风力发电中英文翻译
风力发电对电力系统的影响
简奥斯丁，费力克斯
（电力系统及发电设备控制和仿真国家重点实验室，纽约市曼哈顿区）
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）。世界范围内十三个国家现在可以算是达到1000兆瓦的风力发电能力，法国和加拿大在2006达到这一阈值。如图1所示，直到2006年12月世界累计装机容量前10名[2]。
图1 到2006年12月世界累计装机容量
中国开始发展风电很晚。只有在90年代它才走向市场化的发展和规模建设。这些年新增累积装机容量如图2显示。单一机组容量从100千瓦，200千瓦，300千瓦600
千瓦，750千瓦，1500千瓦逐步增加。
图2 在中国累计和新增加安装的风力发电能力
在2006年中国通过安装风能的1347兆瓦，增加了一倍以上的总量容量，比去年的数值增长了70%。这给中国带来多达2604兆瓦的能力，使中国成为世界第六个最大的市场。中国市场在2006年大幅增长，这预计将继续增长并加快增长。根据经批准的和在建设中的项目，在2007年将安装超过1500兆瓦。到2010年底在中国的风电目标为5000兆瓦[3]。
3.风力发电项目的特点
从风能的角度来看，风能资源的最显特点是其变化性。风电场输出的随机变化主要根源于风速的波动和方向。无论是地理性和时间性，风是很易变的。此外，无论是在空间和时间上，这种变化性持续的范围非常广泛。
图3.布鲁克海文国家实验室工作的基础上的农场风谱图由于时间和高度的功能，风速不断变化。风变化的时间尺度显示在图3的风力频谱图上[4]。在一秒到分钟的范围阵风引起动荡的高峰。每日的峰值取决于每天的风速变化和天气高峰取决于天气变化，通常因每天或每周而异，但也包括季节性周期。
从电力系统的角度来看，湍流高峰可能会影响风力发电的电能质量。然而，昼夜和天气的高峰，可能会影响长期的电力系统的平衡，在这样的系统中风速预测起着显著作用。
另一个重要问题是风能资源的长期变化。应知道加速到中心高度的风来计算风电场的输出。大量风速测量表明，风速在一年中大多数是柔和的，介于0和25米/秒的概率是相当大的；年均风速受制于威布尔分布[5]，如公式（1）。
(1)
其中：V是平均风速；k为形状参数；c是尺度参数。
风力发电机的输出之间的关系PW和风速集线器V的高度可以近似表示为风力发电机的输出与风速或分段函数的曲线，如公式（2）。
(2)
其中：PW是额定功率的风力发电机组的输出；V是风速达枢纽的高度VCI是停机风速；VCO被切出风速；VR被评为风速。
4.风力发电对电力系统的影响
在电力系统中风力发电面临大型风电场对电网一体化的基本技术限制。风力发电对电力系统的影响包括有效功和无效功，电压，系统稳定性，电能质量，短路容量和基础设施的特点由于高容量的风力发电的动态和随机性能。在技术上，它通过以下方式影响和必须详细研究：
（1）有功和无功流
风力发电是一个间歇性和随机的电源，将功率流复杂化。由于为了捕获更多的风能能源，许多风电场建成远离负荷中心，总有传输风力发电一些的障碍。当引进额外的风力发电时一些传输或配电线路和其他电气设备可能过载。因此，应确保互相连接传输或配电线路不过载。有功和无功要求，都应予以调查。无功功率应不仅在PCC中产生，但也通过整个网络产生，并应本地补偿[6]。
用于常规发电机的分析的方法是确定的，而忽略了不确定性的风速和负荷预测。因此，概率性的方法是比较适合风力发电的。约束以概率形式描述，并且预期参数值，如电压和功率，可以被计算。
（2）电压调节
一旦风电场已经确定了其地点，连接到电网的点必须确定。对于小型风力发电场，可以在低电压下连接，从而节省了开关设备、电缆和变压器的成本。如果拟议的发展
规模太大导致不可以与当地分布电压的连接，进而不能满足较高的电压传输网络的需要[7]。
在电力系统中随着风力发电安装容量的增加，风力发电的变化引起电压变化，特别是如果并入电网，这可能不是专门设计用于迎合重要和可能快速变化的负载，这是由风力发电变化引起的。因此，需要采取监管措施，使电压保持在指定的范围内。然而，为了控制电压，这可能导致增加对无功功率的辅助服务[8]。
（3）系统的稳定性
在风力发电的电力系统中，电压稳定和频率的稳定性都受到风功率集成影响，这不仅是因为风力发电的加入将改变流量分布，也因为风力发电机与传统的同步机无论是在稳态或瞬态状态时相比表现不同[9]。
对于目前的风力发电场，当发生干扰时，保护操作通常是切断风电场之间的连接电网。因此，在这种时刻的暂态稳定是非常重要的，尤其是当大型风电场的有机结合时最为重要。然而，由于电网结构，风也可能使电源集成系统的瞬态稳定性差。因此，不同的电力系统，暂态稳定性应分别进行分析。
固定速度的风力涡轮机输出有功功率时，它吸收无功功率。“风电场无功功率的整体需求是相当大，从而导致减少在PCC附近地区的电压稳定。与此相反，双馈变速风力发电机组对无功功率有一定的控制能力。根据不同的操作和控制计划，这种风力发电机组可以吸收或输出无功功率控制电压，有利于电压稳定。电压稳定也与短路容量相关，传输的PCC行比R / X和在风力发电场使用的无功补偿方法有关。
（4）电能质量
风力发电的波动和相关电源（AC或DC）的传输、供电质量有直接的影响。结果，大量的电压波动，可能会导致电压在调控范围外变化，以及违反闪烁和其他电源的质量标准。在连续的运行和开关操作，风力发电机组，引起电压波动和闪烁，这些因素是风力发电影响电网电能质量的主要因素。对于变速风力涡轮机和恒定频率，转换器造成的谐波问题，也应考虑。
风力涡轮机对电网干扰有不同的原因，其中大多原因是风力机本体。有关参数列于表1[10]。平均发电量，湍流强度及风切变与气象和地理条件因素相关。所有其他的原因不仅归咎于电器元件的特点，如发电机，变压器等，也是转子和传动系统的空气动力学和机械性能的原因。涡轮形式（即变量与主要固定的速度档位与节距调节）对风力涡轮机和风力发电场的电能质量特性有重要性。
闪烁是由风力发电机组的有功功率或无功功率的的波动造成的。固定速度的风力
发电机闪烁的主要原因是塔的尾流。而变速风力发电机，平滑了快速功率波动，塔的尾流不影响输出功率。因此，变速风力发电机组的闪烁一般比定速闪烁风力发电机低。
表1.风力发电机和风力发电厂对电网造成的影响
参数原因
电压升高电能生产
开关操作
塔影效应
电压波动和闪烁叶片调节误差
偏航误差
风切变
风速波动
谐波变频器
晶闸管控制器
电压峰值和谷值开关操作
（5）短路容量
往往是大多数的风力发电场远离负荷中心建造，这意味着他们之间和其他间的电力系统的电气之间的距离，是相当远的。有一常理说，长电距离，使电压变化较大，但短路问题少[11]。
