风力发电外文文献翻译中英文
毕业设计风力发电外文文献
Abstract--The purpose of this paper is to find an innovative, high efficiency, practical and low cost control system structure with an optimized control strategy for small-scale grid-connected wind turbine with direct-driven permanent magnet synchronous generator (PMSG). This research adopts the sensorless vector control strategy based on phase-locked loop (PLL) for PMSG control, and the grid-side inverter control strategy is based on the single-phase PLL. The simulation demonstrates that the sensorless control strategy and single-phase grid-side inverter control strategy are practical solutions for grid-connected PMSG wind turbines, and they can provide both generator speed control for optimized wind power tracking and good power quality control for electricity delivered to the grid. The designed system offers many unique advantages, including simple topology, optimized control strategy, cost-effective and fast respond to grid failures.Index Terms--Maximum power point tracking (MPPT), PMSG, pulse-width modulation (PWM) converter, speed control, variable-speed wind turbine.I. I NTRODUCTIONn recent years, great attention has been paid on renewable energy sources, such as wind and solar energy. Wind energy is the most popular renewable energy source due to its relatively low cost. The overall system cost can be further reduced by optimal control of high efficiency power electronic converters to extract maximum power in accordance with atmospheric conditions [11].The wind energy conversion system based on permanent magnet synchronous generator (PMSG) is one of the most favorable and reliable methods of power generation. Reliability of variable-speed direct-driven PMSG wind turbines can be improved significantly comparing to doubly-fed induction generator (DFIG) wind turbines with gearboxes. Noise, power loss, additional cost, and potential mechanical failure are typical problems for a DFIG wind turbine because of the existence of a gearbox. The use of direct-driven PMSG could solve these problems. Moreover, low voltage ride through (LVRT) is also a big issue for DFIG because the This work was supported in part by the special funds from Beijing Municipal Education Commission.Chunxue Wen, Guojie Lu, Peng Wang and Zhengxi Li are with the Power Electronics and Motor Drivers Engineering Research Centre, North China University of Technology,Beijing,China(e-mail: wenchx1980@, lugod307@, catdapeng2008@, lzx@).Xiongwei Liu and Zaiming Fan are with the School of Computing, Engineering and Physical Sciences, University of Central Lancashire, Preston, PR1 2HE, UK (e-mail: xliu9@, zmfan@) electromagnetic relationship between the stator and the rotor is more complex than PMSG. Therefore, it’s more difficult for DFIG to solve LVRT problem safely and reliably.In a variable-speed PMSG system, vector control approach is often used to achieve nearly decoupled active and reactive power control on the grid-side inverter which is a current regulated voltage source inverter. In this way, the power converter maintains the DC-link voltage and improves the power factor of the system [1], [7], [10]. Different control methods for maximum power point tracking (MPPT) in variable-speed wind turbine generators have been discussed in [2], [4], [7].This research adopts the sensorless vector control strategy based on phase-locked loop (PLL) for PMSG control [2]. The method requires only one active switching device, i.e. insulated-gate bipolar transistor (IGBT), which is used to control the generator torque and speed so as to extract maximum wind power. It is a simple topology and low cost solution for a small-scale wind turbine because of the sensorless vector control strategy. The grid-side inverter control strategy is based on the single-phase PLL, which applies a control method in Direct-Quadrature (DQ) rotating frame to single-phase inverter and achieves superior steady state and dynamic performance [6].For small-scale wind turbine, single-phase power supply to consumers is popular. There are many control methods for single-phase inverter, such as PI controller, quasi-PR controller, etc. [5]. However, these methods can’t decouple the active power and reactive power so as to have good power control performance. Single-phase PLL method based on DQ rotating frame can well solve this problem. On the other hand, encoders are vulnerable components for wind turbines, particularly for small wind turbines, because small wind turbines experience severer vibrations than their large counterparts. The sensorless vector control opts out the encoders, and therefore the reliability of wind turbines is much improved. For these reasons, the sensorless vector control and single-phase PLL method have their unique advantages for small-scale wind turbines.This paper is structured further in following three sections. In section II, the principle of the full power back-to-back PWM converter is introduced. Then the vector control of small-scale grid-connected wind power system including sensorless control, vector control of PMSG, single-phase PLL, vector control of grid-side inverter are described in section III. Finally, in section IV, the simulation results and conclusion are given.Vector control strategy for small-scale grid-connected PMSG wind turbine converter Chunxue Wen, Guojie Lu, Peng Wang, Zhengxi Li Member IEEE, Xiongwei Liu Member IEEE,Zaiming Fan Student Member IEEEIII. T HE PRINCIPLE OF FULL POWER BACK-TO-BACK PWMCONVERTERTypical topology model of direct-driven PMSG wind turbine is shown in Fig. 1. Converters of the system adopt back-to-back pairs of pulse-width modulation (PWM) architecture. The generator-side converter controls the generator speed in order to achieve maximum capture of wind power, and the grid-side inverter controls the stability of DC-bus voltage and the power factor of the system. This topology can be a good way to improve performance, and the control method is flexible. Converters have four-quadrant operation function, which can fulfill the generator speed control anddeliver the fine quality of electricity to the grid [7], [8].Fig. 1. Topology of permanent magnet direct-driven wind power systemIII. T HE VECTOR CONTROL OF SMALL-SCALE GRID-CONNECTEDDIRECT-DRIVEN WIND POWER SYSTEM CONVERTERFig. 2 shows the back-to-back PWM voltage convertervector control block diagram. The machine-side PWMconverter controls the electromagnetic torque and statorreactive power (reactive power is often be set to 0) byadjusting the current of the d-axis and q-axis of the machine-side converter. This control mechanism helps the PMSG tooperate in variable speed, so that the wind turbine can workwith maximum power point tracking (MPPT) under the ratedwind speed. The grid-side PWM inverter stabilizes the DC-busvoltage and accomplishes active and reactive decouplingcontrol by adjusting the current of the d-axis and q-axis of thegrid-side. The grid-side PWM inverter also controls thereactive power flow to the grid, usually at unity power factorcondition.A. Sensorless control based on PLLThe speed and position control is achieved throughsensorless vector control of the machine-side converter basedon all-digital phase-locked loop. The phase-locked loop isdesigned to control the frequency of the D-Q axis voltagethrough minimizing the difference of the output voltage phaseangle and the given voltage phase angle, until the outputvoltage phase angle tracks the given voltage phase angle. Asthe phase-locked loop has frequency closed-loop trackingmechanism, the generator voltage frequency and the anglebetween d-axis voltage and rotor flux can be measured withthis characteristic, then the generator speed and rotor positionangle can be derived [2]. The control accuracy is generallygood using this method, however some problems may occurwhen the generator operates at very low speed. The windpower system often works above the cut-in wind speed, so thismethod can be applied to wind power generation system.Fig. 2.The back-to-back PWM voltage converter vector control block diagramThe actual rotor position of PMSG is indicated in the D-Q coordinate system. The estimated location for ∧θ is the d q ∧∧− coordinate system, αβ is the stationary coordinate system, as shown in Fig. 3. As the rotor position of PMSG is estimated rather than measured in the sensorless vector control system, there exists an error θΔ between the actual rotor position θ and the estimated location ∧θ. At the same time, the back-EMF (electromotive force) generated by the rotor permanent magnets generates two d-axis and q-axis components in the estimated rotor position orientation coordinates, which are expressed as sd e ∧and sq e ∧respectively. Conventional PI controller can achieve zero error control, i.e. sd e ∧or θΔ can be adjusted to zero value. The PLL sensorless vector control schematic diagram is shown in Fig. 4, and the value of sd e ∧and sq e ∧can be obtained from (1).sd sd s sd dq sq sd sq sq s sq q d sd sq di u R i L L i e dt di u R i L L i e dt ωω∧∧∧∧∧∧⎧=+−−⎪⎪⎨⎪=+++⎪⎩(1)Fig. 3. Presumed rotating coordinate systemFig. 4. Principle of PLL based sensorless vector controlIf we ignore the current differential items in (1), then wehavesd s sd q sq sd sq sq s sq d sd ˆˆˆˆˆarctan(arctan(ˆˆˆˆˆu R i L i ee uR i L i ωθω−+Δ=−=−−− (2)where sd u , sq u , sd i and sq i are the d, q-axis components of the output voltage and current of the generator stator; d L q L and s R are the inductance and resistance of the stator; ω is thegenerator electrical angular velocity of the generator; "∧" indicates estimated value.Block diagram of sensorless vector control based on digital PLL is shown in Fig. 5. The back-EMF (electromotive force) value of the estimated rotating coordinates can be obtained by calculating the three-phase voltages and currents of the PMSGstator. The calculated angle difference θΔcan be used to estimate the angular velocity through the PI controller. Then the value of the estimated angle can be obtained by integral element. Generally, the speed has considerable fluctuations using this method. Therefore it will achieve a better estimation by adding a low-pass filter (LPF), as shown in Fig. 5.∧Fig. 5. Block diagram of sensorless vector control based on digital PLLB. Vector control of PMSGIn order to study the torque control of PMSG, it is necessary to establish a mathematical model. Because q-axis leads d-axis 90° in the D-Q coordinate system, the generator voltage equation can be expressed as [8]: sd sd s sd d sq sq sq sq sq q d sd di u R i L L i dt di u Ri L L i dt ωωωψ⎧=+−⎪⎪⎨⎪=+++⎪⎩(3) The significance of various physical quantities in (3) is the same as in (1).The generator electromagnetic torque equation can be expressed as:33()22e sq d q sd sq T p i p L L i i ψ=+− (4) where p is the number of generator pole pairs, and ψ is the magnetic flux.Based on the above mathematical model, the sensorless vector control program of PMSG is established, and its controlblock diagram is shown in Fig. 6.sa i sbi Fig. 6. Sensorless vector control block diagram of PMSGGenerator rotor position and speed which are estimated by sensorless algorithm can be used in vector control. Thereference value of motor torque can be obtained by the speedcontroller. The voltage reference of generator can also be gotby current controller, and then the control signals of rectifier switching device can be obtained by a set of PWM modulation algorithms. The position and speed of generator rotor which is necessary to vector control is obtained by sensorless algorithm.C. Single-phase grid-connected PLLFig. 7 shows the block diagram of the single-phase gird-connected PLL. In order to ensure that the converter outputvoltage is in the same phase with the output current, the PLLis used to achieve unity power factor control. At the sametime, the converter also provides the angle of the referencecurrent transformation [5].Fig. 7. The block diagram of the single-phase PLLThe transformation between orthogonal a-b and D-Q reference frames can be described by trigonometric relations, which are given in (5) and (6), and the rotating reference frame is shown in Fig. 8.Fig. 8. Definition of rotating reference frame⎥⎦⎤⎢⎣⎡⎥⎦⎤⎢⎣⎡−=⎥⎦⎤⎢⎣⎡b a q d f f f f θθθθcos sin sin cos (5) ⎥⎦⎤⎢⎣⎡⎥⎦⎤⎢⎣⎡−=⎥⎦⎤⎢⎣⎡q d b a f f f f θθθθcos sin sin cos (6)Active power and reactive power equations can beexpressed as:⎩⎨⎧−=+=d q q d qq d d i v i v Q i v i v P (7) If the phase voltage and q-axis coincide, then 0=d v andv v q =, active power and reactive power equations can besimplified as:||||q dP v i Q v i =⎧⎪⎨=−⎪⎩ (8) D. The vector control strategy of the grid-side inverterFor a three phase converter, simple PI compensators designed in a D-Q synchronous frame can achieve zero steady state error at the fundamental frequency, but this method is not applicable to single-phase power converter because there is only one phase variable available in a single-phase power converter, while the D-Q transformation needs at least two orthogonal variables.In order to construct the additional orthogonal phaseinformation from the original single-phase power converter,the imaginary orthogonal circuit is developed, as shown inFig. 