The wind turbine willWind energyConvert toMechanical workThe mechanical power drives the rotor to rotate and finally outputs the AC power.Wind turbine generally consists of wind turbine, generator (including device), direction adjuster (tail wing), tower, speed limiting safety mechanism, energy storage device and other components.
The working principle of the wind turbine is relatively simple. The wind wheel rotates under the action of the wind, which converts the kinetic energy of the wind into the mechanical energy of the wind wheel shaft. The generator rotates to generate electricity under the drive of the wind wheel shaft.Broadly speaking, wind energy is also solar energy, so we can also say that wind turbine is a kind of wind turbine that uses the sun as the heat source and the atmosphere as theWorking mediumThe thermal energy of the generator is utilized.
For many centuries, wind turbine, like hydraulic machinery, has played an important role in the development of productivity as a source of power instead of human and animal power.The wide application of modern electromechanical power and the discovery of oil fields in the Middle East in the 1950s madeWind turbineThe development of has slowed down.
In the early 1970s, due to“oil crisis ”The problem of energy shortage arises, and people realize thatMineral energyThe supply is unstable and limited, so the search for clean renewable energy has become an important topic in the modern world.Wind energyAs renewable and pollution-freeNatural energyIt has aroused people's attention again.
Is to convert wind energy intomechanical energy, electrical equipment that converts mechanical energy into electrical energy.Broadly speaking, it uses the sun as the heat source and the atmosphere as theWorking mediumThe heat energy of the engine is utilized.Wind power uses natural energy.relativediesel oilPower generation is much better.But if it is used for emergency, it is not as good as diesel generator.Wind power generation can not be regarded as standby power supply, but it can be used for a long time.
The principle of wind power generation is to use the wind to drive the windmill blades to rotate, and then increase the speed of rotation through the booster engine to promote the generator to generate electricity.According to the current wind turbine technology, the wind speed is about three meters per second (the degree of light wind), and power generation can start.
Wind power generation is forming an upsurge in the world, because wind power generation has no fuel problem, and will not produce radiation or air pollution.
Wind power is very popular in Finland, Denmark and other countries;Our country also vigorously advocates in the western region.Small wind power generation system is highly efficient, but it is not composed of only one generator head, but a small system with certain scientific and technological content: wind turbine+charger+digitalinverter。The wind turbine is composed of head, swivel, tail and blade.Each part is very important. The functions of each part are: the blades are used to receive wind power and convert it into electric energy through the nose;The tail wing makes the blades always face the direction of the incoming wind to obtain the maximum wind energy;Swivel can make the nose rotate flexibly to realize the function of tail wing direction adjustment;HandpiecerotorIs a permanent magnet,stator winding Cutting magnetic lines of force generates electricity.
The output of wind turbine varies from 13 to 25V due to unstable air volumealternating current, must be rectified by the charger, and then storedBatteryThe electric energy generated by the wind turbine can be changed into chemical energy by charging.Then use the inverter power supply with protective circuit to convert the chemical energy in the battery into AC 220V mains power to ensure stable use.
Mechanical connection and power transmission: horizontal axisFanPaddle passingGearboxIts high-speed shaft is connected with the universal elastic coupling to transmit the torque to the transmission shaft of the generator. This coupling should have good characteristics of absorbing damping and vibration, which can absorb an appropriate amount of radial, axial and certain angle offset, and the coupling can prevent the overload of the mechanical device.The other is the direct drive fan whose blades are directly connected to the motor without gearbox
Generator structure
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engine room: The cabin contains the wind turbineKey equipment, including gearbox and generator.Maintenance personnel can enter the engine room through the wind turbine tower.The left end of the engine room is the rotor of the wind turbine, namelyRotor bladeAnd shaft.
Rotor blade: Capture the wind and transmit it to the rotor axis.On a modern 600kW wind turbine, the measured length of each rotor blade is about 20 meters, and it is designed very much like the wing of an aircraft.
axis: The rotor axis is attached to the low-speed shaft of the wind turbine.
