On July 19th, facing the wind of the Bohai Sea, the world’s largest single unit wind turbine started generating electricity at the Huaneng Xianren Island Thermal Power Plant in Yingkou, Liaoning.
This white “windmill” has set two global records with a wind turbine diameter of 260 meters and a single unit power of 18 megawatts. With its continuous rotation, it can generate 18000 kWh of clean electricity per hour at full wind speed, which can increase the power generation by 125% compared to the largest operating 8-MW wind turbine model in Liaoning region.
It is understood that the domestication rate of this “windmill” exceeds 99%. The generator assembled on the wind turbine is an offshore semi direct drive permanent magnet wind turbine independently developed by Xi’an CRRC Yongdian Jieli Wind Energy Co., Ltd. (hereinafter referred to as Jieli Company).
The layout of the ‘windmill’ on the sea rises in the wind
Currently, offshore wind power is becoming an important lever for China to promote energy transformation. Data shows that within a water depth range of 5 to 50 meters in the near sea, the technological development of wind energy resources is about 500 million kilowatts, and the exploitable amount of deep-sea wind energy resources is 3 to 4 times that of the near sea.
In recent years, Jieli Company’s offshore wind power projects have received frequent good news, continuously creating records such as “largest in China” and “largest in the world”, gradually realizing the market potential of offshore “windmills”.
The development of a 10. XMW offshore compact permanent magnet synchronous wind turbine and its domestic maximum power semi direct drive experimental platform has filled the domestic gap; The XMW offshore compact permanent magnet semi direct drive wind turbine was launched in July 2021, becoming the world’s largest compact offshore permanent magnet semi direct drive wind turbine at that time; Assisting the first grid connected power generation project of the “14th Five Year Plan” offshore wind power base – Shandong Energy Bohai Sea Wind Farm successfully connected to the Bohai Sea for power generation
Looking back at the development history of offshore wind turbines in China, the autonomy has been continuously enhanced, the installed capacity has significantly increased, and the unit capacity has achieved continuous breakthroughs from 8 MW, 10 MW, 12 MW to 16 MW. Nowadays, offshore wind turbines with a single capacity of 18 megawatts have started generating electricity in Yingkou, Liaoning, marking the trend of the trend of offshore wind turbines.
During the 14th Five Year Plan period, some institutions made predictions on the total installed capacity and single unit power of offshore wind power. We originally thought that by today, the single unit capacity would reach 12 to 15 megawatts, but we did not expect to have reached 18 megawatts now. In the next one or two years, we may be able to reach 25 megawatts, “said Mi Xingshe, General Manager of Xi’an CRRC Yongdian Jieli Wind Energy Co., Ltd.
A wind power industry researcher told reporters that the considerable economic efficiency is closely related to the large-scale wind turbines used. The increasing size of offshore windmills means a decrease in sea area, steel structure construction, and maintenance costs. At the same time, under the same wind speed conditions, large-scale offshore wind turbines will also increase the utilization hours of wind turbines and increase the effective power generation.
According to Mixing Society, as of 2024, the total installed capacity of Jieli Company’s offshore generators has reached 3000 megawatts. At present, Jieli Company is developing a 25 megawatt class ultra-high power density semi direct drive generator for the deep sea, continuing to catch up with the goal of being the “world’s largest”.
Breakthrough to install a ‘strong heart’ for the ‘giant’
What is the capacity of an 18 MW wind turbine? The answer given by Mixing Society is that the unit can output 74 million kilowatt hours of clean electricity per year, which is equivalent to saving about 25000 tons of standard coal and reducing carbon dioxide emissions by about 61000 tons per year.
So, how can a ‘windmill’ meet the annual electricity demand of 40000 households? The core component of the generator set that converts wind energy into electrical energy, the generator, is crucial.
The generator assembled on the world’s largest single unit capacity wind turbine is an offshore semi direct drive permanent magnet wind turbine independently developed by Jieli Company. Its single unit power is “the world’s first” and it has been selected as a leading technology in the “Science and Technology Innovation China” (green and low-carbon field), overcoming multiple technical challenges such as structural integration and heat dissipation balance of high-power wind turbines.
As the capacity of wind turbines continues to increase, various problems have become increasingly prominent, and generators have always been an unavoidable part of the development of large-scale wind turbines.
How to ensure that the motor will not be unable to transmit safely due to excessive current after increasing the motor power to a super large level—— The multiple winding designs of Jieli Company came in handy. By adopting this design, the loss of power generation caused by motor failures can be minimized to the greatest extent possible.
What should we do about the temperature rise of the generator that comes with the increase in motor power? It is reported that Jieli Company adopts the company’s unique patented dual cycle high-efficiency cooling technology of stator water cooling and rotor air water cooling, achieving the effect of “low temperature rise” through the combination of “water cooling+air cooling”.
In the process of power transmission, harmonics, as an “uninvited” factor, seriously affect the quality of power generation. What should be done? In order to reduce the harmonic content of wind turbines, Jieli Company adopts a special slot design and optimizes the size of the rotor magnetic pole structure to reduce oscillations caused by high-power capacitors and inductors.
The instability of offshore wind power generation poses a reliability challenge to large-scale offshore wind turbines. Due to the high cost of lifting at sea, our design principle is to have high reliability, ensuring a service life of at least 25 years and avoiding major quality issues, “said Mixing Society.
Chain casting uses “wind” as a medium to connect more enterprises
How many core components does a wind turbine consist of? From the main bearings of the wind turbine to the blades and then to the generator, tens of thousands of components shine brightly in a ‘big windmill’, “Mixing Society told reporters with a smile.
Speaking of just one of the generators, behind it are the names of multiple enterprises and research institutions such as Xi’an Thermal Power Research Institute Co., Ltd., Weidi Technology (Xi’an) Co., Ltd., and Xi’an Kangben Materials Co., Ltd. In the view of Mixing Society, “the ‘smart’ manufacturing of ‘big windmills’ relies on clustered technological innovation as the key
Carbon fiber is an excellent material for manufacturing high-tech equipment such as aerospace. So, can this material be used on generators? With the continuous increase in single unit power of wind turbines and the urgent requirement for high power density of generators, the high strength and low density characteristics of carbon fiber composite materials make them an ideal choice for manufacturing internal components of motors.
In the future, Kangben will fully leverage its advantages in aerospace composite materials to assist in the installation and operation of large-scale offshore wind turbine products, “said Wang Fuqiang, Deputy General Manager of Xi’an Kangben Materials Co., Ltd.
In addition, Jieli Company has also partnered with Xi’an Thermal Power Research Institute Co., Ltd., Weidi Technology (Xi’an) Co., Ltd. and other enterprises to develop wind turbine bearing application technology with less shaft current damage. The core components of the ‘Big Windmill’ have always relied on imports in the past, and the road to domestic substitution is extremely difficult. In the future, under the guidance of technological innovation, China will completely break free from the situation of being controlled by others, and promote offshore wind power projects to the deep sea with better wind speed conditions and more stringent construction conditions, “said Mixing Society.
Looking ahead to the future, Mixing Society stated that it will continue to collaborate with the upstream and downstream industrial chains of wind power, adhere to technological innovation breakthroughs, promote innovative allocation of production factors, promote deep industrial transformation and upgrading, continuously accelerate the formation of new quality productive forces, and contribute more green momentum to the comprehensive development of the economy and society.
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