9. The imaginary orthogonal circuit has exactly the samecircuit components and parameters, but the current b i and the voltage b e , maintain 90D phase shift with respect to their counterparts in the real circuit- a i and a e [6].Fig. 9. Real circuit and its imaginary orthogonal circuitFrom Fig. 9, the voltage equation can be expressed as:⎥⎦⎤⎢⎣⎡−−+⎥⎦⎤⎢⎣⎡⎥⎦⎤⎢⎣⎡−=⎥⎦⎤⎢⎣⎡b b a a b a b a v e v e L i i L R i i p 11001 (9) Transforming the voltage equations into the synchronousreference frame using (5) and (6), and considering 0=d v and v v q =, we have: ⎥⎦⎤⎢⎣⎡−+⎥⎦⎤⎢⎣⎡⎥⎦⎤⎢⎣⎡−−−=⎥⎦⎤⎢⎣⎡||1//v e e L i i L R L R i i p qd q d q d ωω (10) To achieve decoupled control of active power and reactive power, the output voltage of the inverter in the synchronousreference frame can be expressed as:||)(1v i x L e d q +−=ω (11))(2q d i x L e ω+= (12)Substituting (11) and (12) into (10), system equations canbe rewritten as follows:⎥⎦⎤⎢⎣⎡+⎥⎦⎤⎢⎣⎡⎥⎦⎤⎢⎣⎡−=⎥⎦⎤⎢⎣⎡211001x x i i L R i i p q d q d (13) The active power and reactive power could be controlled by d i and q i respectively. Therefore, system control can be completed by current feedback loops as follows:))((211q q i i s k k x −+=∗(14)))((212d d i i sk k x −+=∗(15) Fig. 10 shows the control block diagram of the grid-sideinverter. It should be noted that the given active and reactive power should be set at two times of the desired values, because the imaginary circuit will not deliver any active andreactive power to the grid.θωFig. 10. The vector control block diagram of the grid-side inverterIV. S IMULATION RESULTSA simulation model in Matlab/Simulink is developed based on above theoretical analysis, and the system simulation block diagram is shown in Fig. 11.Fig. 11. The system simulation block diagramA. The simulation results of the machine-side converterIn the simulation model, the Reference speed represents the wind speed. At the beginning of the simulation (i.e. 0s), the generator speed is 4rpm and its input torque is -50Nm. At the time of 0.5s, the generator speed is 17 rpm and the input torque maintains at the value of -50Nm. At 1s, the generator speed maintains at 17 rpm and the input torque is -80Nm. The simulated waveforms are shown in Fig. 12, Fig. 13, Fig. 14, Fig. 15, respectively.It can be seen from Fig. 12 and Fig. 13, the error between the estimated rotor position angle and the actual measurement of the rotor position angle is very small in the steady state, there are some fluctuations in the dynamic response, but the rotor position angle is stabilized quickly.It can be seen from Fig. 14 and Fig. 15, there is a small error between the estimated and measured generator rotor speed at low speed. At high speed, however, the error is very small and can be ignored, and the transient response is very short. At the time 1s, the input torque increase affects thegenerator rotor speed slightly, and soon the transientdisappears.ˆ,(d e g )θθ()t sFig. 12. The estimated and measured rotor position angle(rad/s)θθ∧−(s)tFig. 13. The error of estimated and measured rotor position anglet(s)()nrpmFig. 14. The measured generator rotor speedt(s)t()esirpmnFig. 15. The estimated generator rotor speedThe simulation waveforms of the machine-side converterdemonstrate that the sensorless vector control algorithm canestimate the rotor angular position accurately, and the vectorcontrol strategy of the machine-side converter can realizegenerator speed control for the wind turbine to follow theoptimized power curve, i.e. MPPT when the wind speed isbelow rated wind speed.B. The simulation results of the grid-side inverterThe simulation results of the grid-side inverter is shown inFig. 16, Fig. 17 and Fig. 18 respectively.It can be seen from Fig. 16, when the generator outputtorque increases, the DC bus voltage is maintained constant.Fig. 17 shows that θu followsavvery well, and Fig. 18shows thatai followsavvery well.Fig. 16. The simulated DC voltageavuθuθFig. 17. The generator output A phase voltage and the grid voltage vectorangleFig. 18. The output voltage and current of the grid-side inverterFrom the simulation results of the grid-side inverter, it canbe seen that the single-phase PLL algorithm can accuratelytrack the grid-side voltage, and the vector control strategy ofthe grid-side inverter can stabilize the DC bus voltage, andcontrol the grid power factor.V. C ONCLUSIONThis research developed a power electronic converter for asmall direct-driven PMSG wind turbine using the back-to-back pulse-width modulation (PWM) topology. Thesimulation results demonstrate that1) The machine-side converter can control the generatorspeed and torque for the wind turbine to follow the optimizedpower curve, i.e. maximum power point tracking (MPPT)when the wind speed is below rated wind speed.2) The sensorless phase-locked loop (PLL) controlalgorithm can realize the vector control of the generator.3) The grid-side inverter control algorithm based on single-phase PLL can stabilize the DC bus voltage of the converter and control the grid power factor.VI. R EFERENCESPeriodicals:[1]De Tian, “The wind power technology status and development trend inthe world,” New Energy Industry, in press.[2]Ruzhen Dou, Lingyun Gu, Baotao Ning, “Sensorless control of thePMSM based on the PLL,” Electric Machines & Control Application, vol. 32, pp. 53-57, 2005.Books:[3]Qingding Guo, Yibiao Sun, Limei Wang, Modern permanent magnet ACservo motor system. China Electric Power Press, Beijing. In press.Papers from Conference Proceedings (Published):[4]S. Song, S. Kang, and N. Hahm, “Implementation and control of gridconnected AC-DC-AC power converter for variable speed wind energy conversion system,” in Proc. 2003 IEEE Applied Power Electronics Conference and Exposition, vol.1, pp.154 – 158.[5]M. Ciobotaru, R. Teodorescu and F. Blaabjerg, “A new single-phasePLL structure based on second order generalized integrator,” Record of IEEE PESC 2006, Korea, pp.1511-1516.[6]R. Zhang, M. Cardinal, P. Szczesny, M. Dame, “A grid simulator withcontrol of single-phase power converters in D-Q rotating frame,” Power Electronics Specialists Conference, vol.3, pp.1431 – 1436, 23-27 June 2002.[7]R. Esmail, L. Xu, D.K. Nichols, “A new control method of permanentmagnet generator for maximum power tracking in wind turbine application,” IEEE Power Engineering Society Meeting, vol.3, pp. 2090-2095, August 2005.[8]Yang Zhenkun, Liang Hui, “A DSP control system for the gridconnected inverter in wind energy conversion system,” IEEE ICEMS 2005 Electrical Machines and Systems, vol. 2, 2005, pp. 1050-1053, June 2005.[9]N V Suresh Kumar Srighakollapu, Partha Sarathi Sensarma, “Sensorlessmaximum power point tracking control in wind energy generation using permanent magnet synchronous generator,” Industrial Electronics 2008, 34th Annual Conference Of IEEE, Iecon , pp.2225-2230.Dissertations:[10]Cheng Lu, “The coordination control of dual PWM converter for VSCFwind power generation system,” MSc thesis, Graduate School of Chinese Academy of Sciences, Beijing, 2004.[11]Shenbing Wu, “Research on CSC-based small-scale grid-connectedwind power generation system”, MSc thesis, Hefei University of Technology, Hefei, 2009.VII. B IOGRAPHIESChunxue Wen received his BSc degree from Inner Mongolia University of Technology in 2001, MSc degree from Wuhan University in 2006, and PhD degree from the Institute of Electrical Engineering, Chinese Academy of Sciences in 2009. In 2010 he joined the Wind Energy Engineering Research Group at the University of Central Lancashire as a visiting researcher. He is currently working as a Lecturer at the Power Electronics and Motor Drivers Engineering Research Center, North China University of Technology, Beijing, China. His research interests include power electronics, wind turbine control system, converters for wind turbines.Guojie Lu received his BSc degree from North China Electric Power University in 2006. He worked in Beijing Xinhuadu Special Transformer Company from 2007 to 2009, and was responsible for the technical service transformer. At present, he is registered as a postgraduate research student at the Power Electronics and Motor Drivers Engineering Research Center, North China University of Technology, Beijing, China. His research area is wind turbine control system.The project aims to develop maximum power point tracking control algorithm for grid-connected small wind turbines.Peng Wang received his BSc degree from Taiyuan University of Technology in 2003, MSc degree from North China University of Technology in 2011. Since 2008, he has been working as a research assistant in Electrical Engineering at the Power Electronics and Motor Drivers Engineering Research Center, North China University of Technology, Beijing, China. In 2010 he joined the Wind Energy Engineering Research Group at the University of Central Lancashire as a visiting student. His research areas are permanent-magnet synchronous generator control and wind energy engineering.Zhengxi Li received his PhD degree from the University of Science and Technology, Beijing. He is the Chair Professor in Power Electronics and Motor Drivers and Head of the Power Electronics and Motor Drivers Engineering Research Center, North China University of Technology, Beijing, China. He is also Vice President of North China University of Technology. His research interests include power electronics, high voltage power transmission and distribution, intelligent transportation and renewable energy. Xiongwei Liu was born in Xiangtan, China, in 1965. He received his BEng (Hons) degree from National University of Defense Technology, Changsha, in 1985, and his MSc (Distinction) and PhD degrees from Harbin Institute of Technology in 1988 and 1991 respectively.His employment experience included Northwestern Polytechnical University, Huaqiao University, Leeds Met University, University of Hertforshire and University of Central Lancashire. His research interests include wind energy engineering, renewable energy technologies, smart grid and microgrid, and intelligent energy management system.He received a research fellowship from Alexander-von-Humboldt Foundation of Germany, which allowed him to visit Ruhr University Bochum, as a research fellow for 18 months from 1993. In 1999 he was awarded a Bronze Medal by Huo Yingdong Education Funding Council and a Model Worker Medal by the Mayor of Quanzhou, China, due to his excellent contributions in higher education when he served as a professor at Huaqiao University. He received a research fellowship from Chinese Scholarship Council, which allowed him to visit Technical University Berlin as a senior research fellow for 6 months in 2000.Xiongwei Liu is currently working as Chair Professor of Energy and Power Management and Head of Wind Energy Engineering Research Group at the University of Central Lancashire.。
风力发电英文作文
风力发电英文作文Wind power generation is a clean and renewable energy source that harnesses the power of the wind to generate electricity. It is a sustainable alternative to traditional fossil fuels and has the potential to reduce greenhouse gas emissions and combat climate change.The use of wind turbines to capture the kinetic energyof the wind and convert it into electricity has beengrowing rapidly in recent years. Wind power generation has the advantage of being able to produce electricity without the release of harmful pollutants or greenhouse gases, making it an environmentally friendly energy source.One of the key benefits of wind power generation is its ability to provide electricity to remote and off-grid areas. Wind turbines can be installed in locations wheretraditional power infrastructure is not available, bringing electricity to communities that would otherwise havelimited access to energy.In addition to its environmental benefits, wind power generation also has the potential to create jobs and stimulate economic growth. The development, installation, and maintenance of wind turbines require skilled labor, creating employment opportunities in the renewable energy sector.Despite its many advantages, wind power generation also faces challenges. One of the main challenges is the intermittent nature of wind energy, as the wind does not blow consistently. This variability in wind speed can make it difficult to rely solely on wind power generation for electricity supply.In conclusion, wind power generation is a promising and sustainable energy source that has the potential to play a significant role in the transition to a low-carbon economy. With ongoing technological advancements and investment in wind energy infrastructure, it is likely to become an increasingly important part of the global energy mix.。
风力发电外文文献翻译中英文