Low speed shaft: The low-speed shaft of the wind turbine connects the rotor axis with the gearbox.On modern 600kW wind turbines, the rotor speed is quite slow, about 19 to 30 revolutions per minute.The shaft has a conduit for the hydraulic system to stimulate the operation of the pneumatic brake.
Gearbox: The left side of the gearbox is the low-speed shaft, which can increase the speed of the high-speed shaft to 50 times that of the low-speed shaft.
High speed shaft and its mechanical brake: The high-speed shaft runs at 1500 rpm and drives the generator.It is equipped with an emergency mechanical brake, which is used when the aerodynamic brake fails or the wind turbine is repaired.
alternator: commonly referred to as induction motors orAsynchronous generator。On modern wind turbines, the maximum power output is usually 500 to 1500 kilowatts.
Yaw device: Turn the engine room with the help of the motor to make the rotor face the wind.The yaw device is composed ofElectronic controllerDuring operation, the electronic controller can sense the wind direction through the wind vane.Usually, when the wind changes its direction, the wind turbine will deflect only a few degrees at a time.
Electronic controller: It includes a computer that continuously monitors the status of the wind turbine generator and controls the yaw device.To prevent any fault (i.e. overheating of the gearbox or generator), the controller can automatically stop the rotation of the wind turbine andModemTo call the WTG operator.
Hydraulic system: Used to reset the aerodynamic brake of the wind turbine.
Cooling element: Contains a fan to cool the generator.In addition, it contains an oil cooling element for cooling the oil in the gearbox.Some wind turbines have water-cooled generators.
Pagoda: The wind turbine tower contains the engine room and rotor.Usually, tall towers have advantages, because the higher the tower is above the ground, the greater the wind speed.Modern 600kW windSteam turbineThe height of the tower is 40 to 60 meters.It can be a tubular tower or a lattice tower.Tubular towers are safer for maintenance personnel because they can reach the top of the tower through an internal ladder.The advantage of the lattice tower is that it is cheaper.
Anemometer and wind vane: Used to measure wind speed and direction
Tail rudder:Common in upwind direction of horizontal axisSmall wind turbine(generally 10KW and below).It is located behind the swivel and connected with the swivel.The first main function is to adjust the rotation direction of the fan so that the fan is facing the wind direction.The second function is to make the head of the wind turbine deviate from the wind direction under strong wind conditions, so as to reduce the speed and protect the wind turbine.
Generator type
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According to constant pitch stall type fan and variable speed constant frequencyPitchThe characteristics of torque fans are generally divided into two types of motors currently installed in China:
1. Asynchronous type
(1) Cage type asynchronous generator;Power: 600/125kW, 750kW, 800kW, 12500kW
statorDeliver 50Hz alternating current of different power to the power grid;
(2) Wound doubly fed induction generator;Power is 1500kW
The stator transmits 50Hz AC power to the power grid, and the rotor is controlled by the frequency converter to indirectly transmit active power orReactive power。
2. Synchronous type
(1) Permanent magnetSynchronous generator；Power: 750kW, 1200kW, 1500kW, generated by permanent magnetmagnetic fieldThe stator output transmits 50Hz AC power to the power grid after full power rectification and inversion
(2) Electro excited synchronous generator;The magnetic field is generated by the DC current externally connected to the rotor, and the stator output transmits 50Hz AC power to the power grid after full power rectification and inversion
According to different blade types, existing wind turbines are divided into the following two categories:
3. Horizontal axis
At present, it is the most widely used form in the world, with a maximum power of about 5MW.
4. Vertical axis
A new type of wind turbine invented by China, Japan and Europe at the beginning of the 21st century is different from the earliestVertical axis wind turbine(Darieu type), the efficiency is higher thanHorizontal axis wind turbineNo noise and steering mechanism, simple maintenance.It has become the first choice of small and medium-sized wind turbines in European and American markets.At present, the maximum power in the world is the 50kW vertical axis wind turbine produced by Shanghai Moose Electronic Equipment Co., Ltd. (MUCE), the maximum power in Japan is 30kW, and the power produced in Britain and America is between 1kW and 10kW.
Recently, many companies at home and abroad have put forward the plan of building super large vertical axis wind turbines (10MW). After the implementation of this plan, because the cost is far lower than the current wind turbines, it will gradually replace the horizontal axis wind turbines and become the main force of new energy in the world!