然而，风力发电场将能够给未来的电力系统运行的短路电流计算带来越来越重要的影响。原因是双重的。一个是上述的事实，风力发电网站通常是远离的传统的电力中心。这意味着短路电流的分布可能产生了很大的变化，导致一个完全不同的短路容量地图。其他事实的原因是，今天，越来越多的风力发电，特别是以所谓的大型风力发电场（数百兆瓦）的形式。在风电场大量的个别单位连接在一起，总代能力将大大上升。
风电场对相邻节点短路能力有很大影响，然而对远离PCC节点的影响不大[9]。因此，当具有大容量的风场并入电网时，相邻变压器和交换机的容量可能需要增加。应该进一步研究的是：如何判断风力发电对现有网络上的电气设备短路电流额定值的影响。
（6）频率调整
为了在规定的标准范围内控制电力系统频率，要求一些发电厂向电网公司提供频率控制配套服务。然而，风力发电量总额的增加，其变化频率输出是一个很重要的影响[8]。
（7）保护
电流在风电场和电网之间的流动是双向的，这是在保护的设计和配置应予以考虑的。无论风力发电机采用何种发电机，风电场的整合将增加电网故障水平，进而影响原有的电网保护装置继电器的设置。这可能需要增加新的保护装置或修改原有保护设备的继电器的设置。尤其是如果风电场连接到分配网络，断路器可能在风电场装机容量增加时产生超负荷[8]。
5.减轻风力发电的影响的对策
无功补偿设备的应用，如静止无功补偿（SVC）和静止同步补偿器（STATCOM）在风力发电中减轻其对电力系统的影响起着重要作用。为了保持电压等级，电网公司可以提供额外的或升级的电压控制设施。无功补偿设备应该安装在风电场升压变电站，这具有快速响应特性，并且可不断调节，如在SVC和STATCOM等。为了减少风力发电造成的电压波动和闪烁，既需要速度控制应加以改善，以便和俯仰角控制最大限度地减少了风力发电机的输出波动，而风力发电机的输出最大化。同时，如在风场安装辅助设备SVC和储能装置也可以减轻电压波动和闪烁。在大多数情况下，快速作用无功补偿设备，包括SVC和STATCOM，应被纳入为提高网络的暂态稳定的设备之中。
从风力发电方面，它可以通过不断的功率因数控制或恒压控制提高电力系统的电压稳定增加风力发电的渗透。从电网方面，这对加强和改变目前的网络具有重要意义。电压源换流器系统（VSC）为基础的高压直流输电（VSC-HVDC系统）是一个不需要任何额外赔偿的传输系统，因为这是转换器的控制固有的[13]。因此，它将是一个很好的工具，它使风力发电成一个网络，即使在一个弱网络中，无需提高点短路比，也能实现。VSC-HVDC的有功功率控制能力，然后是一个完美的处理有源功率/频率控制的工具。它有能力以一个很好的方式处理风电并足以快速反应抵消电压变化，它可以提高系统的稳定性和电能质量。
6.结论
距今25年，风能已经经过很长的时间，它很可能会在未来20年继续推进。有许多关于整合风力发电系统的运作和发展的问题。虽然风力发电取代了产生相当数量能量的传统植物，关注点都集中在了风力发电和电网之间的相互作用上。本文提供了一个概览风力发电对电力系统的影响和相应的对策建议来处理这些问题，为了适应风在电力系统的发电。
参考文献
[1] EWEA. Wind force 12[EB/OL].
[2] GWEC. Global wind energy markets continue to boom-2006 another record year[EB/OL].
[3] Liu Yan, Wang Wei wind power information Technology. 2007
[4] Burton T, Sharpe D, Jenkins N,et al. Wind energy handbook[M]. Chichester:John Wiley & Sons Ltd,
2001
[5] Bowden G J, Barker P R, Shestopal VO, et al. Weibull distribution function[J]. Wind Engineering,
1983, 7(2):85-98
[6] Fan Zhenyu, Enslin J H R. Challenges, principles and issues relating to the development of wind
power in China[C]. IEEE PES PSCE, 2006:748-754
[7] O'Gorman , Redfern M A. The difficulties of connecting renewable generation into utility
networks[C]. IEEE Power Engineering Society General Meeting, 2003, 3:1466-1471
[8] Wang Wei sheng, Chen Mozi. Towards the integrating wind power into power grid in China[J].
Electricity, 2004, (4):49-53
[9] Chi Yong ning, Liu Yan hua, Wang Wei sheng, et al. Study on impact of wind power integration on
power system[J]. Power System Technology, 2007, 31(3):77-81
[10] Ackermann T. Wind power in power systems[M]. Chichester:John Wiley & Sons Ltd, 2005
[11] Kumano T. A short circuit study of a wind farm considering mechanical torque fluctuation[C]. IEEE
Power Engineering Society General Meeting, 2006:1-6
[12] Strbac G, Shakoor A, Black M, et al. Impact of wind generation on the operation and development of
the UK electricity systems[J]. Electric Power Systems Research, 2007, 77(9):1214-1227
[13] Eriksson K, Liljegren C, Sobrink K. HVDC light experience sapplicable for power transmission
from offshore wind power parks[EB/OL].