风力发电外文翻译中英文英文Wind power in China – Dream or reality?HubacekAbstractAfter tremendous growth of wind power generation capacity in recent years, China now has 44.7 GW of wind-derived power. Despite the recent growth rates and promises of a bright future, two important issues - the capability of the grid infrastructure and the availability of backup systems - must be critically discussed and tackled in the medium term.The study shows that only a relatively small share of investment goes towards improving and extending the electricity infrastructure which is a precondition for transmitting clean wind energy to the end users. In addition, the backup systems are either geographically too remote from the potential wind power sites or currently financially infeasible. Finally, the introduction of wind power to the coal-dominated energy production system is not problem-free. Frequent ramp ups and downs of coal-fired plants lead to lower energy efficiency and higher emissions, which are likely to negate some of the emission savings from wind power.The current power system is heavily reliant on independentlyacting but state-owned energy companies optimizing their part of the system, and this is partly incompatible with building a robust system supporting renewable energy technologies. Hence, strategic, top-down co-ordination and incentives to improve the overall electricity infrastructure is recommended.Keywords: Wind power, China, Power grids, Back-up systems1. IntroductionChina 'wsi nd energy industry has experienced a rapid growth over the last decade. Since the promulgation of the first Renewable Energy Law in 2006, the cumulative installed capacity of wind energy amounted to 44.7 GW by the end of 2010 [1]. The newly installed capacity in 2010 reached 18.9 GW which accounted for about 49.5% of new windmills globally. The wind energy potential in China is considerable, though with differing estimates from different sources. According to He et al. [2], the exploitable wind energy potential is 600–1000 GW onshore and 100–200 GW offshore. Without considering the limitations of wind energy such as variable power outputs and seasonal variations, McElroy et al. [3] concluded that if the Chinese government commits to an aggressive low carbon energy future, wind energy is capable of generating 6.96 million GWh of electricity by 2030, which is sufficient to satisfy China ' selectricity demand in 2030.The existing literature of wind energy development in China focuses on several discussion themes. The majority of the studies emphasize the importance of government policy on the promotion of wind energy industry in China [4], [5], [6], [7]. For instance, Lema and Ruby [8] compared the growth of wind generation capacity between 1986 and 2006, and addressed the importance of a coordinated government policy and corresponding incentives. Several studies assessed other issues such as the current status of wind energy development in China [9]; the potential of wind power [10]; the significance of wind turbine manufacturing [11]; wind resource assessment [5]; theapplication of small-scale wind power in rural areas [12]; clean development mechanism in the promotion of wind energy in China [4], social, economic and technical performance of wind turbines [13] etc.There are few studies which assess the challenge of grid infrastructure in the integration of wind power. For instance, Wang [14] studied grid investment, grid security, long-distance transmission and the difficulties of wind power integration at present. Liao et al. [15] criticised the inadequacy of transmission lines in the wind energy development. However, webelieve that there is a need to further investigate these issues since they are critical to the development of wind power in China. Furthermore, wind power is not a stand-alone energy source; it needs to be complemented by other energy sources when wind does not blow. Although the viability and feasibility of the combination of wind power with other power generation technologies have been discussed widely in other countries, none of the papers reviewed the situation in the Chinese context. In this paper, we discuss and clarify two major issues in light of the Chinese wind energy distribution process: 1) the capability of the grid infrastructure to absorb and transmit large amounts of wind powered electricity, especially when these wind farms are built in remote areas; 2) the choices and viability of the backup systems to cope with the fluctuations of wind electricity output.2. Is the existing power grid infrastructure sufficient?Wind power has to be generated at specific locations with sufficient wind speed and other favourable conditions. In China, most of the wind energy potential is located in remote areas with sparse populations and less developed economies. It means that less wind powered electricity would be consumed close to the source. A large amount of electricity has to be transmittedbetween supply and demand centres leading to several problems associated with the integration with the national power grid system, including grid investment, grid safety and grid interconnection.2.1.P ower grid investmentAlthough the two state grid companies-(SGCC) State Grid Corporation of China and (CSG) China Southern Grid - have invested heavily in grid construction, China 'pso wer grid is still insufficient to cope with increasing demand. For example, some coal-fired plants in Jiangsu, which is one of the largest electricity consumers in China, had to drop the load ratio to 60 percent against the international standard of 80 percent due to the limited transmission capacity [16]. This situation is a result of an imbalanced investment between power grid construction and power generation capacity. For example, during the Eighth Five-Year Plan, Ninth Five-Year Plan and Tenth Five-Year Plan,1 power grid investments accounted for 13.7%, 37.3% and 30% of total investment in the electricity sector, respectively. The ratio further increased from 31.1% in 2005 to 45.94% in 2008, the cumulative investment in the power grid is still significantly lower than the investments in power generation [17]. Fig. 1 gives a comparison of the ratios ofaccumulative investments in power grid and power generation in China, the US, Japan, the UK and France since 1978. In most of these countries, more than half of the electric power investment has been made on grid construction. By contrast, the ratio is less than 40% in China.According to the Articles 14 and 21 of the Chinese Renewable Energy Law, the power grid operators are responsible for thegrid connection of renewable energy projects. Subsidies are given subject to the length of the grid extension with standard rates. However, Mo [18] found that the subsidies were only sufficient to compensate for capital investment and corresponding interest but excluding operational and maintenance costs.Again, similar to grid connection, grid reinforcement requires significant amounts of capital investment. The Three Gorges power plant has provided an example of large-scale and long-distance electricity transmission in China. Similar to wind power, hydropower is usually situated in less developed areas. As a result, electricity transmission lines are necessaryt o deliver the electricity to the demand centres where the majority are located; these are the eastern coastal areas and the southern part of China. According to SGCC [19], the gridreinforcement investment of the Three Gorges power plants amounted to 34.4 billion yuan (about 5 billion US dollars). This could be a lot higher in the case of wind power due to a number of reasons. First, the total generating capacity of Three Gorges project is approximately 18.2 GW at this moment and will reach 22.4 GW when fully operating [20], whilst the total generating capacity of the massive wind farms amount to over 100 GW. Hence, more transmission capacities are absolutely necessary. Second, the Three Gorges hydropower plant is located in central China. A number of transmission paths are available, such as the 500 kV DC transmission lines to Shanghai (with a length of 1100 km), Guangzhou (located in Guangdong province, with a length of 1000 km) and Changzhou (located in Jiangsu province, with a length of 1000 km) with a transmission capacity of 3 GW each and the 500 kV AC transmission lines to central China with transmission capacity of 12 GW. By contrast, the majority of wind farm bases, which are located in the northern part of China, are far away from the load centres. For example, Jiuquan located in Gansu has a planned generation capacity of 20 GW. The distances from Jiuquan to the demand centres of the Central China grid and the Eastern China grid are 1500 km and 2500 km, respectively. For Xinjiang, the distances are even longer at 2500 km and 4000 km,respectively. As a result, longer transmission lines are required. Fig. 2 depicts the demand centres and wind farms in detail.2.2.Grid safetyThe second problem is related to grid safety. The large-scale penetration of wind electricity leads to voltage instability, flickers and voltage asymmetry which are likely to cause severe damage to the stability of the power grid [21]. For example, voltage stability is a key issue in the grid impact studies of wind power integration. During the continuous operation of wind turbines, a large amount of reactive power is absorbed, which lead to voltage stability deterioration [22]. Furthermore, the significant changes in power supply from wind might damage the power quality [23]. Hence, additional regulation capacity would be needed. However, in a power system with the majority of its power from base load provider, the requirements cannot be met easily [24]. In addition, the possible expansion of existing transmission lines would be necessary since integration of large-scale wind would cause congestion and other grid safety problems in the existing transmission system. For example, Holttinen [23] summarized the majorimpacts of wind power integration on the power grid at the temporal level (the impacts of power outputs at second, minute to year level on the power grid operation) and the spatial level (the impact on local, regional and national power grid). Besides the impacts mentioned above, the authors highlight other impacts such as distribution efficiency, voltage management and adequacy of power on the integration of wind power [23].One of the grid safety problems caused by wind power is reported by the (SERC) State Electricity Regulatory Commission [25]. In February and April of 2011, three large-scale wind power drop-off accidents in Gansu (twice) and Hebei caused power losses of 840.43 MW, 1006.223 MW and 854 MW, respectively, which accounted for 54.4%, 54.17% and 48.5% of the total wind powered outputs. The massive shutdown of wind turbines resulted in serious operational difficulties as frequency dropped to 49.854 Hz, 49.815 Hz and 49.95 Hz in the corresponding regional power grids.The Chinese Renewable Energy Law requires the power grid operators to coordinate the integration of windmills and accept all of the wind powered electricity. However, the power grid companies have been reluctant to do so due to the above mentioned problems as well as technical and economic reasons. For instance, more than one third of the wind turbines in China, amounting to 4 GW capacity, were not connected to the power grid by the end of 2008 [17]. Given that the national grid in China is exclusively controlled by the power companies – SGCC and CSG - the willingness ofthese companies to integrate wind energy into the electricity generation systems is critical.2.3.T he interconnection of provincial and regional power gridsThe interconnection of trans-regional power grids started at the end of 1980s. A (HVDC) high voltage direct current transmission line was established to link the Gezhouba2 dam with Shanghai which signifies the beginning of regional power grids interconnection. In 2001, two regional power grids, the North China Power Grid and Northeast China Power Grid were interconnected. This was followed by the interconnection of the Central China Power Grid and the North China Power Grid in 2003. In 2005, two other interconnection agreements were made between the South China Power Grid with North, Northeast and Central China Power Grid, and the Northwest China Power Grid and the Central China Power Grid. Finally, in 2009, the interconnection of Central China Power Grid and the East China Power Grid was made. In today ' s China, the Chinesepower transmission systems are composed of 330 kV and 500 kV transmission lines as the backbone and six interconnected regional power grids and one Tibet power grid [26].It seems that the interconnectivity of regional power grids would help the delivery of wind powered outputs from wind-rich regions todemand centres. However, administrative and technical barriers stillexist. First, the interconnectivity among regions is always considered as a backup to contingencies, and could not support the large-scale, long-distance electricity transmission [27]. In addition, the construction of transmission systems is far behind the expansion of wind power. The delivery of large amounts of wind power would be difficult due to limited transmission capacity. Furthermore, the quantity of inter-regional electricity transmission is fixed [27]. Additional wind power in theinter-regional transmission might have to go through complexadministrative procedures and may result in profit reductions of conventional power plants.3. Are the backup systems geographically available and technically feasible?Power system operators maintain the security of power supply by holding power reserve capacities in operation. Although terminologies used in the classification of power reserves vary among countries [28], power reserves are always used to keep the production and generation in balance under a range of circumstances, including power plant outages, uncertain variations in load and fluctuations in power generations (such as wind) [29]. As wind speed varies on all time scales (e.g. from seconds to minutes and from months to years), the integration of fluctuating wind power generation induces additional system balancing requirements on the operational timescale [29].A number of studies have examined the approaches to stabilize the electricity output from wind power plants. For example, Belanger and Gagnon [30] conducted a study on the compensation of wind power fluctuations by using hydropower in Canada. Nema et al. [31] discussed the application of wind combined solar PV power generation systems and concluded that the hybrid energy system was a viable alternative to current power supply systems in remote areas. In China, He et al. [2]investigated the choices of combined power generation systems. The combinations of wind-hydro, wind-diesel, wind-solar and wind-gas power were evaluated respectively. They found that, for instance, the wind-diesel hybrid systems were used at remote areas and isolated islands. This is because the wind-diesel hybrid systems have lower generation efficiency and higher generation costs compared to other generation systems. Currently, the wind-solar hybrid systems are not economically viable for large-scale application; thus, these systems have either been used at remote areas with limited electricity demand (e.g. Gansu Subei and Qinghai Tiansuo) or for lighting in some coastal cities [2]. Liu et al. [32] adopted the EnergyPLAN model to investigate the maximum wind power penetration level in the Chinese power system. The authors derived a conclusion that approximately 26% of national power demand could be supplied by wind power by the end of 2007. However, theauthors fail to explain the provision of power reserves at different time scales due to wind power integration.Because of the smoothing effects of dispersing wind turbines at different locations (as exemplified by Drake and Hubacek [33] for theU.K., Roques [34] for the E.U. and Kempton et al. [35] for the U.S.), the integration of wind power has a very small impact on the primary reserves which are available from seconds to minutes [36]. However, the increased reserve requirements are considerable on secondary reserves (available within 10 –15 min) which mainly consist of hydropower plants and gas turbine power plants [29]. Besides, the long-term reserves, which are used to restore secondary reserves after a major power deficit, will be in operation to keep power production and consumption in balance for a longer timescale (from several minutes to several hours). In the following subsection, we examine the availability of power plants providing secondary and long-term reserves and investigate the viability of energy storage system in China.中文中国的风力发电–梦想还是现实？胡巴切克摘要经过近几年风力发电能力的巨大增长，中国现在拥有 44.7 吉瓦的风力发电。
