Wind turbines with a power generation of 10 kW or less
Generally, wind turbines with power generation of 10 kW or less are called small wind turbines.small-scalewind poweralternatorIt mainly consists of the following parts: wind turbinealternatorRotary body, speed regulating mechanism, direction adjusting mechanism, brake mechanism and tower.
Generally, wind turbines with power generation of 10 kW or less are called small wind turbines.
History
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Human beings have used wind energy for thousands of years. At first, they mainly used wind power to lift water for irrigation, sea water for salt drying and wind driven mills.At that time, human beings used the power of nature to drive working machinery by using wind and water power instead of human and animal power, which improved productivity.As for human beings' use of wind energy to drive ships, it can be traced back to more ancient times.
The large-scale development and application of wind turbines in China, especially small wind turbines, began in the 1970s, when wind powered water extractors were developed for irrigation and salt fields in coastal areas, and high-power wind turbines were developed for coastal areas in Zhejiang and Fujian,Especially in Inner Mongolia, due to the support of the government and the adaptation to the needs of local natural resources and local people, the research and promotion of small wind turbines have been greatly developed.It has played a great role in solving the problem of living electricity and part of production electricity for the scattered farmers and herdsmen living in remote areas.
With the worldwide environmental protectionGlobal greenhouse effectAll countries are competing to develop the utilization technology of renewable energy, including wind energy, and regard wind energy as a choice of energy policies for sustainable development. Both large grid connected wind turbines and small off grid wind turbines suitable for farmers and herdsmen in remote areas have been given great policy support.China has 24 wind farms with grid connected wind turbines, with a total installed capacity of 268000 kilowatts.The number of small wind turbines exceeds 140000, making China the country with the largest number of small wind turbines in the world.
Composition of small wind turbine: small wind turbine generally consists of the following parts: wind wheel, generator, speed regulation and direction adjustment mechanism, parking mechanism, tower and cable, controller, battery, inverter, etc.
①Wind wheel: The wind wheel of small wind turbine is mostly composed of 2~3 blades. It is a component that converts wind energy into mechanical energy.There are two main materials of wind turbine blades.One is glass fiber reinforced plastic, which is generally usedGlass fiber clothIt is manually pasted with the prepared epoxy resin in the model, and some filling materials are added to the inner cavity. The manual pasting is suitable for blades with different shapes and variable cross sections, but manual manufacturing is time-consuming, and the product quality is not easy to control.Foreign small fans also adopt mechanized production of blades with equal cross section, which greatly improves the efficiency of blade production and product quality.
②alternator: Small wind turbines generally adopt permanent magnet typealternatorThe AC generated by the wind turbine driven generator is converted into DC that can be stored in the battery after rectification.
③Direction adjusting mechanism, speed regulating mechanism and parking mechanism: In order to obtain energy from the wind, the rotating surface of the wind wheel should be perpendicular to the wind direction. In small wind turbines, this function is realized by using the tail fin of the wind turbine as the direction adjustment mechanism.At the same time, with the increase of wind speed, the speed of the wind turbine should be limited, because on the one hand, too fast speed will damage the wind turbine and other parts of the wind turbine, on the other hand, the power output of the generator needs to be limited to a certain range.Due to the simple structure of small wind turbine, the impeller side deflection speed regulation mode is generally adopted. This speed regulation mechanism is prone to cause the swing of the wind wheel and tail wing when the wind speed and direction change, thus causing the vibration of the wind turbine.Therefore, when the wind speed is high, especially when the battery has been fully charged, the wind turbine should be stopped manually.In some small wind turbines, a manual brake mechanism is designed. In addition, in practice, a sidetracking shutdown mode can be used, that is, a soft rope is fixed on the tail wing. When it is necessary to stop, pull the tail wing to make the wind wheel side to the wind direction, so as to achieve the purpose of stopping.
classification
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Classification by axis position
According to the position of wind turbine shaft, it can be divided into horizontal axis wind turbine andVertical axis wind turbine。
（1）Horizontal axis wind turbine: The wind wheel of the horizontal axis wind turbine rotates around a horizontal axis, and the wind wheel axis is parallel to the wind direction,The blades on the wind turbine are installed radially, perpendicular to the rotation axis and at an angle with the rotation plane of the wind turbine (called the installation angle).The number of wind turbine blades is 1~10 (mostly 3, 5, 6). It has a high utilization rate of wind energy when running at high speed, but needs a high wind speed when starting.