附件2：外文原文
Influence Research of Wind Power Generation on Power Systems
Jane Austen，Kurt Felix
（State Key Lab of Control and Simulation of Power Systems and Generation Equipments，Manhattan District，New York，United States）
Abstract
Wind power generation is always weather dependent and has the trend of being integrated to power systems as the form of large-scale wind farms, which influences on power systems. Since the power network was not designed specifically to accommodate this type of generation, there are inevitably some points at which modifications must be executed if existing standards of electricity supply are to be maintained. This paper discusses in general terms the problems which are encountered by the developers of wind power generation projects and by utility grids when dealing with projects to integrate wind farms to power systems. The influence includes active and reactive power flow, voltage, system stability, power quality, short-circuit capacity, system reserve, frequency and protection due to the characteristics of high-capacity, dynamic and stochastic performance of wind power generation. Corresponding countermeasures to handle these issues are recommended in order to accommodate wind power generation in power systems.
Keywords: Wind power generation；Power system；Influence；Wind farms
1. Introduction
There is widespread acceptance that renewable generation is the future of electricity supply. Generation based on fossil fuels is not sustainable as power electricity is being consumed rapidly. On the contrary, wind power has attracted much attention as a promising renewable energy resource. It has potential benefits in curbing emissions and reducing the consumption of irreplaceable fuel reserves when the demand for power electricity has been steadily growing due to the industrial developments and the growth of the economy in most parts of the world.
Wind power generation is becoming more and more popular while the large-scale wind farm (hundreds of megawatts) is the mainstream one. During 2006, the world’s installed wind capacity reached 74 223 MW, up from 59 091 MW in 2005,which include wind energy developments in more than 70 countries around the world. The tremendous growth in 2006 shows that decision makers are starting to take seriously the benefits that wind energy development can bring.
There are no technical, economic or resource barriers to supplying 12% of the world’s electricity needs with wind power alone by 2020, and this against the challenging backdrop of a projected two thirds increase of electricity demand by that date. The report is a crucial tool in the race to cut greenhouse gas emissions as 12% electricity from a total of 1 250 GW of wind power installed by 2020 will save a cumulative 10771 million tons of CO2[1].
Large-scale wind farms connected to power systems have characteristics of high capacity, dynamic and stochastic performance, which challenges system security and reliability. While providing the clean power for power systems, wind farms will also bring about some unfavorable influence on power systems. With the expansion of wind power generation and the increase of wind power ratio in a power system, the influence will likely become the technical barriers for wind power integration. Therefore, the influence should be discussed and the countermeasures to overcome these issues should be proposed.
According to the issues mentioned above, this paper discusses in general terms the problems which are encountered by the developers of wind power generation projects and by utility grids when dealing with projects to integrate wind farms to power systems. Due to the characteristics of high-capacity, dynamic and stochastic performance of wind power generation, the influence includes active and reactive power flow, voltage, system stability,
power quality, short-circuit capacity, system reserve, frequency and protection. After that, corresponding countermeasures to handle these problems are recommended in order to accommodate wind power generation in power systems.
2. Development situation of wind power generation
From the report of the Global Wind Energy Council (GWEC), the countries with the highest total installed capacity are Germany (20 621 MW), Spain (11 615MW), the USA (11603MW), India(6270 MW) and Denmark (3 136 MW). Thirteen countries around the world can now be counted among those with over 1000 MW of wind capacity, with France and Canada reaching this threshold in 2006. Fig.1 shows the top 10 cumulative installed capacity of the world until December, 2006[2].
Fig. 1 Top 10 cumulative installed capacity of the world until December,2006 China started to develop wind power very late. It stepped into the stage of commercialized development and scale construction only in 1990s. Accumulated and newly added installed generating capacity over the years is shown in Fig.2.The single-unit capacity increased from 100 kW, 200 kW, and 300 kW to 600 kW, 750 kW, and 1500 kW step by step.
China doubled more than its total installed capacity by installing 1 347 MW of wind energy i n 2006, a 70% increase from last year’s figure. This brings China up to 2 604 MW of capacity, making it the sixth largest market world wide. the Chinese market has grown substantially in 2006, and this growth is expected to continue and speed up. According to the list of approved projects and those under construction, more than 1 500 MW will be installed in 2007. The goal for wind power in China by the end of 2010 is 5000 MW[3].
Fig. 2 Accumulative and newly-added installed capacity of wind power in China
3. Characteristics of wind power generation
From the point of view of wind energy, the most striking characteristic of the wind resource is its variability. The stochastic variation of wind farms outputs root mainly in fluctuation of the wind speeds and directions. The wind is highly variable, both geographically and temporally. Furthermore this variability persists over a very wide range of scales, both in space and time.
Fig. 3 Wind spectrum farm Brookhaven based on work by van der Hoven The wind speed varies continuously as a function of time and height. The time scales of wind variations are presented in Fig.3 as a wind frequency spectrum[4]. The turbulent peak is caused by gusts in the sub second to minute range. The diurnal peak depends on daily wind speed variations and the synoptic peak depends on changing weather patterns, which typically vary daily to weekly but include also seasonal cycles.
From a power system perspective, the turbulent peak may affect the power quality of wind power generation. The influence of turbulences on power quality depends very much on the turbine technology applied. Variable-speed wind turbines, for instance, may absorb short-term power variations by the immediate storage of energy in the rotating masses of
wind turbine drive trains. That means that the power output is smoother than strongly grid-coupled turbines, fixed-speed wind turbines. Diurnal and synoptic peaks, however, may affect the long-term balancing of power system, in which wind speed forecasts plays a significant role.
Another important issue is the long-term variations of the wind resources. The wind speed up to the height of the hub should be known to calculate the wind farm output. A number of measurements of wind speeds show that wind speeds are mostly mild in a year; their probabilities between 0 and 25m/s are considerable; most of the average annual wind speeds subject to the Wei bull distribution[5], as in formula(1).
