風(fēng)力發(fā)電技術(shù) 畢業(yè)論文外文翻譯

1、外文翻譯：Wind Power Generation Technology Wind is very important and reserves of energy, it is safe, clean, and can provide abundant energy, stability of the stream. Now, use wind power has become the main form of wind, the worlds attention, and the fastest. Wind energy technology is a high-tech; it rel

2、ates more than a dozen of subjects, including meteorology, aerodynamics, structural mechanics, computer technology, electronic control technology, material science, chemistry, electrical engineering, electrical engineering, so the difficulty of a system technology may beyond the difficulty of space

3、technology.First, The division of wind energy technologies:Wind energy technology is divided into large-scale wind power technology and small and medium sized wind power technology, although both are wind energy technology, working principles are the same, the two industries are completely different

4、: specific performance of the policy orientation is different in different markets, different applications, applied technology is different, totally belong to the same kinds of industries in the two sectors. Therefore, in China machinery industry meeting on the wind to large wind power and wind powe

5、r to distinguish between small and medium treated separately. In addition, to meet different market needs, extending of the wind and solar technology has not only promoted the development of small wind power technology, but also for the small wind power opens up new markets. 1. Large-scale wind powe

6、r technology: The technology of large-scale wind power in China still has a certain gap between international.The technology of large-scale wind power technology originated in Denmark and some other European countries, the wind power industry propelled by the government, because of the local wind re

7、source-rich, large-scale wind power technology and equipment ahead of the international development. Our government has also started to boost the development of large-scale wind power technology, and a range of policies to guide industry development. Large-scale wind power technology are for the lar

8、ge-scale wind turbine design, wind turbine applications for large area on the very strict environmental requirements are applied to limited resources, wind energy resource-rich wind field, to accept a variety of perennial bad environment that something was the complex nature of the environment, high

9、 demands on the technology up on the line. Currently large-scale wind power technology in general is not yet ripe, the core technology of large-scale wind power still rely on foreign, national policy guidance to the domestic wind power project launched in various places, like crazy, all over look fo

10、rward to slice. Worthy of the name mad electricity through the wind began to Negative effect and Precaution policy. Although wind power projects have been started, but more as complementary type, complete with independent intellectual property rights of large-scale wind power systems technology and

11、core technology few. The test environment needs to have been a large-scale wind power technology to mature. In addition, the large-scale wind power generation technology and network technology has also improved a number of issues still restrict the development of large-scale wind power technology.2.

12、 The technology of small wind powerThe technology of small wind power in China could compare with the international technology.In 1970s, the small wind power technology in China had been developed which has wind resources for a better situation, including Inner Mongolia, Xinjiang areas, the first sm

13、all wind power technology is widely used in power transmission project to the Township for a one of farmers and herdsmen household power supply, continuously updated as the technology improvement and development, not only alone but also with the combination of complementary optical has been widely u

14、sed in distributed independent power supply. These years as Chinese exports of small and medium wind steadily. Internationally, Chinas small and medium sized wind power technology and wind and solar technology have leapt to international leadership.Small wind power technology is mature and relativel

15、y small by natural resource constraints, distributed independent power as a significant effect not only connected, but also the formation of more stable and reliable combination of optical complementary technologies scenery Moreover, technology is completely self-localization. Both from a technical

16、or price in the international arena are very competitive; with international has now started a small wind power in China brand; wall flower wall Hong has intensified. In the countrys most technical advantages and competitiveness of small and medium wind power has always been forgotten by the governm

17、ent and policy in a corner of reasons, in the early states has been to locate the small and medium sized wind power in Inner Mongolia, Xinjiang, farmers and herdsmen in remote areas to use and return into the agricultural class, low cost, shoddy, low-performance reliability, security, no security of

18、 land mostly sparsely populated areas, most of the domestic market are subject to loss of reliability of large price war; in people subconsciously form a poor understanding of So get national attention and development.Domestic small wind power technology in the low wind start, low wind speed generat

19、ion, pitch moment, multiple protection, and a series of technical attention by the international market and international clients unanimously approved, has a leading position. Moreover, the small and medium Wind power technology is ultimately distributed independent power supply to meet end-market,

20、rather than large-scale wind power generation and network technologies to meet the domestic monopoly market, technology, update rate must be adapted to a broad and rapidly growing market.3. wind and solar technology:Wind is the integration of technical skills and the Small and Medium Wind Energy Sol