风力发电英文作文
风力发电英文作文英文：Wind power is a renewable energy source that has gained popularity in recent years. It involves the use of wind turbines to generate electricity, which can then be used to power homes, businesses, and even entire cities. One of the benefits of wind power is that it is clean and does not produce any harmful emissions, unlike fossil fuels.Another advantage of wind power is that it is cost-effective. While the initial investment in wind turbines can be high, the cost of producing electricity from wind power is much lower than that of traditional power sources. This is because wind is a free and abundant resource, and once the turbines are installed, the cost of producing electricity is relatively low.In addition to being a clean and cost-effective energy source, wind power also has the potential to create jobsand stimulate economic growth. The construction and maintenance of wind turbines require skilled workers, and the development of wind farms can create new opportunities for businesses and entrepreneurs.However, there are also some challenges associated with wind power. One of the biggest challenges is that wind is an intermittent energy source, meaning that it is not always available. This can make it difficult to rely solely on wind power to meet energy needs. Additionally, wind turbines can be noisy and can have negative impacts on wildlife and their habitats.Despite these challenges, wind power is still a promising energy source that has the potential to play a significant role in our transition to a more sustainable future.中文：风力发电是一种可再生能源，近年来受到了广泛的关注。
风力发电 英文作文
风力发电英文作文英文：Wind power is a type of renewable energy that has been gaining popularity in recent years. It involves harnessing the power of wind to generate electricity. I think wind power is a great alternative to traditional forms of energy like oil and coal. Not only is it clean and sustainable, but it also has the potential to be very cost-effective.One of the benefits of wind power is that it doesn't produce any greenhouse gas emissions. This means that it doesn't contribute to climate change like fossil fuels do. Additionally, wind power is renewable, meaning that itwon't run out like oil and coal will. This makes it a much more sustainable option for the future.Another advantage of wind power is that it can be very cost-effective. While the initial investment in wind turbines can be expensive, the cost of generatingelectricity from wind power is much lower than with fossil fuels. This is because the fuel (wind) is free, and there are no ongoing costs for mining or transporting fuel.Of course, there are also some challenges associated with wind power. One of the biggest is that wind power is intermittent, meaning that it can't be relied on to generate electricity all the time. This is because wind speeds can vary greatly depending on the weather. However, this can be mitigated by using a combination of different renewable energy sources, like wind and solar power.Overall, I think wind power is a great alternative to traditional forms of energy. It's clean, sustainable, and has the potential to be very cost-effective. While there are some challenges to overcome, I believe that wind power will play an important role in our transition to a more sustainable future.中文：风力发电是一种近年来越来越受欢迎的可再生能源类型。
关于风能的英文文章
关于风能的英文文章1.Wind energy is a clean and renewable source of energy derived from solar radiation and temperature differences between the surface of the Earth and the atmosphere. It is abundant in many parts of the world, particularly in open areas both on land and at sea. With technological advancements and increased demand for renewable energy sources, wind energy has become an important source of electricity.Wind energy generation converts wind energy into electricity. Wind farms typically consist of a series of large wind turbines, known as turbines or windmills. When the wind blows through these turbines, they rotate and drive generators to produce electricity.Wind energy generation has many advantages. Firstly, it is renewable, meaning it does not deplete natural resources. Secondly, wind energy generation does not emit greenhouse gases and other harmful substances, making it environmentally friendly. In addition, wind energy generation can reduce dependence on fossil fuels, thereby reducing dependence on imported energy and enhancing energy security.However, there are also some challenges and limitations to wind energy generation. Firstly, wind speed is unstable, so the power output of a wind farm is also unstable. In addition, the construction and maintenance of wind farms require significant capital investment and expertise. Furthermore, some people argue that wind energy generation may pose a threat to birds and other animals.Despite these challenges, with ongoing technological advancements and increased demand for renewable energy sources, the role of wind energy generation in global energy supply is becoming increasingly important. In the future, with the development of more efficient and reliable wind energy technologies and advanced grid technologies, the prospects for wind energy generation will become even more optimistic.风能是一种清洁、可再生的能源，它来源于太阳辐射和地球表面的温差。
外文翻译--小型风力发电机入门
外文原文Primer on Small Wind TurbinesA Little HistoryThe wind has been an important source of energy in the U.S. for a long time. The mechanical windmill was one of the two "high-technology" inventions (the other was barbed wire) of the late 1800's that allowed us to develop much of our western frontier. Over 8 million mechanical windmills have been installed in the US since the 1860's and some of these units have been in operation for more than a hundred years. Back in the 1920's and 1930's, before the REA began subsidizing rural electric coops and electric lines, farm families throughout the Midwest used 200-3,000 watt wind generators to power lights, radios, and kitchen appliances.In the late 1970's and early 1980's intense interest was once again focused on wind energy as a possible solution to the energy crisis. As homeowners and farmers looked to various electricity producing renewable energy alternatives, small wind turbines emerged as the most cost effective technology capable of reducing their utility bills. Tax credits and favorable federal regulations (PURPA) made it possible for over 4,500 small, 1-25 kW, utility-intertied wind systems to be installed at individual homes between 1976-1985. Another 1,000 systems were installed in various remote applications during the same period. Small wind turbines were installed in all fifty States. None of the small wind turbine companies, however, were owned by large companies committed to long term market development, so when the federal tax credits expired in late 1985, and oil prices dropped to $10 a barrel two months later, most of the small wind turbine industry once again disappeared. The companies that survived this "market adjustment" and are producing small wind turbines today are those whose machines were the most reliable and whose reputations were the best.The Cost FactorPhotovoltaics is an attractive technology in many ways, but cost is not one of them. Small wind turbines can be an attractive alternative, or addition, to those people needing more than 100-200 watts of power for their home, business, or remote facility. Unlike PV's, which stay at basically the same cost per watt independent of array size, wind turbines get less expensive with increasing system size. At the 50 watt size level, for example, a small wind turbine would cost about $8.00/watt compared to approximately$6.00/watt for a PV module. This is why, all things being equal, PV is lessexpensive for very small loads. As the system size gets larger, however, this "rule-of-thumb" reverses itself. At 300 watts the wind turbine costs are down to $2.50/watt ($1.50/watt in the case of the Southwest Windpower Air 403), while the PV costs are still at $6.00/watt. For a 1,500 watt wind system the cost is down to $2.00/watt and at 10,000 watts the cost of a wind generator (excluding electronics) is down to $1.50/watt. The cost of regulators and controls is essentially the same for PV and wind. Somewhat surprisingly, the cost of towers for the wind turbines is about the same as the cost of equivalent PV racks and trackers. The cost of wiring is usually higher for PV systems because of the large number of connections.For homeowners connected to the utility grid, small wind turbines are usually the best "next step" after all the conservation and efficiency improvements have been made. A typical home consumes between 800-2,000 kWh of electricity per month and a 4-10 kW wind turbine or PV system is about the right size to meet this demand. At this size wind turbines are much less expensive.ReliabilityIn the past reliability was the "Achilles Heel" of small wind turbine products. Small turbines designed in the late 1970's had a well deserved reputation for not being very reliable. Today's products, however, are technically advanced over these earlier units and they are substantially more reliable. Small turbines are now available that can operate 5 years or more, even at harsh sites, without need for maintenance or inspections and 5-year warranties are available. The reliability and cost of operation of these units is equal to that of photovoltaic systems.Wind EnergyWind energy is a form of solar energy produced by uneven heating of the Earth's surface. Wind resources are best along coastlines, on hills, and in the northern states, but usable wind resources can be found in most areas. As a power source wind energy is less predictable than solar energy, but it is also typically available for more hours in a given day. Wind resources are influenced by terrain and other factors that make it much more site specific than solar energy. In hilly terrain, for example, you and your neighbor are likely to have the exact same solar resource. But you could have a much better wind resource than your neighbor because your property is on top of the hill or it has a better exposure to the prevailing wind direction. Conversely, if your property is in a gully or on the leeward side of the hill,your wind resource could be substantially lower. In this regard, wind energy must be considered more carefully than solar energy.Wind energy follows seasonal patterns that provide the best performance in the winter months and the lowest performance in the summer months. This is just the opposite of solar energy. For this reason wind and solar systems work well together in hybrid systems. These hybrid systems provide a more consistent year-round output than either wind-only or PV-only systems. One of the most active market segments for small wind turbine manufacturers is PV-only system owners who are expanding their system with wind energy.Wind TurbinesMost wind turbines are horizontal-axis propeller type systems. Vertical-axis systems, such as the eggbeater like Darrieus and S-rotor type Savonius type systems, have proven to be more expensive. A horizontal-axis wind turbine consists of a rotor, a generator, a mainframe, and, usually, a tail. The rotor captures the kinetic energy of the wind and converts it into rotary motion to drive the generator. The rotor usually consists of two or three blades. A three blade unit can be a little more efficient and will run smoother than a two blade rotor, but they also cost more. The blades are usually made from either wood or fiberglass because these materials have the needed combination of strength and flexibility (and they don't interfere with television signals!).The generator is usually specifically designed for the wind turbine. Permanent magnet alternators are popular because they eliminate the need for field windings. A low speed direct drive generator is an important feature because systems that use gearboxes or belts have generally not been reliable. The mainframe is the structural backbone of the wind turbine and it includes the "slip-rings" that connect the rotating (as it points itself into changing wind directions) wind turbine and the fixed tower wiring. The tail aligns the rotor into the wind and can be a part of the over speed protection.A wind turbine is a deceptively difficult product to develop and many of the early units were not very reliable. A PV module is inherently reliable because it has no moving parts and, in general, one PV module is as reliable as the next. A wind turbine, on the other hand, must have moving parts and the reliability of a specific machine is determined by the level of skill used in its engineering and design. In other words, there can be a big difference in