(1)
Where: v is average wind speed; k is shape parameter; c is scale parameter.
The relationship between the wind turbine output Pw and the wind speed up to the height of the hub v can be expressed approximately as the curve of wind turbine’s outputs vs. wind speed or a subsection function, as in formula (2).
(2)
Where: P w is rated output of the wind turbine; v is wind speed up to the height of the hub; V CI is cut-in wind speed; V CO is cut-out wind speed; V R is rated wind speed.
4. Influence of wind power generation on power systems
High penetration of wind power in the power systems faces fundamental technical limits with regard to the integration of large-scale wind farms to the grid. The influence of wind power generation on power systems includes active and reactive power flow, voltage, system stability, power quality, short-circuit capacity, system reserve and infrastructure due to the characteristics of high-capacity, dynamic and stochastic performance of wind power generation. Technically, it influences the gird in the following ways and has to be studied in detail:
（1）Active and Reactive Power Flow
Wind power is a kind of intermittent and stochastic power source, which will complicate the power flow. Because many wind farms are built far away from load centers
in order to capture more wind energy, there is always some obstacle of transmitting wind power. Some transmission or distribution lines and other electrical equipments may be over-loaded when the additional wind power generation is introduced. So it should be ensured that the interconnecting transmission or distribution lines will not be over-loaded. Both active and reactive power requirements should be investigated. Reactive power should be generated not only at PCC, but also throughout the network, and should be compensated locally[6].
The methods utilized for analysis of conventional generators are certain and ignore the uncertainty of wind speed and load forecasts. Therefore, the probabilistic method is more suitable for wind power generation. This model is based on the wind speed distribution, such as formula (1). The constraints are described by probabilistic forms and the expected values of parameters, such as voltages and powers can be computed.
（2）V oltage Regulation
Once a wind farm has identified its site, the point at which connection to the grid must be identified. Small wind farm can connect at lower voltage, thereby saving on switchgear, cable and transformer costs. If the size of the proposed development is too large to be connected at the local distribution voltage, access to the transmission network at a higher voltage is required[7].
After failures, if the transient unstability does not occur in power systems, some wind turbines shut down due to their low voltage protections. Then outputs of wind farms decrease, which means that the power system lose reactive loads. Therefore the voltage levels climb up, even beyond the upper limits of wind farms buses.
Capacitors are the common reactive power compensation methods. When voltage levels dropdown, the amount of compensation decreases much. However the reactive power demands increase when the asynchronous machines are utilized in wind farms. So voltage levels drop down more, even beyond the lower limits of wind farms buses.
With the increase of wind power installed capacity in power systems, the variability of wind power generation causes variability of voltage level, particularly if integrated into the grid which might not be specifically designed to cater for the significant and possibly rapid load variations (compared with normal customer load variation) caused by highly variable wind power generation. Therefore, the regulatory measures are needed to maintain the
voltage level in a specified range. However, the variability of wind power generation is not a low probability; this could result in an increased requirement for reactive power ancillary services to manage voltage control[8].
（3）System Stability
In the power system with high wind power penetration, the transient stability, voltage stability and frequency stability are all influenced by the wind power integration not only because the injection of wind power will change the power flow distribution, transferred power of each transmission line and total inertia of the whole power system, but also because the wind turbine generators perform differently in either steady-state or transient-state compared with the conventional synchronous machine[9].
For current operation of wind farms, protections usually cut off the connections between wind farms and the grid when great disturbances occur. This is equivalent to arouse new generators tripping disturbance after the great disturbances. So the transient stability in such moment is very crucial, especially when large-scale wind farms are integrated. Compared the variable-speed wind turbine based on the doubly-fed induction generator (DFIG) with the fixed-speed wind turbine based on the induction motor, the former is more robust after short-circuit failures and can strengthen system stability with keeping enough stability margin. However, wind power integration may also make the system transient stability worse due to the grid structure. Therefore, transient stabilities of different power systems should be analyzed respectively.
The fixed-speed wind turbine absorbs the reactive power when outputting the active power. The whole demand of a wind farm for the reactive power is considerable, which lead to the decrease of the voltage stability in the area near PCC. On the contrary, the variable-speed wind turbine based on DFIG has certain ability to control the reactive power. According to different operation and control schemes, this wind turbine can absorb or output the reactive power to control the voltage, which benefits the voltage stability. The voltage stability is also related with the short-circuit capacity of PCC, transmission line ratios of R/X and reactive compensation methods utilized of wind farms.
（4）Power Quality
Fluctuations in the wind power and the associated power transport (AC or DC), have direct consequences to the power supply quality. As a result, large voltage fluctuations may
result in voltage variations outside the regulation limits, as well as violations on flicker and other power quality standards. During the continuous operation and switching operation, wind turbine causes voltage fluctuation and flicker, which are main concerns of unfavorable influence of wind power generation on power quality of the grid. For wind turbine of variable-speed and constant-frequency, harmonic issue caused by converters should also be considered.
Tab. 1 Crid interferences caused by wind turbines and wind farms
The grid interferences of wind turbines or wind farms have different causes, which are mostly turbine-specific. The relevant parameters are listed in Tab.1[10]. Average power production, turbulence intensity and wind shear refer to causes that are determined by meteorological and geographical conditions. All the other causes are attributed not only by the characteristics of the electrical components, such as generators, transformers and so on, but also by the aerodynamic and mechanical behavior of the rotor and drive train. The turbine type (i.e. variable versus fixed speed stall versus pitch-regulated) is of major importance to the power quality characteristics of wind turbines and wind farms.
Flicker is caused by the fluctuation of active and/or reactive power of wind turbines. The main reason for flicker in fixed-speed wind turbines is the wake of the tower while for variable-speed wind turbines, fast power fluctuations are smoothed and the wake of the tower does not affect power output. Therefore, the flicker of variable-speed wind turbines is in general lower than the flicker of fixed-speed wind turbines. In wind farms, power fluctuations are smoothed because of the fact wind turbines are correlated.
（5）Short-Circuit Capacity.
