under construction, realized the first batch of generating units formally put into operation on the 28th.
After the Baihetan Hydropower Station is fully completed, it is estimated that the annual average power generation will be 62.443 billion kWh, which will save about 19.68 million tons of standard coal and reduce the emission of carbon dioxide by 51.6 million tons.
On the same day, the reporter walked into the Baihetan Hydropower Station and explored the "heart" of the hydropower station in the underground powerhouses located deep in the mountains on both sides of the Jinsha River-the birth history of the world's largest single-unit capacity of 1 million kilowatts of hydro-turbine generators.
The picture shows the underground powerhouse on the right bank of Baihetan Hydropower Station.
Miao Chao photo
The past and present of the 1 million kilowatt unit
The use of 1 million kilowatt units in Baihetan Power Station is not an overnight effort, but a long-term process of demonstration, exploration and practice.
Harbin Electric Group Co., Ltd. is responsible for the development of eight 1 million kilowatt units on the right bank of Baihetan Hydropower Station.
Tao Xingming, deputy general manager of the group’s electrical machinery company, told reporters that at the first national scientific planning meeting held in 1958, experts submitted the "Preliminary Opinions on the Demonstration of the Capacity of the Three Gorges Project Hydropower Units" and proposed to develop 300,000 kilowatts, 450,000 kilowatts, and 600,000 kilowatts , 800,000 kilowatts, 1 million kilowatts hydroelectric generating units and other five project ideas, as well as the corresponding design parameters, structure, dimensions and assembly drawings.
This is the starting point of the dream-seeking process of the "Millions of Hydropower Units".
The period from 2006 to 2007 is the gestation period for the million-kilowatt unit.
In February of that year, the experts submitted the "Million Kilowatt Unit Feasibility Analysis Report" to the China Hydropower Planning and Design Institute.
On March 8th of the same year, Three Gorges Group and East China Survey, Design and Research Institute jointly issued the "1 million kilowatt hydro-turbine generator set technical consultation letter". Representative enterprises in the industry have made the use of 700,000 kilowatts, 75 million kilowatts and 75 million kilowatts in the Baihetan Hydropower Station. The technical demonstration of 10,000-kilowatt, 800,000-kilowatt, and 850,000-kilowatt units has also boldly put forward the idea of setting up a million-kilowatt unit.
Tao Xingming said that in August 2007, the Ministry of Science and Technology established the key technology research project of million-kilowatt hydro-turbine generators in the Science and Technology Support Program. Three Gorges Corporation also cooperated with Harbin Electric Group Co., Ltd. to jointly develop a million-kilowatt scientific research project.
With the continuous development and progress of China's hydropower technology, especially in 2007, the first 700,000-kilowatt unit of the Three Gorges Right Bank Power Station was put into operation, and the research and development of the 770,000-kilowatt unit in Xiluodu and the 800,000-kilowatt unit in Xiangjiaba ended. China has large-capacity hydropower. The complete independent intellectual property rights of the unit indicate that China has the technical foundation for independently developing a 1 million kilowatt hydropower unit.
"In October 2011, at the Baihetan feasibility stage installed capacity selection review meeting, the state approved the feasibility of 1 million kilowatt units. It was determined that all Baihetan hydropower stations should be equipped with 1 million kilowatt hydropower units." Tao Xingming told reporters. In the process, they began to realize their dreams.
He recalled that when discussing the single-unit capacity of the Baihetan power station, some experts had proposed the use of 2 units of 1 million kilowatts and the remaining units of 800,000 kilowatts for the sake of safety.
Later, it was determined that all 1 million kilowatts, which is also a pioneering work in the world.
"Therefore, this problem, on the one hand, is the transcendence of technology, which has fulfilled the needs of the market; on the other hand, it is also due to the needs of the market that have catalyzed the progress of technology.
The picture shows the largest Baihetan Hydropower Station under construction in the world.
Photo by Li Jiaxian
96.7% efficiency is the world's leading level
As the "heart" of a hydropower unit, the runner is the most difficult component in the development and manufacturing of the unit, and also the most critical component that affects the operating efficiency and stability of the unit. It can be called the "Crown on Mount Everest".
Tao Xingming introduced that since the launch of the National Science and Technology Support Program million kilowatt hydraulic performance study in 2007, everyone has been standing at the strategic level of "high-quality development", from the long-term perspective of "bringing maximum economic and social benefits to the country and owners". Starting from the goal, we will carry out research on national scientific research topics, and conduct in-depth research on 7 topics including hydraulic design and stable performance of hydraulic turbines.
In order to decipher the limit code of "the best overall efficiency of the runner", according to the characteristics of high water head, high voltage level and large capacity of the unit, the generator and water turbine runner are optimized for multiple rounds according to local conditions. The model runner of the water turbine Thirteen runner models have been developed successively.
After many comparisons, they finally innovatively chose a runner with 15 long and 15 short blades.
Through unremitting efforts, the optimal efficiency of the Baihetan runner has been increased to 96.7%, and the stability of the runner's operation has reached a new height.
Tao Xingming said, "The comparison results on the same platform show that the comprehensive indicators of the optimal efficiency, weighted average efficiency and hydraulic stability of the hydraulic turbine model we developed have reached the international leading level."
Tao Xingming explained that he chose the long and short blade runner because he was optimistic about its excellent overall performance.
Compared with conventional runners, long and short blade runners are more "omnipotent". It perfectly combines the advantages of long blades and short blades. The energy conversion of the unit operation is more sufficient, the stability is better, the cavitation performance is better, and it is further improved. In order to achieve the highest efficiency and weighted average efficiency of the unit's operating efficiency, the stability and safety of the unit within the full-load operation range can be achieved qualitatively, and full-load regulation operation can be realized.
From April 2018 to June 2021, in more than three years, the runners with a diameter of 8.87 meters, a height of 3.8 meters and a total weight of 338 tons have all reached or exceeded the quality standards. The third one is even better. It is the world's first giant long and short blade runner with "zero counterweight" breakthrough performance, which can be called the "natural and excellent heart" of Baihetan hydropower unit.
Tao Xingming said that, like a densely intertwined network, every link in the development of the runner is crucial.
"During the manufacturing process, we implemented refined solutions to improve manufacturing accuracy throughout the entire process. By improving the welding procedure, the pass rate of the welding seam of the runner was greatly increased; the proprietary long and short shaft turning technology was adopted to avoid the reverse turning when turning over. The wheel size has an adverse effect; the unique heat treatment support tool ensures that the runner does not deform at a high temperature of 580 degrees Celsius; the advanced optical digital measurement technology controls the angle deviation of the runner blades within ±0.5°, and the accuracy is increased by more than 2 times. "
It is reported that Baihetan 1 million kilowatt generating unit, as another "national card" of China's hydropower leading the world, has an epoch-making milestone in the history of hydropower construction and has created a new world record for hydropower equipment.
After the Baihetan Hydropower Station is fully completed, it will form the world’s largest clean energy corridor with the Wudongde, Xiluodu, and Xiangjiaba hydropower stations on the Jinsha River, as well as the Three Gorges and Gezhouba hydropower stations. The main role of the national team.
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