reliability, ruggedness, and life expectancy from one brandto the next. This is a lesson that often seems to escape dealers and customers who are used to working with solar modules.TowersA wind turbine must have a clear shot at the wind to perform efficiently. Turbulence, which both reduces performance and "works" the turbine harder than smooth air, is highest close to the ground and diminishes with height. Also, wind speed increases with height above the ground. As a general rule of thumb, you should install a wind turbine on a tower such that it is at least 30 ft above any obstacles within 300 ft. Smaller turbines typically go on shorter towers than larger turbines. A 250 watt turbine is often, for example, installed on a 30-50 ft tower, while a 10 kW turbine will usually need a tower of 80-120 ft. We do not recommend mounting wind turbines to small buildings that people live in because of the inherent problems of turbulence, noise, and vibration.The least expensive tower type is the guyed-lattice tower, such as those commonly used for ham radio antennas. Smaller guyed towers are sometimes constructed with tubular sections or pipe. Self-supporting towers, either lattice or tubular in construction, take up less room and are more attractive but they are also more expensive. Telephone poles can be used for smaller wind turbines. Towers, particularly guyed towers, can be hinged at their base and suitably equipped to allow them to be tilted up or down using a winch or vehicle. This allows all work to be done at ground level. Some towers and turbines can be easily erected by the purchaser, while others are best left to trained professionals. Anti-fall devices, consisting of a wire with a latching runner, are available and are highly recommended for any tower that will be climbed. Aluminum towers should be avoided because they are prone to developing cracks. Towers are usually offered by wind turbine manufacturers and purchasing one from them is the best way to ensure proper compatibility.Remote Systems EquipmentThe balance-of-systems equipment used with a small wind turbine in a remote application is essentially the same as used with a PV system. Most wind turbines designed for battery charging come with a regulator to prevent overcharge. The regulator is specifically designed to work with that particular turbine. PV regulators are generally not suitable for use with a small wind turbine because they are not designed to handle the voltage and current variations found with turbines. The output from the regulator istypically tied into a DC source center, which also serves as the connection point for other DC sources, loads and the batteries. For a hybrid system the PV and wind systems are connected to the DC source center through separate regulators, but no special controls are generally required. For small wind turbines a general rule-of-thumb is that the AH capacity of the battery bank should be at least six times the maximum renewables charging current, including any PV elements. The wind industry has had good experience using battery banks that are smaller than those typically recommended for PV applications.Being Your Own Utility CompanyThe federal PURPA regulations passed in 1978 allow you to interconnect a suitable renewable energy powered generator to your house or business to reduce your consumption of utility supplied electricity. This same law requires utilities to purchase any excess electricity production at a price (avoided cost) usually below the retail cost of electricity. In about a half-dozen states with "net energy billing options" small systems are allowed to run the meter backwards, so they get the full retail rate for excess production. Because of the high overhead costs to the utilities for keeping a few special hand-processed customer accounts, net energy billing is actually less expensive for them. These systems do not use batteries. The output of the wind turbine is made compatible with utility power using either a line-commutated inverter or an induction generator. The output is then connected to the household breaker panel on a dedicated breaker, just like a large appliance. When the wind turbine is not operating, or it is not putting out as much electricity as the house needs, the additional electricity needed is supplied by the utility. Likewise, if the turbine puts out more power than the house needs, the excess is instantaneously "sold" to the utility. In effect, the utility acts as a very big battery bank and the utility "sees" the wind turbine as a negative load. After over 200 million hours of interconnected operation we now know that small utility-interconnected wind turbines are safe, do not interfere with either utility or customer equipment, and do not need any special safety equipment to operate successfully.Hundreds of homeowners around the country who installed 4-12 kW wind turbines during the go-go tax credit days in the early 1980's now have everything paid for and enjoy monthly electrical bills of $8-30, while their neighbors have bills in the range of $100-200 per month. The problem, of course, is that these tax credits are long gone and without them most homeowners will find the cost of a suitable wind generator prohibitively expensive. A 10 kW turbine (the most common size for homes), for example,will typically cost $28,000-35,000 installed. For those paying 12cents/kilowatt-hour or more for electricity in an area with an average wind speed of 10 mph or more (DOE Class 2), and with an acre or more of property (the turbines are big), a residential wind turbine is certainly worth considering. Payback periods will generally fall in the range of 8-16 years and some wind turbines are designed to last thirty years or more.PerformanceThe rated power for a wind turbine is not a good basis for comparing one product to the next. This is because manufacturers are free to pick the wind speed at which they rate their turbines. If the rated wind speeds are not the same then comparing the two products is very misleading. Fortunately, the American Wind Energy Association has adopted a standard method of rating energy production performance. Manufacturers who follow the AWEA standard will give information on the Annual Energy Output (AEO) at various annual average wind speeds. These AEO figures are like the EPA Estimated Gas Mileage for your car, they allow you to compare products fairly, but they don't tell you just what your actual performance will be ("Your Performance May Vary").Wind resource maps for the US have been compiled by the Department of Energy. These maps show the resource by "Power Classes" that mean the average wind speed will probably be within a certain band. The higher the Power Class the better the resource. We say probably because of the terrain effects mentioned earlier. On open terrain the DOE maps are quite good, but in hilly or mountainous terrain they must be used with great caution. The wind resource is defined for a standard wind sensor height of 33 ft (10 m), so you must correct the average wind speed for wind tower heights above this height before using the AEO information supplied by the manufacturer. Wind turbine performance is also usually derated for altitude, just like an airplane, and for turbulence. Wind turbine manufacturers can usually providecomputer-aided performance predictions for their turbines at virtually any site.As a rule of thumb wind energy should be considered if your average wind speed is above 8 mph (most, but not all, Class 1 and all other Classes) for a remote application and 10 mph (Class 2 or better) for a utility-interited application. If you live in an area that is not too hilly then the DOE wind resource map can be used to fairly accurately calculate the expected performance of a wind turbine at your site. In complex terrain a judgment on the site's exposure must be made to adjust the average wind speed used for this calculation. In most situations it is not necessary to monitor thewind speed with a recording anemometer prior to installing a small wind turbine. But in some situations it is worth spending $300-1,000 and waiting a year to perform a wind survey. Manufacturers and equipment dealers can help sort out these questions.How Wind Turbines are UsedInstalling a wind turbine is a bit more involved than installing solar panels, but they are still relatively easy to incorporate into your alternative energy system. The turbine needs to be mounted in an area free from obstructions to wind flow (nearby buildings, trees, etc.).Some smaller turbines can be mounted to the rooftop of your house, but vibrations from the turbine may be transferred to the frame of the building. Rooftop turbine mounts often come with rubber vibration dampers to minimize this problem. As a general rule however, the higher in the air you can get your wind turbine the more effective it will be, so independent, guyed towers are the recommended mounting system. The wide variety of available tower heights and styles makes it much more likely you will find a mounting kit to suit your needs.When installing the controls and wiring of a wind generator, it is important to understand two fundamental differences between wind turbines and solar panels:Current Rectifiers: Solar panels produce direct current (DC) electricity required by power storage batteries, and can be connected directly to the battery bank without causing harm. Wind generators do not produce DC electricity, so a device called a "rectifier" is used to convert the turbine's output current to DC.Some turbines have a rectifier built in. In most cases though, the rectifier is supplied as a separate component that must be installed between the wind turbine and the battery. Often, the rectifier is combined with a charge controller into one complete wind turbine control unit.Load Diversion:Solar panels are "passive" electricity producers. Even though the sun is shining, they only produce electricity when a charge is needed by the battery. Wind generators are "active" electricity producers. If the wind is blowing, they will produce current whether the battery bank needs the charge or not. In order to prevent damage to the wind turbine, all of the electricity it produces must be "used" in.When the system batteries need charging current, they provide an electrical load to use the wind turbine's electricity. If the batteries are fully charged, the turbine's output must be "diverted" to another electrical load.A load diverting charge controller regulates wind generator output so your batteries receive charging current when they need it, and any excess electricity generated by the wind turbine is diverted to an alternate load when the batteries are fully charged.Some wind turbines have charge control features built-in, diverting their own excess current and allowing it to dissipate as heat through the wind turbine housing. In most turbine systems however, the charge controller is an external unit.中文译文小型风力发电机入门历史在美国相当长的时间里，风能一直是一个重要的能量来源。
风力发电电力系统中英文对照外文翻译文献
中英文对照外文翻译(文档含英文原文和中文翻译)附件1：翻译译文风力发电对电力系统的影响摘要风力发电依赖于气象条件，并逐渐以大型风电场的形式并入电网，给电网带来各种影响。
电网并未专门设计用来接入风电，因此如果要保持现有的电力供应标准，不可避免地需要进行一些相应的调整。
讨论了在风电场并网时遇到的各种问题。
由于风力发电具有大容量、动态和随机的特性，它给电力系统的有功/无功潮流、电压、系统稳定性、电能质量、短路容量、频率和保护等方面带来影响。
针对这些问题提出了相应的解决建议和措施，以及更好利用风力发电。
关键词：风力发电；电力系统；影响；风电场1.引言人们普遍接受，可再生能源发电是未来电力的供应。
由于电力需求快速增长，对以化石燃料为基础的发电是不可持续的。
正相反，风力发电作为一种有前途的可再生能源受到了很多关注。
当由于工业的发展和在世界大部分地区的经济增长而发电的消费需求一直稳步增长时，它有减少排放和降低不可替代的燃料储备消耗的潜力。
当大型风电场（几百兆瓦）是一个主流时，风力发电越来越更受欢迎。
2006年间，世界风能装机容量从2005年的59091兆瓦达到74223兆瓦。
在2006年极大的生长表明，决策者开始重视的风能发展能够带来的好处。
由于到2020年12%的供电来于1250GW的安装风电装机，将节约累积10771000000吨二氧化碳[1]。
大型风电场的电力系统具有很高的容量，动态随机性能，这将会挑战系统的安全性和可靠性。
而提供电力系统清洁能源的同时，风农场也会带来一些对电力系统不利的因素。
风力发电的扩展和风电在电力系统的比重增加，影响将很可能成为风力集成的技术性壁垒。
因此，应该探讨其影响和提出克服这些问题的对策。
2.风力发电发展现状从全球风能委员会（GWEC）的报告中，拥有最高装机容量总数的国家是德国（20621兆瓦），西班牙（11615兆瓦），美国（11603兆瓦），印度（6270兆瓦）和丹麦（3136兆瓦）。
有关风能发电的英语作文
有关风能发电的英语作文英文回答：Wind energy is a rapidly growing source of renewable energy that has the potential to provide a significant portion of the world's electricity needs. It is a clean, sustainable, and cost-effective way to generate electricity, and it can help to reduce our dependence on fossil fuels.Wind turbines convert the kinetic energy of the windinto electrical energy. The turbines are mounted on towers, and the blades rotate when the wind blows. The rotation of the blades turns a generator, which produces electricity.Wind energy is a variable resource, which means that it is not always available. However, the wind can be predicted with reasonable accuracy, and wind turbines can be sited in areas where the wind blows frequently.Wind energy is a relatively new technology, but it israpidly becoming more efficient and cost-effective. The cost of wind energy has fallen significantly in recent years, and it is now competitive with other forms of renewable energy, such as solar energy.Wind energy has a number of advantages over other forms of renewable energy. It is a clean source of energy, and it does not produce any greenhouse gases. Wind turbines are also relatively quiet, and they can be sited in areas where they will not have a negative impact on the environment.Wind energy is a promising source of renewable energy that has the potential to make a significant contribution to the world's energy needs. It is a clean, sustainable, and cost-effective way to generate electricity, and it can help to reduce our dependence on fossil fuels.中文回答：风能是一种增长迅速的可再生能源，它有可能为世界提供大量的电力需求。
有关风力发电的外文文献翻译
大型风力发电对电力系统稳定性的影响Ch. Eping, J. Stenzel电力系统研究所TU DarmstadtLandgraf-Georg-Stra¼e 464283 Darmstadt/德国e-mail：*********************************.de********************************.deM. PÄoller, HMÄullerDIgSILENT GmbHHeinrich-Hertz-Stra¼e 972810 Gomaringen /德国e-mail:*******************************************摘要近年来，风力发电量不断增加，对电力系统的安全性和系统运行的影响也不断增加。
因此，最近在不同的国家已经进行一些风电影响的研究了。