The majority of the wind power farms tend to be constructed remote from the load
center, which means that electrical distance between them and the other part of the power system is rather long. There is a common sense that long electrical distance makes voltage variation bigger but short circuit problem smaller[11].
However, wind power farms will be able to give more and more significant effects on the calculation of short circuit current in future power system operation. The reason is twofold. One is the above stated fact that wind power generation site is usually apart from the conventional electrical power center. It implies that the distribution of short circuit current might make a drastic change, leading to a completely different short circuit capacity map. The other reason is the fact that more and more wind power generation today are particularly in the form of so called large-scale wind farms (hundreds of megawatts). In wind farms a substantial number of individual units are connected together, and the total generation capacity will greatly rise up.
Wind farms have great influence on the short circuit capacities of adjacent nodes while the nodes far apart from PCC are little influenced[9]. Therefore, when wind farms with huge capacities are integrated into the grid, capacities of adjacent transformers and switches may need to be increased. It should be studied further how to determine the influence of wind power generation on the short circuit current ratings of existing electrical equipments on the network.
（6）System Reserve.
Meanwhile, system load forecast will potentially become less accurate as the amount of wind power generation increases, which in turn influence power system operational scheme and unit commitment. In the case of generation reserve forecasts, this could translate into higher reserve level requirements to cover uncertainties in the availability of wind power generation[8].
（7）Frequency Regulation.
In order to control power system frequency within defined standards, grid corporations require some power plants to provide frequency control ancillary services. However, as the total amount of wind power generation increases, variation in its output will have a more significant impact on the frequency[8].
（8）Protection.
As for any proposed expansion of a utility grid, there are problems to be addressed
with each application for connection. For connection to the distribution system, the proposed generation must have a relatively low capacity. In general, that part of the network is radial and the protection would be graded to expect fault current to flow outwards from the hulk supply point. Introduction of a generator into the radial network means that fault current can now be supplied which does not flow in the expected direction. A detailed check of the protection settings with the proposed generator in the network model is therefore required. The results of this check may show that the protection will function quite adequately as it is. At the other extreme, it may show that the existing relays cannot protect the network while the new generation and a redesign of the protection is necessary[7].
The power flows between wind farms and the grid are bidirectional, which should be considered during the protections design and configuration. Whatever kind of generators are adopted in wind turbines, integration of a wind farm will increase the fault level of grid and furthermore affect the relay settings of original protection devices of grid. It is probably necessary to add new protection devices and/or modify the relay settings of original protection devices. Particularly if wind farms are connected into distribution networks, overloading of circuit breakers may occur with the increase of installed capacity of wind farm[8].
5. Countermeasures to mitigate wind power generation influence
The applications of the reactive compensation equipments, such as static var compensator (SVC) and static synchronous compensator (STATCOM) play an important role in wind power generation to mitigate its influence on the power system. In order to maintain the voltage level, the grid corporation may provide additional or upgraded voltage control facilities. Reactive compensation equipments should be installed in the step-up substation of wind farm, which has a fast response characteristic and can be regulated continuously, such as SVC and STATCOM, etc. In order to mitigate voltage fluctuation and flicker caused by wind power generation, both speed control and pitch angle control should be improved so as to minimize the fluctuation of wind turbine output while maximizing the output of wind turbine. Meanwhile, installation of auxiliary devices on wind farm such as SVC and energy storage device can also mitigate both voltage fluctuation and flicker. In most cases, fast-acting reactive-power compensation equipment, including SVC and STATCOM, should be included for improving the transient stability of the network.
From the wind power generation side, it can improve the voltage stability of the power system and increase wind power penetration by the constant power factor control or constant voltage control. From the grid side, it is of significance to reinforce and change the current network. V oltage source converter (VSC) based HVDC (VSC-HVDC) is a transmission system that does not require any additional compensation, as this is inherent in the control of the converters[13]. It will therefore be an excellent tool for bringing wind power into a network, even at weak points in a network and without having to improve the short-circuit ratio. The active power control capability of VSC-HVDC could then be a perfect tool for handling active power/frequency control. It is capable of handling wind power and of reacting rapidly enough to counteract voltage variations in an excellent way, which can improve the system stability and power quality.
6. Conclusion
Wind energy has come a long way since the prototypes of just 25 years ago, and it will probably continue to advance over the next twenty years. There are a number of issues associated with integration of wind power in system operation and development. Although penetration of wind power generation may displace significant amount of energy produced by conventional plants, concerns are focused on the interaction between wind power generation and the grid. This paper has provided an overview of the influence of wind power generation on power systems and recommended corresponding countermeasures to handle these issues in order to accommodate wind power generation in power systems.
Reference
[1] EWEA. Wind force 12[EB/OL].
[2] GWEC. Global wind energy markets continue to boom-2006 another record year[EB/OL].
[3] Liu Yan, Wang Wei wind power information Technology. 2007
[4] Burton T, Sharpe D, Jenkins N,et al. Wind energy handbook[M]. Chichester:John Wiley & Sons Ltd,
2001
[5] Bowden G J, Barker P R, Shestopal VO, et al. Weibull distribution function[J]. Wind Engineering,
1983, 7(2):85-98
[6] Fan Zhenyu, Enslin J H R. Challenges, principles and issues relating to the development of wind
power in China[C]. IEEE PES PSCE, 2006:748-754
[7] O'Gorman , Redfern M A. The difficulties of connecting renewable generation into utility
networks[C]. IEEE Power Engineering Society General Meeting, 2003, 3:1466-1471
[8] Wang Wei sheng, Chen Mozi. Towards the integrating wind power into power grid in China[J].
Electricity, 2004, (4):49-53
[9] Chi Yong ning, Liu Yan hua, Wang Wei sheng, et al. Study on impact of wind power integration on
power system[J]. Power System Technology, 2007, 31(3):77-81
[10] Ackermann T. Wind power in power systems[M]. Chichester:John Wiley & Sons Ltd, 2005
[11] Kumano T. A short circuit study of a wind farm considering mechanical torque fluctuation[C]. IEEE
Power Engineering Society General Meeting, 2006:1-6
[12] Strbac G, Shakoor A, Black M, et al. Impact of wind generation on the operation and development of
the UK electricity systems[J]. Electric Power Systems Research, 2007, 77(9):1214-1227
[13] Eriksson K, Liljegren C, Sobrink K. HVDC light experience sapplicable for power transmission
from offshore wind power parks[EB/OL].