1kw vertical axis wind turbine
Approach to reliability
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The research shows that the ways to improve the reliability of wind turbines mainly include the following contents.[1]
Technical personnel training
First, we need to build aengineerTeam, train engineers to gradually master reliability theory in the process of work, and let them understand the impact of reliability onWind turbineThe importance and significance of operation and development.[1]
reliability design
reliabilityengineerIt is necessary to pay attention to reliability in the early stage of product design, and evaluate the impact of design concepts on reliability.At the same time, the computer aided engineering analysis software is used to repeatedly design and test the products to solve the design problems, so as to design a model of high reliability wind turbine.[1]
Reliability test
The component supplier of the wind turbine must make the formal test routine to ensure the reliability of the accessories. At the same time, it is absolutely necessary for the prototype assembly test of the wind turbine.Reliability testThe purpose of the system is to find potential problems as early as possible and finally make the system meet its reliability.Reliability testing shall be carried out at multiple levels, especially for complex systems at all levels of components, assembly processes, subsystems and systems.For example, each component should be tested first, and then the overall test should be carried out after the test is passed, so as to reduce the project risk.In system reliability test, reliability failure report shall be generated after each level of test, and then analyzed and corrected, so as to improve the level of reliability test.Although this kind of test will cost a lot of time and expense, it is worth comparing with the losses caused by long-term downtime due to failure and instability of products in actual operation.For offshore wind turbines, such tests need to be strictly carried out.[1]
Install monitoring system
Wind turbine equipment can use such as vibration monitoring and analysis equipment or install precision instruments that can detect early signs of emergency failure.These Condition Monitoring System (CMS) can trigger the maintenance process when problems are found beyond the warning.Therefore, predictive maintenance and condition based maintenance are also important ways to improve system reliability.[1]
Development in China
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In 2006, China had a total of 6469 wind turbines, of which megawatt units accounted for 21.2%. In 2007, the proportion jumped to 38.1%, an increase of 16.9 percentage points.In 2007, the cumulative installed capacity of global wind power generation reached 94100 MW, an increase of 27% over the previous year's 74200 MW.In 2007, the installed capacity of wind power in China was 6.05 million kilowatts, realizing the planned goal of 2010 three years ahead of schedule;In the six years from 2001 to 2007, China's installed wind power capacity increased 14 times;In 2007 alone, China's wind power installed capacity increased by 3.449 million kilowatts, more than the cumulative total of wind power in China's history.With the rapid development of wind power industry,Wind power equipmentdemand exceeds supply.[2]
In recent years, wind power in emerging markets has developed rapidly.Under the background of national policy support and tight energy supply, China's wind power, especially wind power equipment manufacturing industry, has also risen rapidly, and has become the most active place for wind power in the world.In 2006, 9% of the global wind power funds were invested in China, with a total amount of 1.62 billion euros (about 16.27 billion yuan).In 2007, China's installed capacity of wind power ranked fifth in the world.[2]
China's huge wind power market and cheapLabor cost, attracted a large number of foreign wind power giants to set up factories in China, or take the form of joint ventures with domestic enterprises, and the products produced are labeled "Made in China".Wind power equipment products made in China occupy an increasing market share, and wind turbine products are undergoing a transformation from global manufacturing to Chinese manufacturing.[2]
As wind power belongs to the category of new energy, there is still a big gap between the cost and technology of wind power and traditional thermal power and hydropower, so the rapid development of wind power needs strong support from national policies.Throughout the rapid development of wind power in countries such as Germany, Spain and India, there is no exception to give huge policy preferences to the wind power industry.China's policy support for wind power has a long history and is increasingly strong. The object of policy support has shifted from focusing on power generation in the past to focusing on supporting domestic wind power equipment manufacturing.The national policy support will be the fundamental guarantee for the rapid development of the wind power equipment manufacturing industry. With the continuous strengthening of the independent manufacturing capacity of China's domestic wind turbine equipment, the national policy support will also be more and more strong, and the wind power equipment manufacturing industry will face a rare historical development opportunity.[2]