这些研究的结果通常会涉及到不同的风力发电方面，如波动性，分布式风电场发电机技术，发电机控制等和后备并网预测，其他储备的要求等等。
本文重点对影响暂态稳定问题的几个方面进行分析，像发电机技术，连接点，分布式发电等对暂态稳定方面的影响分别进行了透彻分析。
1引言风力发电的重要性日益增加，特别在许多欧洲国家、美国、加拿大、和澳大利亚。
这要求风力发电对电力系统稳定性的影响进行详细分析。
因此，最近已经进行了所需的一些网络加固，资金准备要求，目前正在开展风力发电对电力系统稳定性影响的研究（如[2]）。
这些研究处理与风力发电有关的几个不同的方面，如波动性风电，当地风力资源，各种发电机技术和发电机控制。
结果大致是，不同的风力发电方面的共同并网和并网后备预测，额外的储备要求，对电力系统稳定性的影响等，但是很难的解决遇到的问题和所需的系统升级，因为要同时进行大量各种方面的研究。
本文的目的是分析和理解，而不是实际的数字和计算。
这次调查的是暂态稳定现象，特别是暂态稳定长距离输电的限制。
风力发电的英文作文
风力发电的英文作文Wind power is a renewable energy source that harnesses the power of the wind to generate electricity. It is a clean and sustainable alternative to traditional fossil fuels.Wind turbines are tall structures with large bladesthat spin when the wind blows. The spinning motion generates electricity through a generator, which is then transmitted to homes and businesses through power lines.One of the advantages of wind power is that it produces no greenhouse gas emissions or air pollutants. This helps reduce the negative impact of climate change and improveair quality.Wind power can be generated both onshore and offshore. Onshore wind farms are located on land, while offshore wind farms are located in bodies of water such as oceans and lakes.Although wind power has many benefits, it also has some challenges. One challenge is that wind is an intermittent energy source, meaning it is not always available. This can make it difficult to rely solely on wind power for electricity generation.Despite its challenges, wind power has seen significant growth in recent years as countries around the world work to reduce their reliance on fossil fuels and transition to clean energy sources. With continued advancements in technology, wind power has the potential to play a major role in the future of energy production.。
风力发电中英文对照外文翻译文献
中英文资料对照外文翻译水平轴风力发电机性能过渡，湍流和偏航的影响摘要最近出示的是改善的功能改善的混合动力车的的水平轴风力涡轮机（HAWT）配置Navier-Stokes势流建模方法。
研究的重点在三个问题上：湍流模型和转换模型，预测转子规定性能唤醒状态以及非轴向流（偏航）发电的影响，比较转子在国家可再生能源实验室（NREL）的测试与测量数据.简介水平轴风力涡轮机空气动力学的计算研究工作是在佐治亚理工学院进行。
本研究着重于了解影响风力涡轮机在非轴向和非均匀流入的流动机制的性能，也解决了高效的计算技术的发展，以补充现有的联合叶片元素动量理论方法。
这项工作是一个扩展的3-D的混合Navier-Stokes/potential流动求解，并已在佐治亚理工学院的水平轴风力发电机（HAWT）进行改善。
在这种方法中的三维非定常可压缩Navier-Stokes方程的解决只能在周围的转子叶片上的贴体网格这片一个很小的区域，。
远离叶片的和潜在的流动方程需要从叶片脱落的涡模拟涡细丝涡留下的Navier-Stokes地区的求解。
这些细丝自由对流的地方流动。
由于复杂的Navier-Stokes方程的计算只在附近的风力涡轮机叶片的地区，因此跟踪的涡利用拉格朗日方法，这是更有效的Navier-Stokes方程的方法级。
基本的Navier-Stokes方程混合势流的方法和其应用程序HAWT下轴流条件的记录在AIAA-99-0042（徐和Sankar，1999年）.本研究范围本文介绍了近期的流动求解的增强功能和应用程序配置的兴趣。
增强集中在以下三个方面：过渡和湍流模型，物理一致唤醒建模，建模的偏航效果。
下文简要讨论这三个领域。
过渡和湍流的建模问题：研究两种湍流模型和两个过渡模型的预测性能影响的进行评估。
一个显示Spalart-Allmaras湍流方程湍流模型（书珥等，1998），另一个对基线鲍德温 - 洛马克斯零方程湍流模型进行了研究。
风力发电论文摘要英文翻译
风力发电论文摘要英文翻译摘要风力发电是清洁的、无污染的可再生能源，它的优势已被人们所认识。
但是现阶段风力发电成本与常规能源相比仍不具有优势，特别是在我国，风力发电成本还难与同常规能源相竞争，这制约了我国风电事业的发展。
因此全面地研究我国风力发电成本、研究影响风力发电成本的因素、找到降低风力发电成本的途径，对促进我国风电事业的发展、改进我国能源结构、治理我国的环境污染具有重要的现实意义。
为此社会总成本实际成本风电场关键字:风力发电ABSTRACTThis paper introduces wind Power generation cost in china Wind Power is a kind of cleaner and no pollution and regenerate power, Its benefits has been known by most people.But it has been yet inferior to routine power in cost, especially in our country. So studying the cost of the wind power generation and studying the factors of affecting wind power generation costs and finding the ways of decreasing the wind power generation costs in our country have very important realistic meanings and it can promote the cause of the wind power generation and improvethe energy constitutes and administer circumstance pollution in our country.hence,this paper is accomplished to develop the study of the wind power generation cost:First ,the history and the present of wind power generation are introduced: Second ,the social cost of wind power generation are studied by means of comprehensive analyses.draw a conclusion;the social cost of wind power generation is lower;Third ,the real cost of wind power generation are studied by model of wind distribution and generation amount and calculating the cost of wind power generation;the factors affecting wind power generation cost are studied by sensitivities with a real example and draw a conclusion:average wind rate is most influence to wind power generation cost and the ways of reducing wind power generation cost are discussed. Fourth ,the trend of wind power generation cost is analysised and draw a conclusion;wind power generation cost is dropping.Key word: wind power generation the social cost the real cost wind powergeneration farm目录1 概述 (1)1.1风力发电的研究现状 (1)1.2我国风力发电的发展状况 (3)1.3发展风力发电的必要性和意义 ......................................... 4 2中国风力发电社会总成本的研究 (6)2.1研究方法的选择 (6)2.2原理及步骤 (6)2.2.1具体步骤 .....................................................62.2.2 进行层次总排序 ...............................................8 3层次分析综合评价法的应用 (9)3.1建立层次结构模型 (9)3.2构造判断矩阵 (9)3.3 进行层次单排序极其一致性检验 (11)3.4进行层次总排序 (13)3.5层次总排序一致性检验 (14)3.6世界各国促进风力发电发展的激励政策 (14)3.7小结 .............................................................. 16 4中国风力发电的成本走势分析 (16)4.1风机国产化的形式对成本走势的影响 (16)4.2.国家政策 (16)4.3目前我国风力发电成本较高原因分析 (17)4.3.1目前我国风力发电成本较高原因 ................................174.3.2解决的方法 ..................................................194.3.3风力发电在我国发展的美好前景 ................................19 谢辞 ..................................................................20 参考文献 ...............................................................21大连交通大学信息工程学院2011届本科生毕业设计(论文)1 概述1.1风力发电的研究现状风力发电于1890年起源于丹麦，之后经过几个重要的发展阶段。
有关风能发电的英语作文
有关风能发电的英语作文英文回答：Wind energy is a form of renewable energy that harnesses the power of the wind to generate electricity. It is a clean and sustainable source of energy that does not produce any emissions or waste. Wind turbines, which are used to convert the kinetic energy of the wind into electrical energy, are typically installed in windy areas, such as coastal regions, mountain passes, and open fields.One of the main advantages of wind energy is its cost-effectiveness. Wind turbines have become increasingly efficient and affordable over the years, making wind energy one of the most competitive renewable energy sources. Additionally, wind energy is a reliable source of energy, as wind is a relatively predictable resource.However, wind energy also has some disadvantages. One of the main challenges is that wind power is intermittent,meaning that it is not always available when needed. This can be overcome by integrating wind energy with other renewable energy sources, such as solar energy, which is available during the day when wind power is typically less available.Another challenge with wind energy is that wind turbines can have a negative impact on wildlife,particularly birds and bats. However, there are a number of measures that can be taken to mitigate this impact, such as siting wind turbines in areas where there is less wildlife activity and using bird deterrents.Overall, wind energy is a promising renewable energy source that has the potential to make a significant contribution to meeting our global energy needs. It is a clean, sustainable, and cost-effective source of energythat can help us to reduce our reliance on fossil fuels.中文回答：风能是一种可再生能源，利用风力发电。
风力发电机用专业英语中英文对照
风力机 wind turbine风电场 wind power station wind farm风力发电机组 wind turbine generator system WTGS 水平轴风力机 horizontal axis wind turbine垂直轴风力机 vertical axis wind turbine轮毂（风力机） hub (for wind turbine)机舱 nacelle支撑结构 support structure for wind turbine关机 shutdown for wind turbine正常关机 normal shutdown for wind turbine紧急关机 emergency shutdown for wind turbine空转 idling锁定 blocking停机 parking静止 standstill制动器 brake停机制动 parking brake风轮转速 rotor speed控制系统 control system保护系统 protection system偏航 yawing设计和安全参数 design situation设计工况 design situation载荷状况 load case外部条件 external conditions设计极限 design limits极限状态 limit state使用极限状态 serviceability limit states极限限制状态 ultimate limit state最大极限状态 ultimate limit state安全寿命 safe life严重故障 catastrophic failure潜伏故障 latent fault dormant failure风特性wind characteristic风速 wind speed风矢量 wind velocity旋转采样风矢量 rotationally sampled wind velocity 额定风速 rated wind speed切入风速 cut-in speed切出风速 cut-out speed年平均annual average年平均风速 annual average wind speed平均风速mean wind speed。
毕业论文风力发电机技术参考文献外文
Wind Power Generation TechnologyWind 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 world's attention, and the fastest.Wind energy technology is a high-tech; it relates 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 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: 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 power to distinguish between small and medium treated separately. In addition, to meet different market needs, extending from 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 power 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 resource-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 large-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 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 overlook forward 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 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. The technology of small wind power:The 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 small 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 used in distributed independent power supply. These years as Chinese exports of small and medium wind steadily. Internationally, China's small and medium sized wind power technology and wind and solar technology have leapt to international leadership.Small wind power technology is mature and relatively 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 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 country's most technical advantages and competitiveness of small and medium wind power has always been forgotten by the government 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 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 generation, pitch moment, multiple protection, and a series of technical attention by the international market and international clientsunanimously approved, has a leading position. Moreover, the small and medium Wind power technology is ultimately distributed independent power supply to meet end-market, 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 Solar 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 technology 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 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 are 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 still 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 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 fourthRevolution.Second，Wind power 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 aunit 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 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 plasma from regulationWind turbines impeller, will capture the wind by converting wind effects on the mechanical wheeltorque.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 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 function 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 speed 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, can 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 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 typestall fan vibration power pulse are small, and accommodation type from wind 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.Third, the development of wind energy technology requires constant innovation:At present, China's 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 take 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 future, can not 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 supporting, 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 wind 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 new industry can be brought aboutnumerous development and transformation of traditional industries, but the application of wind energy technology in various fields has become the industry's benchmark. World revolution will be caused by wind energy technology from the New Energy and Industrial revolution.风力发电技术风能是非常重要并储量巨大的能源，它安全、清洁、充裕，能提供源源不绝，稳定的能源。
毕业论文风力发电机技能参考文献外文
毕业论文风力发电机技能参考文献外文unanimously approved, has a leading position. Moreover, the small and medium Wind power technology is ultimately distributed independent power supply to meet end-market, 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 Solar 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 technology 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 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 are 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 powerconversion rate is only 1/5-1/6 of the same 60% -80%, only the low price Worse still 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 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 fourthRevolution.Second，Wind power 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。
风力发电机毕业论文英文文献翻译