花名翻译大全附带花语
花名翻译大全附带花语 中国水仙new year lily 自尊/单恋 石榴pomegranate 相思/永生 月桂victor\'s laurel 胜利/不诚实 报春花polyanthus 初恋/自作多情 木棉cotton tree 热情 紫丁香lilac 青春的回忆 吊钟lady\'s eardrops 尝试/热心 紫荆chinese redbud 故情/手足情 百合lily 纯净/神圣 紫罗兰wall flower 信任/爱的羁绊 桃花peach 被你俘虏 紫藤wistaria 沉迷的爱 杜鹃azalea 爱的快乐/节制 铃兰lily-of-the-valley 纤细/希望/纯洁牡丹tree paeony 富贵/羞怯 银杏ginkgo 长寿 芍药paeony 害羞 蝴蝶兰moth orchid 幸福/纯洁/吉祥 辛夷violet magnolia 友情/爱自然 蟹爪仙人掌christmas cactus 锦上添花玫瑰rose 爱情/爱与美 郁金香tulip 名誉/慈善/美丽 茶花common camelia 美德/谦逊
千日红common globe-amaranth 永恒的爱/不朽非洲堇african vioet 永恒的美 天人菊indian blanket 团结/协力 栀子花cape jasmine 喜悦/纯洁 木槿rose of sharon 劝告/短暂的美 风信子hyacinyh 悲哀/永远怀念 百子莲african lily 爱的来临 牵牛花morning glory 爱情/依赖 君子兰kafir lily 宝贵/高贵 荷包花lady\'s pocketbook 聚集财富 含笑花banana shrub 矜持/含蓄 非洲菊african daisy 神秘/兴奋 含羞草esnsitive plant 敏感 茉莉arabian jasmine 你属于我/亲切 猪笼草pitcher plant 财源广进 凌霄花creeper 好高骛远 树兰orchid tree 平凡而清雅 康乃馨caronation 温馨/慈祥 鸡冠花cockscomb 永生/爱美/痴情 荷花lotus 神圣/纯洁 鸢萝cypress vine 关怀/依附 菩提bo-tree 结婚/圣洁 大理花dahlia 移情别恋/优雅 圣诞百合christmas bell 温暖的心 一串红scarlet sage 热切的思念
风电专业术语英文对照及解释
风电专业术语中英对照及解释 经电气网小编整理，下面是有关风电的一些专业术语的英汉对照及解释，希望对各位有用哦。 1.风能 /wind energy 空气流动所具有的能量。 2.风能资源 /wind energy resources 大气沿地球表面流动而产生的动能资 源。 3.空气的标准状态 /standard atmospheric state 空气的标准状态是指空 气压力为101 325Pa，温度为15℃（或绝对288.15K），空气密度1.225kg/m 3 时的空气状态。 4.风速 /wind speed 空间特定点的风速为该点空气在单位时间内所流过的 距离。 5.平均风速 /average wind speed 给定时间内瞬时风速的平均值。 6.年平均风速 /annual average wind speed 时间间隔为一整年的瞬时风速 的平均值。 7.最大风速 /maximum wind speed 10分钟平均风速的最大值。 8.极大风速 /extreme wind speed 瞬时风速的最大值。 9.阵风 /gust 超过平均风速的突然和短暂的风速变化。 10.年际变化 /inter-annual variation 以30年为基数发生的变化。风速年 际变化是从第1年到第30年的年平均风速变化。 11.[风速或风功率密度]年变化 /annual variation 以年为基数发生的变化。 风速（或风功率变化）年变化是从1月到12月的月平均风速（或风功率密度）变化。 12.[风速或风功率密度]日变化 /diurnal variation 以日为基数发生的变 化。月或年的风速（或风功率密度）日变化是求出一个月或一年内，每日同一钟点风速（或风功率密度）的月平均值或年平均值，得到0点到23点的风速（或风功率密度）变化。 风切变 /wind shear 风速在垂直于风向平面内的变化。 13.风切变指数 /wind shear exponent 用于描述风速剖面线形状的幂定律指 数。 14.风速廓线 /wind speed profile, wind shear law 又称“风切变律”， 风速随离地面高度变化的数学表达式。 15.湍流强度 /turbulence intensity 标准风速偏差与平均风速的比率。用 同一组测量数据和规定的周期计算。 16.年风速频率分布 /annual wind speed frequency distribution 在观测 点一年时间内，相同的风速发生小时数之和占全年总小时数的百分比与对应风速的概率分布函数。 17.威布尔分布 /Weibull distribution 经常用于风速的概率分布函数，分 布函数取决于两个参数，控制分布宽度的形状参数和控制平均风速分布的尺度参数。 18.瑞利分布 /Rayleigh distribution 控制分布宽度的形状参数值为2的威 布尔分布，分布函数取决于一个调节参数——尺度参数，它控制平均风速的分布。 19.风功率密度 /wind power density 与风向垂直的单位面积中风所具有的
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一、材质中英文对照表 1.摇粒绒：Polar Fleece 2.珊瑚绒：coral fleece / soft terry 3.羊羔绒：Berber fleece / polyester faux sherpa 4.短毛绒：short plush 5.长毛绒：long plush 6.毛绒：fur 7.天鹅绒：velvet 8.拖把绒：cord velour 9.PV绒：PV plush 10.毛巾布：terry 11.灯芯绒：corduroy 12.双色毛绒：two-tone faux fur 13.毛线针织：knitting 14.麂皮绒：microfiber/microsuede 15.格利特：glitter 16.亮片：sequin 17.佳积布：nylex 18.尼龙布：nylon 19.汗衫布：jersey 20.沙丁布：satin 21.网布：mesh 22.帆布：canvas 23.斜纹棉布: cotton twill 24.PU 25.镜面PU：patent PU 26.平纹PU：smooth PU 27.EV A 28.点塑底：fabric with dot / skid free dot/non skid dot 29.TPR 30.PVC注塑：PVC injected 二、鞋子装饰物（ornament） 1.松紧带：elastic gore 2.魔术贴：velcro 3.电绣：embroidery 4.蝴蝶结：bow 5.爱心：heart 6.鞋带：lace 7.鞋眼：eyelet 8.人造钻石：rhinestone 9.搭带：strap 10.拉环：loop 11.毛球：POM 12.织唛标：Woven label 13.烫印：heat seal 14.贴片：patch 15.拉链：zipper 三、颜色 1. 豹纹：leopard/ cheetah 2. 斑马纹：zebra 3. 虎纹：tiger 4. 米黄色：beige 5. 桃红色：fuschia 6. 淡紫色：lilac 7. 海军蓝：Navy 8. 咖啡色：Brown 9. 迷彩：camo 10. 湖水蓝：blue atoll/ turq / lake blue 11. 格子：plaid / gingham 12. 紫色：purple 13. 灰色：grey/gray 14. 条纹：strip 15. 银光粉：neon pink 16. 金属色：metallic 17. 栗色：chestnut AI Artwork 设计稿
风力发电外文翻译
毕业设计(论文)外文资料翻译 专业：电气工程及其自动化 姓名： 学号： 外文出处：Xu, G., Sankar, L. N., “Effects of Transition, Turbulence, and Yaw on the Performance of Horizontal Axis Wind Turbines”, AIAA-2000-0048, Prepared for the 38th AIAA Aerospace Sciences Meeting and Exhibit, Reno, NV, January 10-13, 2000, p. 259-265. (用外文写) 附件： 1.外文资料翻译译文；2.外文原文。