China is at a good time for the development of wind power (wind power market research), and the demand for wind power equipment market is increasing.In addition, in addition to the increasing demand for wind power equipment, the supply capacity of blades, gearboxes, large bearings, electric controls and other wind power equipment parts still cannot fully meet the demand, and the market growth potential is huge.Therefore, China's wind power equipment manufacturing industry continues to boom.[2]
In November 2015, China's largest offshore wind turbine was successfully installed in Pinghai Bay, Putian, Fujian Province.The fan is XE128-5000, with a unit capacity of 5MW, a runner diameter of 128 meters, and a hub center height of 81 meters. It is a 50MW offshore wind power project in Pinghai Bay, Putian, Fujian Province.[3]
On October 27, 2020, on the wind turbine tower 0.7 nautical miles away from the southern branch channel of the Yangtze River Estuary, the Shanghai Aids to Navigation Office of the East China Sea Navigation Support Center successfully completed the construction of the AIS (Automatic Identification System of Ships) base station of the offshore wind farm near the port on October 27, 2020, and China's first offshore wind turbine tower AIS base station was announced to be completed.[4]
On February 23, 2021, the world's first 12MW offshore semi direct drive permanent magnet synchronous wind turbine independently developed by China will be launched in CRRC Zhuzhou Electric Machinery Co., Ltd. As the world's largest semi direct drive wind turbine at present, the annual power generation of this product after installation will reach 58GWH, which can meet the annual power demand of 145000 ordinary families,The annual emission reduction exceeds 27550 tons of carbon dioxide (equivalent to 18000 cars).12MW offshore semi direct drive permanent magnet synchronous wind turbine is the largest wind turbine exported by China. Later, this product will be exported to the European market in batches within the year, which is of great significance for promoting the development of China's offshore wind power generation equipment.[5]
On March 29, 2021, the first domestic 5.5 MW onshore permanent magnet direct drive wind turbine with fully independent intellectual property rights was launched in the Shandong Wind Turbine Manufacturing Base of Dongfang Electric Machinery Co., Ltd., marking the success of the largest onshore permanent magnet direct drive wind turbine in China at present.[6]
Wind Power Outlook
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It is generally believed that the power of wind power generation is completely determined by the power of wind turbines, and people always want to buy larger wind turbines, which is incorrect.At present, wind turbines only charge the battery, and the battery stores the electric energy. The size of the battery is more closely related to the size of the electric power that people eventually use.The power mainly depends on the air volume, not only the head power.In the mainland, small wind power generation opportunities are more suitable than large ones.Because it is more likely to be driven by small wind volume to generate electricity, the continuous small wind can supply more energy than the temporary strong wind.When there is no wind, people can also use the power brought by the wind normally, that is to say, a 200W wind turbine can also obtain 500W or even 1000W or more power output through the cooperation of large batteries and inverters.
The use of wind turbines is to continuously turn wind energy into the standard municipal electricity used by our families. The degree of saving is obvious. A family's annual electricity consumption costs only 20 yuan of battery liquid.However, the performance of the current wind turbine is much better than that of a few years ago. It was only used in a few remote areas before. The wind turbine is connected to a 15W bulb to directly use electricity, and the bulb is often damaged when it is on and off.Now, due to technological progress, with advanced chargers and inverters, wind power generation has become a small system with certain scientific and technological content, and can replace normal municipal power under certain conditions.The mountain area can use this system to make a street lamp without spending money all the year round;It can be used as a road sign light at night on expressways;Children in mountainous areas can study by themselves at night under fluorescent lamps;Wind turbines can also be used on the roofs of small high-rise buildings in cities, which is not only economical but also a real green power supply.Household wind turbines can not only prevent power failure, but also increase the interest of life.In tourist attractions, border defense, schools, troops and even backward mountainous areas, wind turbines are becoming a hot spot for people to purchase.Radio enthusiastWe can use our own technology to serve people in mountainous areas in wind power generation, so that people can watch TV and use electricity for lighting in step with the city, and also make themselves rich through labor.
In May 2009, the state invested 3 trillion yuan to support new energy, especially the wind power industry.The state strongly supports the development of wind power!