（2）Vertical axis wind turbine: The wind wheel of the vertical axis wind turbine rotates around a vertical axis, and the wind wheel axis is perpendicular to the wind direction.Its advantage is that it can accept the wind from any direction, so when the wind direction changes, there is no need to face the wind.
Classification by power
According to the power of wind turbines, they can be divided into large, medium, small and micro wind turbines.If the power is less than 1KW, it is a mini 1~10KW wind turbine. If the power is between 10kW and 100KW, it is called a medium-sized wind turbine. If the power is more than 100KW, it is called a large wind turbine. If the power is more than 100KW, it is called a megawatt level wind turbine.
However, with the breakthrough of single unit capacity, 1MW and above wind turbines are gradually called medium and large wind turbines.Small wind turbines have a single capacity of several hundred kilowatts.
Momentum blade element theory is widely used in blade design of horizontal axis wind turbine, and the main methods are Glauert method, Wilson method, etc.However, because the blade element theory ignores the flow interference between each blade element, and at the same time ignores the resistance of the airfoil when using the blade element theory to design blades, this simplification inevitably leads to inaccuracy of the results. This simplification has less impact on the blade shape design, but has greater impact on the wind energy utilization of the wind turbine.At the same time, the interference between the blades of the wind turbine is also very strong, and the whole flow is very complex. If only relying on the blade element theory, there is no way to get accurate results.
Vertical axis wind turbineIn the past, the design of the blade was also based on the horizontal axis design method and leaf element theory.Since the flow of the vertical axis wind turbine is more complex than that of the horizontal axis, which is a typical large separation unsteady flow, it is not suitable for analysis and design with the blade element theory, which is also an important reason why the vertical axis wind turbine cannot be developed for a long time.
Wind energy utilization rate
Most of the wind energy utilization rate of large horizontal axis wind turbines is calculated by the blade designer, which is generally more than 40%.As mentioned above, due to the defects of the design method itself, the accuracy of the wind energy utilization rate calculated in this way is questionable.Of course, the wind power curve of the wind turbine in the wind power plant will be drawn according to the measured wind speed and output power. However, the wind speed at this time is the wind speed measured by the wind meter at the rear of the wind wheel. See, if it is less than the incoming wind speed, the wind power curve is high, and must be corrected.After applying the correction method, the wind energy utilization rate of the horizontal axis will be reduced by 30%~50%.For the wind energy utilization rate of small horizontal axis wind turbines,China Aerodynamics Research and Development CenterHave done relevantWind tunnel experimentThe measured utilization rate is 23%~29%.
Structural characteristics
During the rotation of the horizontal axis wind turbine blade, the direction of inertia force changes at any time due to the combined effect of inertia force and gravity, while the direction of gravity remains unchanged, so the blade is subjected to an alternating load, which is very unfavorable to the fatigue strength of the blade.In addition, the generators with horizontal shafts are all located dozens of meters high, which brings a lot of inconvenience to the installation, maintenance and overhaul of generators.
The force on the blades of the vertical axis wind turbine during rotation is much better than that on the horizontal axis. Since the direction of inertia force and gravity is always the same, the fatigue life of the blades is longer than that of the horizontal axis wind turbine due to the constant load.At the same time, the generator with vertical axis can be placed under the wind turbine or on the ground for easy installation and maintenance.
Starting wind speed
Horizontal axis wind wheelThe starting performance of is good, but according toChina Aerodynamics Research and Development CenterFor small horizontal axis wind turbineWind tunnel experimentIt can be seen that the starting wind speed is generally between 4~5m/s, and the maximum is 5.9m/s. This starting performance is obviously unsatisfactory.It is also a consensus in the industry that the starting performance of the vertical axis wind turbine is poor, especially for the Darrieus Ф type wind turbine, which has no self starting ability at all, which is also a limitationVertical axis wind turbineOne reason for application.However, for Darrieus H-type wind turbine, there are opposite conclusions.According to the author's research, as long as the airfoil and installation angle are selected properly, quite good starting performance can be achieved. According to the wind tunnel experiments of double turbine vertical axis wind turbine, vertical axis wind turbine and squirrel cage vertical axis wind turbine, the starting wind speed of this Darrieus H-type wind turbine only needs 2m/s, which is superior to the horizontal axis wind turbine mentioned above.
maintain
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Ordinary maintenance
1. Check, clean and lubricate all rotating parts once a year;
2. The steel wire rope, rigging and all fastening connections shall be cleaned and coated with antirust oil before the rainy season every year;
3. Lubricate and maintain the generator bearing every year;
4. Clean, derust and paint all outdoor parts of wind turbine every two years.
High quality maintenance
1. The outdoor parts are made of stainless steel or undergo special long-term anti-corrosion treatment, so it is unnecessary to maintain the appearance;
2. The generator adopts advanced bearings and advancedLithium greaseCheck the bearing after 5 years of operation, and replenish lubricating grease if necessary.