指导教师评语： 签名： 年月日
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常--Chiong 车--Che 陈--Chen/Chan/Tan 成/程--Cheng 池--Chi 褚/楚--Chu 淳于--Chwen-yu D: 戴/代--Day/Tai 邓--Teng/Tang/Tung 狄--Ti 刁--Tiao 丁--Ting/T 董/东--Tung/Tong 窦--Tou 杜--To/Du/Too 段--Tuan 端木--Duan-mu 东郭--Tung-kuo 东方--Tung-fang E: F: 范/樊--Fan/Van 房/方--Fang 费--Fei 冯/凤/封--Fung/Fong 符/傅--Fu/Foo G: 盖--Kai 甘--Kan 高/郜--Gao/Kao 葛--Keh 耿--Keng 弓/宫/龚/恭--Kung 勾--Kou 古/谷/顾--Ku/Koo 桂--Kwei
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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。目前，利用风力发电已成为风能利用的主要形式，受到世界各国的高度重视，而且发展速度最快。 风能技术是一项高新技术，它涉及到气象学、空气动力学、结构力学、计算机技术、电子控制技术、材料学、化学、机电工程、电气工程、环境科学等十几个学科和专业，因此是一项系统技术，其难度毫不逊色于航天技术。 一、风能技术的划分： 风能技术分为大型风电技术和中小型风电技术，虽然都属于风能技术，工作原理也相同，但是却属于完全不同的两个行业：具体表现在“政策导向不同、市场不同、应用领域不同、应用技术更是不同，完全属于同种产业中的两个行业。因此，在中国风力机械行业会议上已经把大型风电和中小型风电区分出来分别对待。此外，为满足市场不同需求，延伸出来的风光互补技术不仅推动了中小型风电技术的发展，还为中小型风电开辟了新的市场。 1、大型风电技术： 我国大型风电技术与国际还有一定差距。 大型风电技术起源于丹麦、荷兰等一些欧洲国家，由于当地风能资源丰富，风电产业受到政府的助推，大型风电技术和设备的发展在国际上遥遥领先。目前我国政府也开始助推大型风电技术的发展，并出台一系列政策引导产业发展。大型风电技术都是为大型风力发电机组设计的，而大型风力发电机组应用区域对环境的要求十分严格，都是应用在风能资源丰富的资源有限的风场上，常年接受各种各样恶劣的环境考研，环境的复杂多变性，对技术的高度要求就直线上升。目前国内大型风电技术普遍还不成熟，大型风电的核心技术仍然依靠国外，国家政策的引导使国内的风电项目发疯一样在各地上马，各地都期望能借此分得一杯羹。名副其实的“疯电”借着政策的东风开始燎原之势。虽然风电项目纷纷上马，但多为配套类型，完全拥有自主知识产权的大型风电系统技术和核心技术少之又少。还需经历几年环境考验的大型风电技术才能逐渐成熟。此外，大型风电技术中发电并网的技术还在完善，一系列的问题还在制约大型风电技术的发展。 2、中小型风电技术： 我国中小型风电技术可以与国际相媲美。 在本世纪70年代中小型风电技术在我国风况资源较好的内蒙、新疆一带就已经得到了发展，最初中小型风电技术被广泛应用在送电到乡的项目中为一家一户的农牧民家用供电，随着技术的更新不断的完善与发展，不仅能单独应用还能与光电组合互补已被广泛应用于分布式独立供电。这些年来随着我国中小型风电出口的稳步提升。在国际上，我国的中小型风电技术和风光互补技术已跃居国际领先地位。 中小型风电技术成熟受自然资源限制相对较小，作为分布式独立发电效果显著不仅可以并网，而且还能结合光电形成更稳定可靠的风光互补技术，况且技术完全自主国产化。无论从技术还是价格在国际上都十分具有竞争优势；加上现在在国际已打响了中小型风电的中国品牌；“墙内开花墙外香”已愈演愈烈。在国内最具技术优势和竞争力中小型风力发电一直是被政府和政策遗忘的一个角落，究其原因，在早期国家一直把中小型风力发电定位到内蒙、新疆等偏远地区农牧民使用且归入农机类，价
公司章程翻译中英文对照
……公司章程ARTICLES OF ASSOCIATION of ……CO., LIMITED
……公司章程 ARTICLES OF ASSOCIATION OF ……CO., LIMITED 根据《中华人民共和国公司法》（以下简称《公司法》）及其他有关法律、行政法规的规定，特制定本章程。 In accordance with the PRC Company Law (hereinafter referred to as the "Company Law") and other relevant laws and regulations, these articles of association are hereby formulated. 第一章公司名称和住所 CHAPTER 1 The Name and Domicile of the Company 第一条公司名称： Article 1 The name of the Company is 第二条公司住所： Article 2 The domicile of the Company is 第二章公司经营范围 CHAPTER 2 Business Scope of the Company
第三条公司经营范围： Article 3 The business scope of the Company is (subject to approval in business license and the Administration for Industry and Commerce ) -------- 第三章公司注册资本 CHAPTER 3 The Registered Capital of the Company 第四条公司注册资本：人民币---万元。公司增加、减少及转让注册资本，由股东做 出决定。公司减少注册资本，还应当自做出决定之日起十日内通知债权人，并于三十 日内在报纸上至少公告一次，减资后的注册资本不得低于法律规定的最低限额。公司 变更注册资本应依法向登记机关办理变更登记手续。 Article 4 The registered capital of the Company is------ RMB. Resolutions on the increase, reduction or transfer of the Company's registered capital shall be made by the shareholers. The Company may reduce its registered capital according to the regulations set in these Articles of Association. Where such reduction of capital occurs, the Company shall inform its creditors of the reduction of registered capital within ten (10) days following the date on which the reduction resolution is adopted, and make at least one announcement regarding the reduction in a newspaper within thirty (30) days. After the reduction, the registered capital of the Company shall not be less than the statutory minimum limit. It shall apply
风力发电机用专业英语中文对照-全
风力发电机用专业英语中文对照 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
风力发电中英文翻译
风力发电中英文翻译 Prepared on 24 November 2020
风力发电对电力系统的影响 简奥斯丁，费力克斯 （电力系统及发电设备控制和仿真国家重点实验室，纽约市曼哈顿区） 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）。世界范围内十三个国家现在可以算是达到1000兆瓦的风力发电