21、ar Energy Technology, combines a variety of applications of new technology, and it covers many areas, the wide range of applications, technical differentiation is so great that a variety of techniques which can separate match.Wind and solar power is currently the world in the use of new energy techn

22、ology the most mature, most large-scale and industrial development of the industry, separate and individual solar wind has its drawbacks of development, but both wind and solar power complementary combined to realize the two new configuration of energy in natural resources, the technical programs of

23、 integration, performance and price compared to aspects of the new energy source for the most reasonable, not only reduces the demand to meet under the same unit cost and expand the scope of application of the market, also increases the reliability of the product.In addition: solar and wind power ar

24、e both new energy, solar energy than the wind started to be late more than 30 per solar PV / W by the general public about the price of recognition can be converted to a 15% rate; while the price of small wind power conversion rate is only 1/5-1/6 of the same 60% -80%, only the low price .Worse stil

25、l suppressed, photoelectric production of pollution on the environment greater than wind power, than substantial development in wind energy, this comparison contrast twist of meditation ., if people use the energy from the point of view, our goal is to meet the electricity from wind power generating

26、 capacity to measure the cost of solar energy economy than many.Wind, solar and wind power integration advantages, not only for the energy saving, emission reduction, opened up new horizons for the application of science to meet human needs, for the world to open a fourth revolution.Second，Wind powe

27、r has three kinds of operation mode:One is independent operation mode, usually a small wind generators to one or a few families to provide power, storage battery energy, to ensure the electricity without wind, Second is the wind turbines and other power mode (such as engine power), combining to a un

28、it or an village or an island power supply, Three is wind power into conventional power operate and to provide electric power grid, is often a wind tens or hundreds of sets installed wind generators, this is the main development direction of wind power.Wind power system in the two main parts is wind

29、 machine and generators. Wind turbines to change from adjusting technique, plasma generator toward VSCF technology, this is the development trend of wind power technology is the core technology nowadays wind turbines. The following simple introduction of this two respects.1. the change of wind plasm

30、a from regulationWind turbines impeller, will capture the wind by converting wind effects on the mechanical wheel torque.Change is the change from adjustment with vertical axis wind leaf surface of Angle, thus affecting the force and the blade, when the wind resistance increases, the output power of

31、 the fan is kept constant power output. By regulating mode, fan from the output power curve is smooth. In the rated wind leaf Angle of attack, controller will be placed near zero, do not change, approximate distance equal to adjust for pulp. In the rated wind above, variable structure control functi

32、on from pulp, adjust the blade Angle of attack, the output power control in near ratings. Change from the wind plasma starting from wind speed is set slurry machine downtime at low impact stress relative ease. The normal work, is mainly adopts power control, in practical applications, power and spee

33、d is directly proportional to the set. Small changes will cause the wind changes of wind.Due to the change of wind from pulp by adjusting the impact than other wind from small, can reduce material utilization rate, reduce overall weight. And the change of wind from accommodation type at low speed, c

34、an make the blades, keep good Angle of attack than accommodation type stall wind turbines have better energy output, therefore is suitable for low average speed of the region.Change from another advantage of regulation, when the winds reach a certain value, stall type of wind and downtime, must from

35、 type machine can gradually changes to the wind load without a blades of open mode, avoid wing, increase of wind turbine.Change is to adjust the defect is sensitive response requires gusts. Because the wind accommodation type stall fan vibration power pulse are small, and accommodation type from win

36、d turbines is bigger, especially for the change from the constant speed windmills way, this kind of circumstance, this does not require more obvious change in the fan is the response speed of wind system to fast enough, can reduce this phenomenon.2. The variable speed constant frequency wind turbine

37、Variable speed constant frequency wind turbine type often adopt ac excitation doubly-fed generator, its structure is shown in figure 1. Its structure similar to wound induction motor, just on the rotor winding with slip ring and brush, as a result, the rotor speed related to the excitation frequency

38、, thus, making type doubly-fed generator internal electromagnetic relationship is different from asynchronous generator and is different from the synchronous generator, but it has some characteristics of asynchronous and synchronous machine.Ac excitation doubly-fed variable speed constant frequency

39、wind turbine can not only by controlling the ac excitation amplitude, phase and frequency to realize variable speed constant frequency, can also realize the active and reactive power control, for the grid can also ACTS as reactive power compensation.Third, the development of wind energy technology r

40、equires constant innovation: At present, Chinas wind energy development in technological innovation is still very weak, the lack of core technologies with independent intellectual property. Thus, much would import technology from abroad. Although the arrival of knowledge economy era, all countries t

41、ake full advantage of global resources and international cooperation through the introduction of technology to bridge the gap and improve competitiveness. But if there is no capability of independent innovation, not know what the introduction of advanced technologies, are not able to absorb the futu

42、re, cannot carry out another record, which is on the one hand; on the other hand, the core technology is the introduction of foreign countries cannot, and must be rely on innovation to master the core technology; Moreover, the domestic policy of independent innovation of technology needs to supporti

43、ng, guiding, supporting, with the core technology of wind energy products to be increasing support, such a wall flower wall incense situation can be change, innovation and power can come from constant innovation.In short: the wind power industry continuing to creating in a single generation from win

44、d energy technology to power the various areas of need ,its additional products have emerged such as: street, landscape, traffic control, communication, irrigation, planting, breeding, sea water desalination , fire, alarm, islands, mountains and so on. Shows the development of wind energy in this ne

45、w industry can be brought about numerous development and transformation of traditional industries, but the application of wind energy technology in various fields has become the industrys benchmark. World revolution will be caused by wind energy technology from the New Energy and Industrial revoluti

46、on.Four, Influence of wind power generation on power systems: High penetration of wind power in the power systems faces fundamental technical limits with regard to the integration of large-scale wind farms to the grid. The influence of wind power generation on power systems includes active and react

47、ive power flow, voltage, system stability, power quality, short-circuit capacity, system reserve and infrastructure due to the characteristics of high-capacity, dynamic and stochastic performance of wind power generation. Technically, it influences the gird in the following ways and has to be studie

48、d in detail:Active and Reactive Power FlowWind power is a kind of intermittent and stochastic power source, which will complicate the power flow. Because many wind farms are built far away from load centers in order to capture more wind energy, there is always some obstacle of transmitting wind powe

49、r. Some transmission or distribution lines and other electrical equipments may be over-loaded when the additional wind power generation is introduced. So it should be ensured that the interconnecting transmission or distribution lines will not be over-loaded. Both active and reactive power requireme

50、nts should be investigated. Reactive power should be generated not only at PCC, but also throughout the network, and should be compensated locally.Voltage Regulation Once a wind farm has identified its site, the point at which connection to the grid must be identified. Small wind farm can connect at

51、 lower voltage, thereby saving on switchgear, cable and transformer costs. If the size of the proposed development is too large to be connected at the local distribution voltage, access to the transmission network at a higher voltage is required.After failures, if the transient stability does not oc

52、cur in power systems, some wind turbines shut down due to their low voltage protections. Then outputs of wind farms decrease, which means that the power system lose reactive loads. Therefore the voltage levels climb up, even beyond the upper limits of wind farms buses. Capacitors are the common reac

53、tive power compensation methods. When voltage levels dropdown, the amount of compensation decreases much. However the reactive power demands increase when the asynchronous machines are utilized in wind farms. So voltage levels drop down more, even beyond the lower limits of wind farms buses.With the

54、 increase of wind power installed capacity in power systems, the variability of wind power generation causes variability of voltage level, particularly if integrated into the grid which might not be specifically designed to cater for the significant and possibly rapid load variations (compared with

55、normal customer load variation) caused by highly variable wind power generation. Therefore, the regulatory measures are needed to maintain the voltage level in a specified range. However, the variability of wind power generation is not a low probability; this could result in an increased requirement

56、 for reactive power ancillary services to manage voltage control.System Stability In the power system with high wind power penetration, the transient stability, voltage stability and frequency stability are all influenced by the wind power integration not only because the injection of wind power wil

57、l change the power flow distribution, transferred power of each transmission line and total inertia of the whole power system, but also because the wind turbine generators perform differently in either steady-state or transient-state compared with the conventional synchronous machine. For current op

58、eration of wind farms, protections usually cut off the connections between wind farms and the grid when great disturbances occur. This is equivalent to arouse new generators tripping disturbance after the great disturbances. So the transient stability in such moment is very crucial, especially when

59、large-scale wind farms are integrated. Compared the variable-speed wind turbine based on the doubly-fed induction generator (DFIG) with the fixed-speed wind turbine based on the induction motor, the former is more robust after short-circuit failures and can strengthen system stability with keeping e

60、nough stability margin. However, wind power integration may also make the system transient stability worse due to the grid structure. Therefore, transient stabilities of different power systems should be analyzed respectively.The fixed-speed wind turbine absorbs the reactive power when outputting th