Application expansion scheme
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Application scenarios
The main application fields of distributed wind power generation system: it can be built in rural areas, pastoral areas, mountainous areas, developing large, medium and small cities or near commercial areas to meet the power demand of local users.
Solution
Distributed wind power generationThe principle 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 existing windmill technology, the power generation can be started at a breeze speed of about three meters per second (the degree of breeze).Wind power generation is becoming an upsurge in the world becauseWind power generationNo fuel is required and no radiation or air pollution is generated.The system is mainly composed of wind turbinesBattery, controllerGrid connected inverterform.
Closed power transmission slip ring, and the cable is not twisted;
It has the characteristics of corrosion prevention, acid rain prevention, salt and alkali prevention;
Micro fan, 2.5 level wind power storage;
The service life is up to 15 years;
With wind direction adjustment and super strong wind control function;
Over charge and over discharge protection, DC constant voltage charging;
Simple operation, no manual watch and special maintenance;
The actual floor area is small, and the land requirement is low. It can be used in harsh terrain conditions such as hills, seashore, river banks, deserts, etc;
The wind wheel not only has but also adds a variety of artistic shapes of vertical and wind blades.
Relevant national policies
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Issued by the National Development and Reform Commission
All provinces, autonomous regions, municipalities directly under the Central Government and cities specifically designated in the state plan, the Development and Reform Commission of Xinjiang Production and Construction Corps, the Energy Bureau, Huaneng, Datang, Guodian, Huadian and China Power Investment Corporation,State Grid Corporation of China、China Southern Power Grid CorporationCGN and CECEP,National Development and Investment Corporation, PetroChina, Sinopec Group Corporation, CNOOC, Shenhua, China Coal Group Corporation, and China United Coalbed Methane Corporation:
In order to promote the application of distributed generation and promote the development of energy conservation, emission reduction and renewable energy, the Commission has organized and formulated《Interim Measures for Distributed Generation Management》。It is hereby printed and distributed to you. Please implement it accordingly.
Development and Reform Commission
July 18, 2013
Interim Measures for Distributed Generation Management
Article 2 The term "distributed power generation" as mentioned in these Measures refers to the power generation facilities that are built, installed and operated on the user's site or nearby in a way that is mainly for the user's own use, with excess electricity connected to the grid, and characterized by balanced regulation in the distribution network system, or the integrated cascade utilization of multi generation facilities with power output.
Article 3 The Measures are applicable to the following distributed generation modes:
（1） Small hydropower stations with a total installed capacity of 50000 kW or less;
（2） Wind energy, solar energy, biomass energy, ocean energy, geothermal energy and other new energy power generation connected to the distribution network at various voltage levels;
（3） In addition to the direct combustion of coal, various waste power generation, multiple energy complementary power generation, residual heat and residual gas power generation, coal mine gas power generation and other resources are comprehensively utilized for power generation;
（4） Coal bed methane power generation with a total installed capacity of 50000 kW or less;
（5） Natural gas, heat, power and cold cogeneration with comprehensive energy utilization efficiency higher than 70% and local power consumption.
Article 4 Distributed power generation should follow the principle of adapting measures to local conditions, clean and efficient, decentralized distribution and local utilization, make full use of local renewable energy and comprehensive utilization of resources, replace and reduceFossil energyConsumption.
Article 5 An open and fair market competition mechanism shall be implemented in the investment, design, construction, operation and other aspects of distributed generation according to law.Distributed power generation project shall meet relevant management requirements to ensure project quality and production safety.
Article 6 The competent energy department of the State Council shall, together with relevant departments, formulate national policies on distributed power generation industry, issue technical standards and engineering specifications, and guide and supervise the management of development planning, construction and operation of distributed power generation in various regions.
Chapter II Resource Evaluation and Comprehensive Planning
Article 7 The fields of developing distributed generation include:
（1） Various enterprises, industrial parks, economic development zones, etc;
（2） Buildings or facilities of government agencies and institutions;
（3） Public buildings or facilities such as cultural, sports, medical, educational and transportation hubs;
（4） Commercial buildings or facilities such as shopping malls, hotels and office buildings;
（5） Urban residential quarters, residential buildings and independent residential buildings;
（6） Villages and towns in rural areas;
（7） Remote farming and pastoral areas and islands;
（8） It is suitable for other fields of distributed generation.
Article 8 Technologies applicable to distributed generation include:
（1） Integrated technology of small hydropower generation, supply and use;
（2） User side photovoltaic power generation technology combined with buildings;
（3） Grid connected wind power and solar power generation technology with decentralized layout;
（4） Multi energy complementary power generation technology such as small wind and solar storage;
（5） Industrial waste heat, pressure and gas power generation and multi generation technology;
（6） Gasification, direct combustion, biogas power generation and multi generation technologies with agricultural and forestry residues, livestock and poultry breeding wastes, organic wastewater and domestic garbage as raw materials;
（7） Geothermal energy, marine energy power generation and multi generation technology;
（8） Multi supply technology of natural gas, coalbed methane (coal mine gas) power generation technology;
（9） Other distributed generation technologies.
Article 9 The provincial competent energy department shall, together with relevant departments, investigate and evaluate the resources available for distributed power generation, so as to provide a scientific basis for the preparation of distributed power generation planning and project construction.
Article 10 The provincial competent energy department, together with relevant departments, shall, according to the resources available for distributed power generation and the local energy demand, prepare a comprehensive plan for distributed power generation in the province, autonomous region and municipality directly under the Central Government, define the development goals, construction scale and overall layout of each key field of distributed power generation, and submit it to the competent energy department of the State Council for the record.
Article 11 The comprehensive planning of distributed generation should be linked with the overall planning of economic and social development, urban planning, natural gas pipeline network planning, distribution network construction planning and power construction planning in areas without electricity.
Chapter III Project Construction and Management
Article 12 Enterprises, specialized energy service companies and various power users, including individuals, are encouraged to invest in the construction and operation of distributed generation projects, and the generation business license of distributed generation projects is exempted.
Article 13 All provincial investment departments and energy departments shall organize and implement the construction of distributed power generation in their own regions.According to the principle of simplifying procedures and improving efficiency, hierarchical management is implemented.
Article 14 The competent energy department of the State Council shall organize the construction of distributed power generation demonstration projects, promote the development of distributed power generation and innovation of management methods, and promote technological progress and industrialization.
Chapter IV Grid Access
Article 15 The competent energy department of the State Council shall, in conjunction with relevant parties, formulate technical standards, engineering specifications and relevant administrative measures for the access of distributed generation to distribution networks.
Article 16 Power grid enterprises shall be responsible for the investment and construction of external grid connection facilities for distributed generation and the transformation of public grids caused by the access, provide convenient, timely and efficient access to power grids for distributed generation, and sign grid connection agreements and power purchase and sale contracts with project units (or self-employed, household users) investing in and operating distributed generation facilities.
Article 17 Power grid enterprises shall formulate the work flow of distributed generation grid connection, set up and publish the location and contact information of receiving the declaration of distributed generation investors in cities or counties, so as to improve service efficiency and ensure barrier free access.
For the distributed generation connected to the distribution network with a voltage level of 35kV or below, the power grid enterprise shall handle the grid connection application according to the specially set simplified process, and provide consulting, commissioning, grid connection acceptance and other services.
For small hydropower stations and distributed power generation connected to the distribution network with a voltage level of more than 35 kV, the grid enterprises should do a good job in grid connection management and provide relevant services in accordance with their access mode, power consumption range, and the principle of simplicity, timeliness and efficiency.
Article 18 Encourage the construction of smart grids and microgrids in combination with distributed power generation applications to improve the utilization efficiency and safe and stable operation level of distributed energy.
Article 19 The agency of the competent energy department of the State Council shall be responsible for establishing a mechanism for supervision of distributed generation and settlement of grid connection disputes, so as to effectively protect the rights and interests of all parties.
Chapter V Operation Management
Article 20 The implementation of grid connection agreements and power purchase and sale contracts related to distributed generation, as well as the purchase and adjustment of excess on grid energy, shall be coordinated by the agency of the competent energy department of the State Council in conjunction with the competent energy department at the provincial level, or entrusted to the subordinate departments.
If the distributed generation involves the adjustment of the power supply business scope, the agency of the energy competent department of the State Council and the provincial energy competent department shall clarify it in accordance with relevant laws and regulations.
Article 21 Distributed power generation is mainly for self use. The surplus electricity is connected to the grid, and the power grid adjusts the surplus and shortage.The two-way metering electricity settlement or net electricity settlement shall be adopted, and the peak and valley electricity price factors can be considered.The settlement cycle shall be determined in the contract and settled monthly in principle.Power grid enterprises shall ensure the priority of grid connection and full purchase of distributed generation surplus electricity.
Article 22 The agency of the competent energy department of the State Council shall, together with the competent energy department at the provincial level, organize the establishment of the monitoring, statistics, information exchange, information disclosure and other systems of distributed generation, and may entrust power grid enterprises to undertake the relevant information statistics. The distributed generation project units (or self-employed, household users) shall cooperate in providing relevant information.
Article 23 Distributed generation investors shall establish and improve operation management rules and regulations.All investors, including individuals and household users, are obliged to cooperate or participate in operation and maintenance under the guidance of power grid enterprises to ensure the safe and reliable operation of the project.
Article 24 The grid connected access points of distributed generation facilities shall be equipped with electric energy metering devices to meet the settlement needs of the on grid energy.Power grid enterprises are responsible for the management of electric energy measurement.
During the operation of distributed generation, complete energy output and fuel consumption measurement data shall be saved.
Article 25 Project units, individuals and household users with distributed generation facilities shall accept the supervision and inspection of the competent energy department and relevant departments, and truthfully provide operation records including original data.
Article 26 Distributed generation shall meet the quality requirements of power generation and supply, and the operation management shall meet the requirements of relevant technology, management regulations and regulations.
The power grid and power operation management organization shall give priority to ensuring the normal operation of distributed generation.Conditional distributed generation shall accept and obey the emergency dispatching of power operation management organization in case of emergency.
Chapter VI Policy Guarantee and Measures
Article 27 According to relevant laws, regulations and policies, construction fund subsidies or unit power generation subsidies shall be given to qualified distributed generation.The construction fund subsidy is limited to the general service scope of power.Those who enjoy construction fund subsidies will no longer be given subsidies for unit power generation.
The subsidized distributed power generation includes wind power generation, solar power generation, biomass power generation, geothermal power generation, marine energy power generation and other new energy power generation.Other subsidy policies for distributed generation shall be implemented according to relevant regulations.
Article 28 The State shall provide financial support for distributed power generation in rural areas, pastoral areas, remote areas and islands, as well as scientific and technological research, standard formulation and demonstration projects of distributed power generation.
Article 29 Strengthen the popularization of science and technology and the publicity of public opinion, and create a social atmosphere conducive to accelerating the development of distributed power generation.
Chapter VII Supplementary Provisions
Article 30 The provincial competent energy departments, together with the agencies of the competent energy department under the State Council and the competent departments in charge of pricing and finance, shall formulate detailed rules for the implementation of distributed generation management in accordance with these Measures.
Article 31 These Measures shall come into force as of the date of promulgation.
market potential
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Since the second half of 2008, influenced by the international macro situation, China's economic development has slowed down.In order to strongly stimulate domestic demand and maintain steady and rapid economic and social development, the government has increased investment in fixed assets in transportation and energy fields, and supported and encouraged the development of renewable energy.As a new energy for energy conservation and environmental protection, the wind power industry has won historic development opportunities.In order to comprehensively promote the economic and social development, some regions that still have shortcomings and have no power residents accelerated the development of small wind power, increased investment in solving the problem of power supply difficulties in remote areas, and strongly promoted the further promotion of small wind power.
The development prospect of China's wind power and other new energy power generation industries is very broad, and it is expected to maintain rapid development for a long time in the future.With the localization of wind power equipment in China,Wind solar complementary systemWith the maturity of new technologies, the cost of small wind power generation is expected to fall again, and the economic and social benefits are improved. The market potential of small wind power generation is huge.Small wind turbine related equipment manufacturing, small wind power technology research and development, wind circuit lights and other fields have become hot investment, and the market prospect is promising.