附录一英文文献Wind Energy Introduction1.1 Historical DevelopmentWindmills have been used for at least 3000 years, mainly for grinding grain or pumping water, while in sailing ships the wind has been an essential source of power for even longer. From as early as the thirteenth century, horizontal-axis windmills were an integral part of the rural economy and only fell into disuse with the advent of cheap fossil-fuelled engines and then the spread of rural electrification.The use of windmills (or wind turbines) to generate electricity can be traced back to the late nineteenth century with the 12 kW DC windmill generator constructed by Brush in the USA and the research undertaken by LaCour in Denmark. However, for much of the twentieth century there was little interest in using wind energy other than for battery charging for remote dwellings and these low-power systems were quickly replaced once access to the electricity grid became available. One notable exception was the 1250 kW Smith–Putnam wind turbine constructed in the USA in 1941. This remarkable machine had a steel rotor 53 m in diameter, full-span pitch control and flapping blades to reduce loads. Although a blade spar failed catastrophically in 1945, it remained the largest wind turbine constructed for some 40 years (Putnam, 1948).Golding (1955) and Shepherd and Divone in Spera (1994) provide a fascinating history of early wind turbine development. They record the 100 kW 30 m diameter Balaclava wind turbine in the then USSR in 1931 and the Andrea Enfield 100 kW 24 m diameter pneumatic design constructed in the UK in the early 1950s. In this turbine hollow blades, open at the tip, were used to draw air up through the tower where another turbine drove the generator. In Denmark the 200 kW 24 m diameter Gedser machine was built in 1956 while Electricite´de France tested a 1.1 MW 35 m diameter turbine in 1963. In Germany, Professor Hutter constructed a number of innovative, lightweight turbines in the 1950s and 1960s. In spite of these technical advances and the enthusiasm, among others, of Golding at the Electrical Research Association in the UK there was little sustained interest in wind generation until the price of oil rose dramatically in 1973.The sudden increase in the price of oil stimulated a number of substantial Government-funded programmes of research, development and demonstration. In the USA this led to the construction of a series of prototype turbines starting with the 38 m diameter 100 kW Mod-0 in 1975 and culminating in the 97.5 m diameter 2.5 MW Mod-5B in 1987. Similar programmes were pursued in the UK, Germany and Sweden. There was considerable uncertainty as to which architecture might prove most cost-effective and several innovative concepts were investigated at full scale. In Canada, a 4 MW vertical-axis Darrieus wind turbine was constructed and this concept was also investigated in the 34 m diameter Sandia Vertical Axis Test Facility in the USA. In the UK, an alternative vertical-axis design using straight blades to give an ‘H’ type rotor was proposed by Dr Peter Musgrove and a 500 kW prototypeconstructed. In 1981 an innovative horizontal-axis 3 MW wind turbine was built and tested in the USA. This used hydraulic transmission and, as an alternative to a yaw drive, the entire structure was orientated into the wind. The best choice for the number of blades remained unclear for some while and large turbines were constructed with one, two or three blades.Much important scientific and engineering information was gained from these Government-funded research programmes and the prototypes generally worked as designed. However, it has to be recognized that the problems of operating very large Figure 1.1 1.5 MW, 64 m diameter Wind Turbine (Reproduced by permission of NEG MICON)wind turbines, unmanned and in difficult wind climates were often under-estimated and the reliability of the prototypes was not good. At the same time as the multi-megawatt prototypes were being constructed private companies, often with considerable state support, were constructing much smaller, often simpler,turbines for commercial sale. In particular the financial support mechanisms in California in the mid-1980s resulted in the installation of a very large number of quite small(<100 kW) wind turbines. A number of these designs also suffered from various problems but,being smaller, they were in general easier to repair and modify. The so-called 'Danish' wind turbine concept emerged of a three-bladed,stall-regulated rotor and a fixed-speed, induction machine drive train. This decep-tively simple architecture has proved to be remarkably successful and has now been implemented on turbines as large as 60 m in diameter and at ratings of 1.5 MW. The machines of Figures 1.1 and 1.2 are examples of this design. However, as the sizes of commercially available turbines now approach that of the large prototypes of the 1980s it is interesting to see that the concepts investigated then of variable-speed operation, full-span control of the blades, and advanced materials are being used increasingly by designers. Figure 1.3 shows a wind farm of direct-drive, variable-speed wind turbines. In this design, the synchronous generator is coupled directly to the aerodynamic rotor so eliminating the requirement for a gearbox. Figure 1.4 shows a more conventional, variable-speed wind turbine that uses a gearbox, while a small wind farm of pitch-regulated wind turbines, where full-span control of the blades is used to regulate power, is shown in Figure 1.5.Figure 1.2 750 kW, 48 m diameter Wind Turbine, Denmark (Reproduced by permission of NEG MICON)Figure 1.3 Wind Farm of Variable-Speed Wind Turbines in Complex Terrain (Reproduced by permission of Wind Prospect Ltd)Figure 1.4 1 MW Wind Turbine in Northern Ireland (Reproduced by permission of Renew-able Energy Systems Ltd)The stimulus for the development of wind energy in 1973 was the price of oil and concern over limited fossil-fuel resources. Now, of course, the main driver for use of wind turbines to generate electrical power is the very low C emissions (over the entire life cycle of manufacture, installation, operation and de-commissioning)Figure 1.5 Wind Farm of Six Pitch-regulated Wind Turbines in Flat Terrain (Reproduced by permission of Wind Prospect Ltd)and the potential of wind energy to help limit climate change. In 1997 the Commis-sion of the European Union published its White Paper (CEU, 1997) calling for 12 percent of the gross energy demand of the European Union to be contributed from renewables by 2010. Wind energy was identified as having a key role to play in the supply of renewable energy with an increase in installed wind turbine capacity from 2.5 GW in 1995 to 40 GW by 2010. This target is likely to be achievable since at the time of writing, January 2001, there was some 12 GW of installed wind-turbine capacity in Europe, 2.5 GW of which was constructed in 2000 compared with only 300 MW in 1993. The average annual growth rate of the installation of wind turbines in Europe from 1993-9 was approximately 40 percent (Zervos, 2000). The distribution of wind-turbine capacity is interesting with, in 2000, Germany account- ing for some 45 percent of the European total, and Denmark and Spain each having approximately18 percent. There is some 2.5 GW of capacity installed in the USA of which 65 percent is in California although with increasing interest in Texas and some states of the midwest. Many of the California wind farms were originallyconstructed in the 1980s and are now being re-equipped with larger modern wind turbines.Table 1.1 shows the installed wind-power capacity worldwide in January 2001 although it is obvious that with such a rapid growth in some countries data of this kind become out of date very quickly.The reasons development of wind energy in some countries is flourishing while in others it is not fulfilling the potential that might be anticipated from a simple consideration of the wind resource, are complex. Important factors include the financial-support mechanisms for wind-generated electricity, the process by which the local planning authorities give permission for the construction of wind farms,and the perception of the general population particularly with respect to visual impact. In order to overcome the concerns of the rural population over the environ-mental impact of wind farms there is now increasing interest in the development of sites offshore.1.2 Modern Wind TurbinesThe power output, P, from a wind turbine is liven by the well-known expression:P=where ρ is the density of air (1.225 kg/), is the power coefficient, A is the rotor swept area, and U is the wind speed.The density of air is rather low, 800 times less than that of water which powershydro plant, and this leads directly to the large size of a wind turbine. Depending on the design wind speed chosen, a 1.5 MW wind turbine may have a rotor that is more than 60 m in diameter. The power coefficient describes that fraction of the power in the wind that may be converted by the turbine into mechanical work. It has a theoretical maximum value of 0.593 (the Betz limit) and rather lower peak values are achieved in practice (see Chapter 3). The power coefficient of a rotor varies with the tip speed ratio (the ratio of rotor tip speed to free wind speed) and is only a maximum for a unique tip speed ratio. Incremental improvements in the power coefficient are continually being sought by detailed design changes of the rotor and, by operating at variable speed, it is possible to maintain the maximum power coefficient over a range of wind speeds. However, these measures will give only a modest increase in the power output. Major increases in the output power can only be achieved by increasing the swept area of the rotor or by locating the wind turbines on sites with higher wind speeds.Hence over the last 10 years there has been a continuous increase in the rotor diameter of commercially available wind turbines from around 30 m to more than 60 m. A doubling of the rotor diameter leads to a four-times increase in power output. The influence of the wind speed is, of course, more pronounced with a doubling of wind speed leading to an eight-fold increase in power. Thus there have been considerable efforts to ensure that wind farms are developed in areas of the highest wind speeds and the turbines optimally located within wind farms. In certain countries very high towers are being used (more than 60-80 m) to take advantage of the increase of wind speed with height.In the past a number of studies were undertaken to determine the 'optimum size of a wind turbine by balancing the complete costs of manufacture, installation and operation of various sizes of wind turbines against the revenue generated (Mollyet al. 1993). The results indicated a minimum cost of energy would be obtained with wind turbine diameters in the range of 35-60 m, depending on the assumptions made. However, these estimates would now appear to be rather low and there is no obvious point at which rotor diameters, and hence output power, will be limited particularly for offshore wind turbines.All modern electricity-generating wind turbines use the lift force derived from the blades to drive the rotor. A high rotational speed of the rotor is desirable in order to reduce the gearbox ratio required and this leads to low solidity rotors (the ratio of blade area/rotor swept area). The low solidity rotor acts as an effective energy concentrator and as a result the energy recovery period of a wind turbine, on a good site, is less than 1 year, i.e., the energy used to manufacture and install the wind turbine is recovered within its first year of operation (Musgrove in Freris, 1990).附录二英文翻译风能介绍1.1发展历史风车的使用至少已有三千年，主要用于磨粒或泵站水，而在帆船风已成为不可缺少的电力来源甚至更长的一段时间。
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风力发电外文翻译中英文英文Wind power in China – Dream or reality?HubacekAbstractAfter tremendous growth of wind power generation capacity in recent years, China now has 44.7 GW of wind-derived power. Despite the recent growth rates and promises of a bright future, two important issues - the capability of the grid infrastructure and the availability of backup systems - must be critically discussed and tackled in the medium term.The study shows that only a relatively small share of investment goes towards improving and extending the electricity infrastructure which is a precondition for transmitting clean wind energy to the end users. In addition, the backup systems are either geographically too remote from the potential wind power sites or currently financially infeasible. Finally, the introduction of wind power to the coal-dominated energy production system is not problem-free. Frequent ramp ups and downs of coal-fired plants lead to lower energy efficiency and higher emissions, which are likely to negate some of the emission savings from wind power.The current power system is heavily reliant on independently acting but state-owned energy companies optimizing their part of the system, and this is partly incompatible with building a robust system supportingrenewable energy technologies. Hence, strategic, top-down co-ordination and incentives to improve the overall electricity infrastructure is recommended.Keywords: Wind power, China, Power grids, Back-up systems1. IntroductionChina’s wind energy industry has exper ienced a rapid growth over the last decade. Since the promulgation of the first Renewable Energy Law in 2006, the cumulative installed capacity of wind energy amounted to 44.7 GW by the end of 2010 [1]. The newly installed capacity in 2010 reached 18.9 GW which accounted for about 49.5% of new windmills globally. The wind energy potential in China is considerable, though with differing estimates from different sources. According to He et al. [2], the exploitable wind energy potential is 600–1000 GW onshore and 100–200 GW offshore. Without considering the limitations of wind energy such as variable power outputs and seasonal variations, McElroy et al. [3] concluded that if the Chinese government commits to an aggressive low carbon energy future, wind energy is capable of generating 6.96 million GWh of electricity by 2030, which is sufficient to satisfy China’s electricity demand in 2030.The existing literature of wind energy development in China focuses on several discussion themes. The majority of the studies emphasize the importance of government policy on the promotion of wind energyindustry in China [4], [5], [6], [7]. For instance, Lema and Ruby [8] compared the growth of wind generation capacity between 1986 and 2006, and addressed the importance of a coordinated government policy and corresponding incentives. Several studies assessed other issues such as the current status of wind energy development in China [9]; the potential of wind power [10]; the significance of wind turbine manufacturing [11]; wind resource assessment [5]; the application of small-scale wind power in rural areas [12]; clean development mechanism in the promotion of wind energy in China [4], social, economic and technical performance of wind turbines [13] etc.There are few studies which assess the challenge of grid infrastructure in the integration of wind power. For instance, Wang [14] studied grid investment, grid security, long-distance transmission and the difficulties of wind power integration at present. Liao et al. [15] criticised the inadequacy of transmission lines in the wind energy development. However, we believe that there is a need to further investigate these issues since they are critical to the development of wind power in China. Furthermore, wind power is not a stand-alone energy source; it needs to be complemented by other energy sources when wind does not blow. Although the viability and feasibility of the combination of wind power with other power generation technologies have been discussed widely in other countries, none of the papers reviewed thesituation in the Chinese context. In this paper, we discuss and clarify two major issues in light of the Chinese wind energy distribution process: 1) the capability of the grid infrastructure to absorb and transmit large amounts of wind powered electricity, especially when these wind farms are built in remote areas; 2) the choices and viability of the backup systems to cope with the fluctuations of wind electricity output.2. Is the existing power grid infrastructure sufficient?Wind power has to be generated at specific locations with sufficient wind speed and other favourable conditions. In China, most of the wind energy potential is located in remote areas with sparse populations and less developed economies. It means that less wind powered electricity would be consumed close to the source. A large amount of electricity has to be transmitted between supply and demand centres leading to several problems associated with the integration with the national power grid system, including grid investment, grid safety and grid interconnection.2.1. Power grid investmentAlthough the two state grid companies-(SGCC) State Grid Corporation of China and (CSG) China Southern Grid - have invested heavily in grid construction, China’s powe r grid is still insufficient to cope with increasing demand. For example, some coal-fired plants in Jiangsu, which is one of the largest electricity consumers in China, had to drop the load ratio to 60 percent against the international standard of 80percent due to the limited transmission capacity [16]. This situation is a result of an imbalanced investment between power grid construction and power generation capacity. For example, during the Eighth Five-Year Plan, Ninth Five-Year Plan and Tenth Five-Year Plan,1 power grid investments accounted for 13.7%, 37.3% and 30% of total investment in the electricity sector, respectively. The ratio further increased from 31.1% in 2005 to 45.94% in 2008, the cumulative investment in the power grid is still significantly lower than the investments in power generation [17]. Fig. 1 gives a comparison of the ratios of accumulative investments in power grid and power generation in China, the US, Japan, the UK and France since 1978. In most of these countries, more than half of the electric power investment has been made on grid construction. By contrast, the ratio is less than 40% in China.According to the Articles 14 and 21 of the Chinese Renewable Energy Law, the power grid operators are responsible for the grid connection of renewable energy projects. Subsidies are given subject to the length of the grid extension with standard rates. However, Mo [18] found that the subsidies were only sufficient to compensate for capital investment and corresponding interest but excluding operational and maintenance costs.Again, similar to grid connection, grid reinforcement requires significant amounts of capital investment. The Three Gorges power planthas provided an example of large-scale and long-distance electricity transmission in China. Similar to wind power, hydropower is usually situated in less developed areas. As a result, electricity transmission lines are necessary to deliver the electricity to the demand centres where the majority are located; these are the eastern coastal areas and the southern part of China. According to SGCC [19], the grid reinforcement investment of the Three Gorges power plants amounted to 34.4 billion yuan (about 5 billion US dollars). This could be a lot higher in the case of wind power due to a number of reasons. First, the total generating capacity of Three Gorges project is approximately 18.2 GW at this moment and will reach 22.4 GW when fully operating [20], whilst the total generating capacity of the massive wind farms amount to over 100 GW. Hence, more transmission capacities are absolutely necessary. Second, the Three Gorges hydropower plant is located in central China. A number of transmission paths are available, such as the 500 kV DC transmission lines to Shanghai (with a length of 1100 km), Guangzhou (located in Guangdong province, with a length of 1000 km) and Changzhou (located in Jiangsu province, with a length of 1000 km) with a transmission capacity of 3 GW each and the 500 kV AC transmission lines to central China with transmission capacity of 12 GW. By contrast, the majority of wind farm bases, which are located in the northern part of China, are far away from the load centres. For example, Jiuquan locatedin Gansu has a planned generation capacity of 20 GW. The distances from Jiuquan to the demand centres of the Central China grid and the Eastern China grid are 1500 km and 2500 km, respectively. For Xinjiang, the distances are even longer at 2500 km and 4000 km, respectively. As a result, longer transmission lines are required. Fig. 2 depicts the demand centres and wind farms in detail.2.2. Grid safetyThe second problem is related to grid safety. The large-scale penetration of wind electricity leads to voltage instability, flickers and voltage asymmetry which are likely to cause severe damage to the stability of the power grid [21]. For example, voltage stability is a key issue in the grid impact studies of wind power integration. During the continuous operation of wind turbines, a large amount of reactive power is absorbed, which lead to voltage stability deterioration [22]. Furthermore, the significant changes in power supply from wind might damage the power quality [23]. Hence, additional regulation capacity would be needed. However, in a power system with the majority of its power from base load provider, the requirements cannot be met easily [24]. In addition, the possible expansion of existing transmission lines would be necessary since integration of large-scale wind would cause congestion and other grid safety problems in the existing transmission system. For example, Holttinen [23] summarized the majorimpacts of wind power integration on the power grid at the temporal level (the impacts of power outputs at second, minute to year level on the power grid operation) and the spatial level (the impact on local, regional and national power grid). Besides the impacts mentioned above, the authors highlight other impacts such as distribution efficiency, voltage management and adequacy of power on the integration of wind power [23].One of the grid safety problems caused by wind power is reported by the (SERC) State Electricity Regulatory Commission [25]. In February and April of 2011, three large-scale wind power drop-off accidents in Gansu (twice) and Hebei caused power losses of 840.43 MW, 1006.223 MW and 854 MW, respectively, which accounted for 54.4%, 54.17% and 48.5% of the total wind powered outputs. The massive shutdown of wind turbines resulted in serious operational difficulties as frequency dropped to 49.854 Hz, 49.815 Hz and 49.95 Hz in the corresponding regional power grids.The Chinese Renewable Energy Law requires the power grid operators to coordinate the integration of windmills and accept all of the wind powered electricity. However, the power grid companies have been reluctant to do so due to the above mentioned problems as well as technical and economic reasons. For instance, more than one third of the wind turbines in China, amounting to 4 GW capacity, were not connectedto the power grid by the end of 2008 [17]. Given that the national grid in China is exclusively controlled by the power companies –SGCC and CSG - the willingness of these companies to integrate wind energy into the electricity generation systems is critical.2.3. The interconnection of provincial and regional power gridsThe interconnection of trans-regional power grids started at the end of 1980s. A (HVDC) high voltage direct current transmission line was established to link the Gezhouba2 dam with Shanghai which signifies the beginning of regional power grids interconnection. In 2001, two regional power grids, the North China Power Grid and Northeast China Power Grid were interconnected. This was followed by the interconnection of the Central China Power Grid and the North China Power Grid in 2003. In 2005, two other interconnection agreements were made between the South China Power Grid with North, Northeast and Central China Power Grid, and the Northwest China Power Grid and the Central China Power Grid. Finally, in 2009, the interconnection of Central China Power Grid and the East China Power Grid was made. In today’s China, the Chinese power transmission systems are composed of 330 kV and 500 kV transmission lines as the backbone and six interconnected regional power grids and one Tibet power grid [26].It seems that the interconnectivity of regional power grids would help the delivery of wind powered outputs from wind-rich regions todemand centres. However, administrative and technical barriers still exist. First, the interconnectivity among regions is always considered as a backup to contingencies, and could not support the large-scale, long-distance electricity transmission [27]. In addition, the construction of transmission systems is far behind the expansion of wind power. The delivery of large amounts of wind power would be difficult due to limited transmission capacity. Furthermore, the quantity of inter-regional electricity transmission is fixed [27]. Additional wind power in the inter-regional transmission might have to go through complex administrative procedures and may result in profit reductions of conventional power plants.3. Are the backup systems geographically available and technically feasible?Power system operators maintain the security of power supply by holding power reserve capacities in operation. Although terminologies used in the classification of power reserves vary among countries [28], power reserves are always used to keep the production and generation in balance under a range of circumstances, including power plant outages, uncertain variations in load and fluctuations in power generations (such as wind) [29]. As wind speed varies on all time scales (e.g. from seconds to minutes and from months to years), the integration of fluctuating wind power generation induces additional system balancing requirements onthe operational timescale [29].A number of studies have examined the approaches to stabilize the electricity output from wind power plants. For example, Belanger and Gagnon [30] conducted a study on the compensation of wind power fluctuations by using hydropower in Canada. Nema et al. [31] discussed the application of wind combined solar PV power generation systems and concluded that the hybrid energy system was a viable alternative to current power supply systems in remote areas. In China, He et al. [2]investigated the choices of combined power generation systems. The combinations of wind-hydro, wind-diesel, wind-solar and wind-gas power were evaluated respectively. They found that, for instance, the wind-diesel hybrid systems were used at remote areas and isolated islands. This is because the wind-diesel hybrid systems have lower generation efficiency and higher generation costs compared to other generation systems. Currently, the wind-solar hybrid systems are not economically viable for large-scale application; thus, these systems have either been used at remote areas with limited electricity demand (e.g. Gansu Subei and Qinghai Tiansuo) or for lighting in some coastal cities [2]. Liu et al. [32] adopted the EnergyPLAN model to investigate the maximum wind power penetration level in the Chinese power system. The authors derived a conclusion that approximately 26% of national power demand could be supplied by wind power by the end of 2007. However, theauthors fail to explain the provision of power reserves at different time scales due to wind power integration.Because of the smoothing effects of dispersing wind turbines at different locations (as exemplified by Drake and Hubacek [33] for the U.K., Roques [34] for the E.U. and Kempton et al. [35] for the U.S.), the integration of wind power has a very small impact on the primary reserves which are available from seconds to minutes [36]. However, the increased reserve requirements are considerable on secondary reserves (available within 10–15 min) which mainly consist of hydropower plants and gas turbine power plants [29]. Besides, the long-term reserves, which are used to restore secondary reserves after a major power deficit, will be in operation to keep power production and consumption in balance for a longer timescale (from several minutes to several hours). In the following subsection, we examine the availability of power plants providing secondary and long-term reserves and investigate the viability of energy storage system in China.中文中国的风力发电–梦想还是现实？胡巴切克摘要经过近几年风力发电能力的巨大增长，中国现在拥有44.7吉瓦的风力发电。