风电专业术语中英文对照
风力机wind turbine 风力发电机组wind turbine generator system (WTGS) 风电场wind power station; wind farm 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 turbines) 机舱nacelle 支撑结构（风力机）support structure (for wind turbine) 关机（风力机）shutdown (for wind turbine) 紧急关机（风力机）emergency shutdown(for wind turbine) 空转（风力机）idling(for wind turbine) 锁机（风力机）blocking (for wind turbine) 停机（风力机）parking 静止standstill 制动器（风力机）brake(for wind turbine) 停机制动（风力机）parking brake (for wind turbine) 风轮转速（风力机）rotor speed (for wind turbine) 控制系统（风力机）control system (for wind turbine) 保护系统（风力发电系统）protection system (for WTGS) 设计工况design situation 载荷情况load case 外部条件（风力机）external conditions (for wind turbine) 设计极限design limits 极限状态limit state 安全寿命safe life 风速wind speed 风矢量wind velocity 额定风速（风力机）rated wind speed(for wind turbine) 切入风速cut-in wind speed 切出风速cut-out wind speed 年平均annual average 年平均风速annual average wind speed 平均风速mean wind speed 极端风速extreme wind speed 风切变wind shear 下风向down wind 上风向up wind 阵风gust 粗糙长度roughness length 湍流强度turbulence intensity 风场wind site 测量参数measurement parameters 测量位置measurement seat 最大风速maximum wind speed 风功率密度wind energy density 阵风影响gust influence
中英文对照版合同翻译样本
1.Sales Agreement The agreement, (is) made in Beijing this eighth day of August 1993 by ABC Trading Co., Ltd., a Chinese Corporation having its registered office at Beijing, the People’ Repubic of China (hereinafter called “Seller”) and International Tradi ng Co., Ltd., a New York Corporation having its registered office at New York, N.Y., U.S.A. (hereinafter called “Buyer”). 2.WITNESSETH WHEREAS, Seller is engaged in dealing of (product) and desires to sell (product)to Buyer, and WHEREAS, Buyer desires to purchase(product) from Sellers, Now, THEREFORE, it is agreed as follows: 3.Export Contract This Contract is entered into this 5th day of August 1993 between ABC and Trading Co., Ltd. (hereinafter called “Seller”) who agrees to sell, and XYZ Trading Co., Ltd. (hereinafter called “Buyer”) who agrees to buy the following goods on the following terms and condition. 4.Non-Governmental Trading Agreement No. ＿＿This Agreement was made on the＿day of＿19＿, BETWEEN ＿ (hereinafter referred to as the Seller) as the one Side and ＿ (hereinafter referred to as the Buyer) as the one other Side. WHEREAS, the Seller has agreed to sell and the buyer has agreed to buy ＿ (hereinafter referred to as the Goods ) the quantity, specification, and price of which are provided in Schedule A. IT IS HEREBY AGREED AS FOLLOWS: 5.Contract For Joint-Operation Enterprise ＿＿ COMPANY LTD., a company duly organized under the Law of ＿＿ and having its registered office at (hereinafter called “Party A”) AND ＿＿ COMPANY LTD., a company duly organized under the Law of ＿＿ and having its registered office at (hereinafter called “Party B”) Party A and Party B (hereinafter referred to as the “Parties”) agree to jointly form a Co-operation Venture Company (hereinafter referred to as the “CVC”) in accordance with “the Laws of the People’s Republic of China on Joint Ventures Using Chinese and Foreign Investment” and the “Regulations for the Implementation of the Laws of the People’s Republic of China on Joint Ventures Using Chinese and Foreign Investment” and other applicable laws and regulations. 6.MODEL CONTRACT Contract No. Date: Seller: Signed at: Address: Cable Address: Buyer: Address: Cable Address: The Seller and the Buyer have agreed to conclude the following transactions according to the terms and conditions stipulated below: https://www.360docs.net/doc/913261746.html, of Commodity: 2.Specifications: 3.Quantity: 4.Unit Price: 5.Total Price: U.S.$: 6.Packing: 7.Time of Shipment: days after receipt of L/C. 8.Loading Port & Destination Port: From via to . 9.Insurance: