wind power
中国电科院风电功率预测系统
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4 风电功率预测系统开发(Wind power prediction system development)
中国电力科学研究院
CHINA ELECTRIC POWER RESEARCH INSTITUTE
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5 结论与展望（Conclusion and expectation）
建立了基于神经网络的风电功率预测系统，即将应用于吉林电网调度中心。 A wind power prediction system based on ANN is established, and will be installed in Jilin power grid dispatch center 风电功率天前预测结果的均方根误差在15%左右。 The RMSE of day ahead prediction is around 15% 风电功率预测系统能够降低电网的运行成本，有一定的经济效益。 The wind power prediction system is helpful for saving power grid operation cost, have certain ecomonic benefit 尽快建立我国数值天气预报商业化服务，完善预测系统，提高预测精度，并开 展风电功率预测系统的应用研究。 Builting up Chinese commercial NWP service network as soon as possible,improve forecast precision, developing wind power prediction system application research.
中国电力科学研究院
CHINA ELECTRIC POWER RESEARCH INSTITUTE
风电专业英语(整理版)
风力发电机 wind turbine风电场 wind power station wind farm风力发电机组 wind turbine generator system WTGS 水平轴风力发电机 horizontal axis wind turbine垂直轴风力发电机 vertical axis wind turbine轮毂（风力发电机） hub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极端风速 extreme wind speed安全风速 survival wind speed参考风速reference wind speed风速分布 wind speed distribution瑞利分布RayLeigh distribution威布尔分布 Weibull distribution风切变 wind shear风廓线风切变律 wind profile wind shear law风切变指数wind shear exponent对数风切变律 logarithmic wind shear law风切变幂律 power law for 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湍流尺度参数turbulence scale parameter湍流惯性负区 inertial sub-range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 power density风能密度 wind energy density日变化 diurnal variation年变化 annual variation轮毂高度 hub height风能 wind energy标准大气状态 standard atmospheric state风切变影响 influence by the wind shear阵风影响 gust influence风速频率 frequency of wind speed环境 environment工作环境 operational environment气候 climate海洋性气候 ocean climate大陆性气候 continental climate露天气候 open-air climate室内气候 indoor climate极端 extreme日平均值 daily mean极端最高 extreme maximum年最高 annual maximum年最高日平均温度 annual extreme daily mean of temperature 月平均温度 mean monthly temperature空气湿度 air humidity绝对湿度 absolute humidity相对湿度 relative humidity降水 precipitation雨 rain冻雨 freezing rain霜淞 rime雨淞 glaze冰雹 hail露 dew雾 fog盐雾 salt fog雷暴 thunderstorm雪载 snow load标准大气压 standard air pressure平均海平面 mean sea level海拔 altitude辐射通量 radiant flux太阳辐射 solar radiation直接太阳辐射 direct solar radiation天空辐射 sky radiation太阳常数 solar constant太阳光谱 solar spectrum黑体 black body白体 white body温室效应 greenhouse effect环境温度 ambient temperature表面温度 surface temperature互联 interconnection输出功率output power额定功率 rated power最大功率 maximum power电网连接点 network connection point电力汇集系统 power collection system风场电器设备 site electrical facilities功率特性power performance静电功率输出 net electric power output功率系数 power performance自由流风速 free stream wind speed扫掠面积 swept area轮毂高度 hub height测量功率曲线 measurement power curve外推功率曲线 extrapolated power curve年发电量 annual energy production可利用率 availability数据组功率特性测试 data set for power performance measurement 精度 accuracy测量误差 uncertainty in measurement分组方法 method of bins测量周期 measurement period测量扇区 measurement sector日变化 diurnal variations浆距角 pitch angle距离常数 distance constant试验场地 test site气流畸变 flow distortion障碍物 obstacles复杂地形带 complex terrain风障 wind break声压级 sound pressure level声级 weighted sound pressure level; sound level 视在声功率级 apparent sound power level指向性 directivity音值 tonality声的基准面风速 acoustic reference wind speed标准风速 standardized wind speed基准高度 reference height基准粗糙长度 reference roughness length基准距离 reference distance掠射角 grazing angle风轮风轮 wind rotor风轮直径 rotor diameter风轮扫掠面积 rotor swept area风轮仰角 tilt angle of rotor shaft风轮偏航角 yawing angle of rotor shaft风轮额定转速 rated turning speed of rotor风轮最高转速 maximum turning speed of rotor风轮尾流 rotor wake尾流损失 wake losses风轮实度 rotor solidity实度损失 solidity losses叶片数 number of blades叶片 blade等截面叶片 constant chord blade变截面叶片variable chord blade叶片投影面积 projected area of blade叶片长度 length of blade叶根 root of blade叶尖tip of blade叶尖速度 tip speed浆距角 pitch angle翼型 airfoil前缘 leading edge后缘tailing edge几何弦长 geometric chord of airfoil平均几何弦长 mean geometric of airfoil气动弦线 aerodynamic chord of airfoil翼型厚度 thickness of airfoil翼型相对厚度 relative thickness of airfoil厚度函数 thickness function of airfoil中弧线 mean line弯度 degree of curvature翼型族 the family of airfoil弯度函数 curvature function of airfoil叶片根梢比 ratio of tip-section chord to root-section chord叶片展弦比 aspect ratio叶片安装角setting angle of blade叶片扭角 twist of blade叶片几何攻角 angle of attack of blade叶片损失blade losses叶尖损失tip losses颤振flutter迎风机构orientation mechanism调速机构 regulating mechanism风轮偏测式调速机构 regulating mechanism of turning wind rotor out of the wind sideward 变浆距调速机构regulating mechanism by adjusting the pitch of blade整流罩 nose cone顺浆 feathering阻尼板spoiling flap风轮空气动力特性 aerodynamic characteristics of rotor叶尖速度比 tip-speed ratio额定叶尖速度比 rated tip-speed ratio升力系数 lift coefficient阻力系数 drag coefficient推或拉力系数 thrust coefficient偏航系统滑动制动器sliding shoes偏航 yawing主动偏航active yawing被动偏航 passive yawing偏航驱动 yawing driven解缆 untwist塔架tower独立式塔架 free stand tower拉索式塔架 guyed tower塔影响效应 influence by the tower shadow<<功率特性测试>>功率特性 power performance净电功率输出 net electric power output功率系数 power coefficient自由流风速 free stream wind speed扫掠面积swept area测量功率曲线 measured power curve外推功率曲线 extrapolated power curve年发电量 annual energy production数据组 data set可利用率 availability精度 accuracy测量误差 uncertainty in measurement分组方法 method of bins测量周期 measurement period测量扇区 measurement sector距离常数 distance constant试验场地 test site气流畸变 flow distortion复杂地形地带 complex terrain指向性 directivity音值 tonality声的基准风速 acoustic reference wind speed标准风速 standardized wind speed基准高度 reference height基准粗糙长度 reference roughness基准距离 reference distance标准误差 standard uncertainty风能利用系数 rotor power coefficient力矩系数 torque coefficient额定力矩系数 rated torque coefficient起动力矩系数starting torque coefficient最大力矩系数maximum torque coefficient过载度 ratio of over load风力发电机组输出特性 output characteristic of WTGS调节特性 regulating characteristics平均噪声 average noise level机组效率efficiency of WTGS使用寿命 service life度电成本 cost per kilowatt hour of the electricity generated by WTGS 发电机同步电机 synchronous generator异步电机 asynchronous generator感应电机 induction generator转差率 slip换向器 commutator集电环 collector ring换向片 commutator segment励磁响应 excitation response制动系统制动系统 braking制动机构 brake mechanism正常制动系 normal braking system紧急制动系 emergency braking system空气制动系 air braking system液压制动系 hydraulic braking system电磁制动系 electromagnetic braking system机械制动系 mechanical braking system 辅助装置 auxiliary device制动器释放 braking releasing制动器闭合 brake setting液压缸 hydraulic cylinder溢流阀 relief valve泻油 drain齿轮马达 gear motor齿轮泵 gear pump电磁阀solenoid液压过滤器 hydraulic filter液压泵hydraulic pump液压系统 hydraulic system油冷却器 oil cooler压力控制器pressure control valve压力继电器pressure switch减压阀reducing valve安全阀 safety valve压力表pressure gauge液压油hydraulic fluid液压马达hydraulic motor油封oil seal刹车盘 brake disc刹车油 brake fluid闸衬片 brake lining传动比 transmission ratio齿轮gear齿轮副gear pair齿轮系 train of gears行星齿轮系 planetary gear train小齿轮 pinion大齿轮 wheel , gear主动齿轮 driving, gear从动齿轮 driven gear行星齿轮 planet gear行星架 planet carrier太阳轮 sun gear内齿圈 ring gear外齿轮external gear内齿轮internal中心距 center distance增速比 speed increasing ratio齿面 tooth flank模数 module齿数 number of teeth啮合干涉 meshing interference啮合 engagement, mesh齿轮的变位 addendum modification on gears变位齿轮 gears with addendum modification圆柱齿轮 cylindrical gear直齿圆柱齿轮 spur gear斜齿圆柱齿轮 helical gear single-helical gear 节点 pitch point节圆pitch circle齿顶圆 tip circle齿根圆 root circle直径和半径 diameter and radius齿宽 face width齿厚 tooth thickness压力角 pressure angle蜗杆 worm蜗轮 worm wheel联轴器 coupling刚性联轴器 rigid coupling万向联轴器 universal coupling齿 tooth齿槽 tooth space斜齿轮 helical gear齿距 pitch法向齿距 normal pitch轴向齿距 axial pitch齿高 tooth depth行星齿轮传动机构planetary gear drive mechanism 中心轮 center gear单级行星齿轮系 single planetary gear train刚度 rigidity扭转刚度 torsional rigidity弯曲刚度 flexural rigidity起动力矩 starting torque传动误差 transmission error传动精度 transmission accuracy固有频率 natural frequency弹性联接 elastic coupling刚性联接 rigid coupling周期振动 periodic vibration随机振动 random vibration峰值 peak value阻尼比 damping ratio减震器 vibration isolator振动频率 vibration frequency幅值 amplitude位移幅值displacement amplitude速度幅值 velocity amplitude加速度幅值 acceleration amplitude控制与监控系统远程监视 telemonitoring运输终端 remote terminal unit调制解调器 modulator-demodulator数据终端设备 data terminal equipment接口 interface数据电路 data circuit信息 information状态信息 state information监视信息 monitored information设备故障信息 equipment failure information 告警 alarm返回信息 return information确认 acknowledgement信号 signal模拟信号 analog signal命令 command字节 byte位bit地址 address编码 encode译码 decode代码 code控制台 control desk紧急停车按钮 emergency stop push-button限位开关 limit switch限速开关 limit speed switch指示灯 display lamp数据库data base硬件 hardware硬件平台 hardware platform层 layer level class模型 model响应时间 response time软件 software软件平台 software platform系统软件 system software一对一控制方式 one-to-one control mode一次电流 primary current一次电压 primary voltage二次电流 secondary current二次电压 secondary voltage低压电器 low voltage apparatus额定工作电压 rated operational voltage额定工作电流 rated operational current运行管理 operation management安全方案 safety concept外部条件 external conditions失效 failure故障 fault控制柜 control cabinet冗余技术 redundancy正常关机 normal shutdown失效-安全 fail-safe排除故障 clearance空转 idling外部动力源 external power supply锁定装置 locking device运行转速范围 operating rotational speed range临界转速 activation rotational speed最大转速 maximum rotational speed过载功率 over power临界功率activation power最大功率 maximum power短时切出风速 short-term cut-out wind speed外联机试验 field test with turbine试验台 test-bed台架试验 test on bed防雷系统 lighting protection system外部防雷系统 external lighting protection system 内部防雷系统 internal lighting protection system 等电位连接 equipotential bonding接闪器 air-termination system引下线 down-conductor接地装置 earth-termination system接地线 earth conductor接地体 earth electrode环形接地体 ring earth external基础接地体 foundation earth electrode等电位连接带 bonding bar等电位连接导体 bonding conductor保护等级 protection lever防雷区 lighting protection zone雷电流 lighting current电涌保护器 surge suppressor额定电流 rated current额定无功功率 rated reactive power停机 standstill起动 start-up切换运行 switching operation扰动强度 turbulence intensity电压变化系数 voltage change factor风力发电机端口 wind turbine terminals风力发电机最大功率 maximum power of wind turbine风力发电机停机 parked wind turbine 安全系统 safety system控制装置 control device额定载荷 rated load周期 period相位 phase频率 frequency谐波 harmonics瞬时值 instantaneous value同步 synchronism振荡oscillation共振 resonance波 wave辐射radiation衰减 attenuation阻尼 damping畸变 distortion电electricity电的 electric静电学 electrostatics电荷 electric charge电压降 voltage drop电流 electric current导电性 conductivity电压 voltage电磁感应 electromagnetic induction 励磁 excitation电阻率 resistivity导体 conductor半导体 semiconductor电路 electric circuit串联电路 series circuit电容 capacitance电感 inductance电阻 resistance电抗 reactance阻抗 impedance交流电压 alternating voltage交流电流 alternating current脉动电压 pulsating voltage脉动电流 pulsating current直流电压 direct voltage直流电流 direct current瞬时功率 instantaneous power有功功率 active power无功功率 reactive power有功电流 active current无功电流 reactive current功率因数 power factor中性点 neutral point相序 sequential order of the phase电气元件 electrical device电极 electrode地 earth接地电路 earthed circuit接地电阻 resistance of an earthed conductor 母线 busbar线圈 coil绕组 winding电阻器 resistor电感器 inductor电容器 capacitor继电器 relay电机 electric machine发电机 generator电动机 motor变压器 transformer变流器 converter变频器 frequency converter整流器 rectifier逆变器 inverter传感器 sensor耦合器 electric coupling放大器 amplifier振荡器oscillator滤波器 filter半导体器件 semiconductor触头 contact开关设备 switchgear控制设备 control gear闭合电路 closed circuit断开电路 open circuit通断 switching联结 connection串联 series connection并联 parallel connection星形联结 star connection三角形联结 delta connection主电路 main circuit辅助电路 auxiliary circuit控制电路 control circuit保护电路 protective circuit换向 commutation输入功率 input power输入 input输出 output负载load加载 to load充电 to charge放电 to discharge有载运行 on-load operation空载运行 no-load operation开路运行 open-circuit operation 短路运行 short-circuit operation 满载 full load效率 efficiency损耗 loss过电压 over-voltage过电流 over-current特性 characteristic绝缘物 insulant隔离 to isolate绝缘 insulation短路 short circuit噪声 noise极限值 limiting value额定值 rated value额定 rating环境条件 environment condition 使用条件 service condition工况 operating condition额定工况 rated condition加速 accelerating额定电压rated voltage额定电流 rated current额定频率rated frequency端电压 terminal voltage短路电流 short circuit current 可靠性 reliability有效性 availability耐久性 durability维修 maintenance维护 preventive maintenance工作时间 operating time待命时间 standby time修复时间 repair time寿命 life使用寿命 useful life平均寿命 mean life耐久性试验 endurance test寿命试验 life test加速试验 accelerated test安全性 fail safe应力 stress强度 strength试验数据 test data现场数据 field data电触头 electrical contact主触头 main contact击穿 breakdown耐电压 proof voltage放电 electrical discharge电线电缆 electric wire and cable电力电缆 power cable通信电缆 telecommunication cable油浸式变压器 oil-immersed type transformer干式变压器 dry-type transformer自耦变压器 auto-transformer有载调压变压器 transformer fitted with OLTC空载电流 non-load current阻抗电压 impedance voltage电抗电压 reactance voltage电阻电压 resistance voltage分接 tapping配电电器 distributing apparatus控制电器 control apparatus开关 switch熔断器 fuse断路器 circuit breaker控制器 controller接触器 contactor机械寿命 mechanical endurance电气寿命 electrical endurance旋转电机 electrical rotating machine直流电机 direct current machine交流电机 alternating current machine同步电机 synchronous machine异步电机 asynchronous machine感应电机 induction machine短路特性 short-circuit characteristic额定转矩 rated load torque规定的最初起动转矩 specifies breakaway torque交流电动机的最初起动电流 breakaway starting current if an a.c. 同步转速 synchronous speed转差率 slip同步系数 synchronous coefficient空载 no-load触电；电击 electric block正常状态 normal condition接触电压 touch voltage跨步电压 step voltage对地电压 voltage to earth中性点有效接地系统 system with effectively earthed neutral 过电压保护 over-voltage protection过电流保护 over-current protection断相保护 open-phase protection防尘 dust-protected过电流保护装置 over-current protective device保护继电器 protective relay接地开关 earthing switch漏电断路器 residual current circuit-breaker灭弧装置 arc-control device安全隔离变压器 safety isolating transformer避雷器 surge attester ; lightning arrester保护电容器 capacitor for voltage protection安全开关 safety switch限流电路 limited current circuit振动 vibration腐蚀 corrosion点腐蚀 spot corrosion金属腐蚀 corrosion of metals化学腐蚀 chemical corrosion贮存 storage贮存条件 storage condition运输条件 transportation condition空载最大加速度 maximum bare table acceletation挂钩 hook吊架 hanger振动试验 vibration tests老化试验 ageing tests冲击动载荷试验 impulse load tests耐腐试验 corrosion resistance tests安全帽 safety helmet安全带 safety belt绝缘手套 insulating glove绝缘靴 insulating boots护目镜 protection spectacles。
英语作文介绍常见能源现象
英语作文介绍常见能源现象Title: Common Energy Phenomena: An Overview。
Energy is an essential aspect of our universe, driving everything from the motion of celestial bodies to the functioning of our everyday gadgets. In this essay, we will delve into some common energy phenomena, shedding light on their significance and impact on our lives.1. Solar Energy:One of the most abundant sources of energy is sunlight. Solar energy is harnessed through various technologies like solar panels, which convert sunlight into electricity. This renewable energy source plays a crucial role in reducing our dependence on fossil fuels and mitigating climate change.2. Wind Power:Wind energy is another renewable resource generated by the movement of air masses on Earth. Wind turbines capture this kinetic energy and convert it into electrical power. Wind farms have become increasingly common in many regions, providing clean and sustainable electricity to communities.3. Hydroelectric Power:Hydroelectricity is produced by harnessing the energy of flowing water, typically by damming rivers to create reservoirs. As water flows through turbines, it generates electricity. Hydroelectric power plants are significant contributors to global electricity generation, offering a reliable and renewable energy source.4. Fossil Fuels:Despite their environmental drawbacks, fossil fuels remain the primary source of energy worldwide. Coal, oil, and natural gas are burned to produce heat and electricity, but their combustion releases harmful pollutants andgreenhouse gases, contributing to air pollution and climate change.5. Nuclear Energy:Nuclear power plants generate electricity through nuclear fission, where the nucleus of an atom is split to release energy. While nuclear energy is consideredrelatively clean in terms of greenhouse gas emissions, concerns about safety, radioactive waste disposal, and the risk of accidents persist.6. Geothermal Energy:Geothermal power taps into the Earth's internal heat to produce electricity and heat buildings. This renewable energy source is particularly abundant in regions with volcanic activity or geothermal reservoirs. Geothermal energy offers a reliable and sustainable alternative to traditional heating and cooling systems.7. Biomass Energy:Biomass energy is derived from organic materials such as wood, crop residues, and waste products. These materials are burned or converted into biofuels to produce heat, electricity, or transportation fuels. While biomass can be renewable, its sustainability depends on responsible harvesting practices and avoiding deforestation.8. Tidal Energy:Tidal power harnesses the energy of ocean tides to generate electricity. Tidal turbines placed in coastal areas capture the kinetic energy of moving water during the rise and fall of tides. Tidal energy holds great potential as a predictable and renewable source of power.9. Energy Efficiency:Beyond generating energy, improving efficiency in energy consumption is crucial for reducing waste and minimizing environmental impact. Energy-efficient technologies, such as LED lighting, smart thermostats, andenergy-efficient appliances, help conserve resources and lower energy bills.In conclusion, energy phenomena encompass a diverse range of sources and technologies that power our world. From renewable resources like solar and wind energy to traditional fossil fuels and emerging technologies like tidal power, understanding these phenomena is essential for shaping a sustainable energy future. By embracing cleaner and more efficient energy solutions, we can mitigate environmental challenges and ensure a brighter tomorrow for generations to come.。
水电站专业英语精简
一、英翻中1、At the end of 2011,cumulative global photovoltaic (PV) installation surpassed 69 GW,an increase of almost 70%,and PV power stations are commonplace in Germany,Italy,and Spain.2011年底全球的光电装机容量已超过690亿W,增长近70%,光电站在德国、意大利、西班牙十分普遍。
2、It can act as a transformer with inherent current limitation due to its lower coupling between the primary and the secondarywinding,which is unwanted in most other cases.由于在一次绕组和二次绕组之间有降低的耦合,这种变压器可做限流变压器用,这种功能在大多数其他情况下很少使用。
3、Extra voltage tappings are sometimes included,but to earn the name ‘isolating transformer it is expected that theywill usually be used at 1:1 ratio.有时也包括额外的电压抽头,但人们期望这种变压器的常用变比识1:1,故将其命名为“隔离变压器”。
4、The voltage used is appropriate for the shorter distance and varies from 2300V to about 35000V depending on utility standard practice,distance,and load to be served.他使用的电压适用于较短的距离,其变化为2300~35000V,电压值的大小取决于电力公司操作标准、传输的距离和负荷的大小。
风电企业监管汇报材料范文
风电企业监管汇报材料范文Wind power companies play a crucial role in the energy industry, providing sustainable and clean energy sources that help combat climate change. 风电企业在能源行业中发挥着至关重要的作用，提供可持续和清洁的能源来源，有助于应对气候变化。
As a regulatory body, it is essential to closely monitor the operations and performance of wind power companies to ensure compliance with industry standards and regulations. 作为监管机构，密切监测风电企业的运营和表现是至关重要的，以确保符合行业标准和法规。
One aspect of monitoring wind power companies involves reviewing their financial reports and budget plans to assess their financial health and sustainability. 监控风电企业的一个方面涉及审阅它们的财务报告和预算计划，以评估其财务健康和可持续性。
In addition to financial performance, regulatory bodies should also evaluate the environmental impact of wind power companies, including their efforts in wildlife protection and ecosystempreservation. 除了财务表现外，监管机构还应评估风电企业的环境影响，包括它们在野生动物保护和生态系统保护方面的努力。
风电场常用英语
风电常用英语单词汇总一、技术参数：风电场 wind farm wind power station风力机 wind turbine ['tɜːbaɪn; -ɪn]风力发电机组 wind turbine generator ['dʒenəreɪtə] system水平轴风力机 horizontal [hɒrɪ'zɒnt(ə)l] axis ['æksɪs] wind turbine 垂直轴风力机 vertical ['vɜːtɪk(ə)l] axis wind turbinerated ['reɪtɪd] power 额定功率rated wind speed 额定风速Cut-in wind speed 切入风速 cut-out wind speed 切出风速Survival [sə'vaɪv(ə)l] wind 最大风速/安全风速rotor['rəʊtə] diameter [daɪ'æmɪtə] 风轮直径Swept[swept] area 轮扫面积rotational [ro'teʃənl] direction [dəˈrekʃn] 旋转方向Tile [taɪl] 倾角 coning ['kəuniŋ] 锥角Rotational [ro'teʃənl] speed range 转速范围blade number 叶片数 Blade [bleɪd] length 叶片长度reactive [rɪ'æktɪv] power 无功功率upwind [ʌp'wɪnd]上风向 downwind [daʊn'wɪnd]下风向 gust[gʌst]阵风hub height [haɪt]轮毂高度power curve [kɜːv]功率曲线 blade material 叶片材料Glass-fiber reinforced resin 玻璃钢增强树脂Gearbox ['gɪəbɒks]齿轮箱One stage planet and two stage parallel axis cylindrical 一级行星两级平行轴齿轮brake [breɪk] system 刹车机构aerodynamic [,ɛrodaɪ'næmɪk] brake 气动刹车pitch [pɪtʃ] of blades 叶片变距mechanical [mɪ'kænɪk(ə)l] brake 机械刹车Disc brake 圆盘刹车 fail safe 失效安全性Yaw [jɔː] system 偏航系统 yaw control 偏航控制Active yawing 主动偏航 yaw drive 偏航驱动Drive motor ['məʊtə]驱动电机 yaw brake 偏航刹车Hydraulic [haɪ'drɔːlɪk; haɪ'drɒlɪk] disc brake 液压圆盘刹车Tower ['taʊə]塔筒nameplate ['neɪmpleɪt]名牌interior [ɪn'tɪɜːrɪə] diameter [daɪ'æmɪtə]内经outer ['aʊtə] diameter 外径二、风力发电机组机械部分：rotor blade 叶轮 Blade 叶片tip of blade 叶尖 Hub [hʌb]轮毂rotor ['rəʊtə] locking ['lɔkiŋ] device [dɪ'vaɪs]叶轮锁定装置pitch [pɪtʃ]桨距pitch controlled [kən'trəʊld]变桨距控制blade pitch system 变桨驱动系统 flange [flæn(d)ʒ]法兰main axle 主轴 hollow ['hɒləʊ] shaft [ʃɑːft]空心轴main [meɪn] bearing主轴承 extender 延长节gear 齿轮 gearbox ['gɪəbɒks]齿轮箱gear pair 齿轮副 train [treɪn] of gears 齿轮系gear pair with parallel ['pærəlel] axes 平行轴齿轮副planetary ['plænɪt(ə)rɪ] gear train 行星齿轮系pinion 小齿轮 wheel、gear 大齿轮driving gear 主动齿轮 driven gear从动齿轮gearbox ratio ['reɪʃɪəʊ]齿轮速比gear oil pump [pʌmp]齿轮油泵generator ['dʒenəreɪtə]发电机Doubly-Fed Induction['dʒenəreɪtə] Generator双馈风力发电机 (DFIG) generator ['dʒenəreɪtə] stator ['steɪtə]发电机定子generator rotor ['steɪtə]发电机转子hydraulic[haɪ'drɔːlɪk; haɪ'drɒlɪk] pressure ['preʃə] station 液压站hydraulic brake 液压刹车 hydraulic system motor 液压马达hydraulic distributor [dɪ'strɪbjʊtə]液压分配器Nacelle [nə'sel]机舱 Base frame [freɪm]机舱底座yaw system 偏航系统 yaw motor ['məʊtə]偏航电机yaw bearing ['beərɪŋ]偏航轴承 yaw brake 偏航刹车yaw pinion ['pɪnjən]偏航小齿轮yaw reducer [rɪ'djuːsə]偏航减速器cable twist [twɪst] counter ['kaʊntə]凸轮计数器hydraulic tubes for yaw brake 偏航油管base frame platform ['plætfɔːm]底座平台top box platform 顶舱柜平台Wind vane [veɪn]风向标 anemometer [,ænɪ'mɒmɪtə]风速仪tower 塔架 foundation [faʊn'deɪʃ(ə)n]基础foundation ring [rɪŋ]基础环 brake pad [pæd]刹车片brake disc [dɪsk] radius ['reɪdɪəs]刹车半径vortex generator 涡流发生器控制系统：control cabinet ['kæbɪnɪt]控制柜hermistor [θɜː'mɪstə]温度传感器transducer [trænz'djuːsə; ]转速传感器cooling system冷却系统electronic [ɪlek'trɒnɪk;] controller [kən'trəʊlə]电控console [kən'səʊl]控制台radiator ['reɪdɪeɪtə]散热器 inductor [ɪn'dʌktə]感应器shut down 关机 normal shut down 正常关机load [ləʊd]负载 to load 加载to charge [tʃɑːdʒ]充电 to discharge [dɪs'tʃɑːdʒ]放电on-load operation[ɒpə'reɪʃ(ə)n]有载运行 full load 满负荷no-load operation空载运行 commissioning [kə'miʃəniŋ]试运行short-circuit operation 短路运行open-circuit operation 开路运行三、机械常用：washer ['wɒʃə]垫圈 floor [flɔː] plate [pleɪt]平台thicken['θɪk(ə)n] gasket ['gæskɪt]加厚垫圈spring [sprɪŋ]弹簧 spring washer ['wɒʃə]弹簧垫圈O-ring seal [siːl] O型密封圈 leakage ['liːkɪdʒ]渗漏grease [griːs]润滑脂 grease pipe [paɪp]润滑油脂lubrication [,luːbrɪ'keɪʃən] pipe 润滑油管 oil pipe油管reinforcement [riːɪn'fɔːsm(ə)nt] tube 加强管entral ['sentr(ə)l] greasing ['sentr(ə)l] system 集中渗油单元tube [tjuːb] tie-in管接头spanner ['spænə]扳手 torque ['spænə] spanner 扭矩扳手socket ['sɒkɪt] spanner套筒扳手 nut [nʌt]螺钉screw [skruː]螺钉torque [tɔːk]扭矩crane [kreɪn]吊车cut the crane 摘钩 lifting tools [tuːlz]吊具 lifting ['liftiŋ]吊装hook [hʊk] bolt [bəʊlt]（eye bolt）吊耳、吊耳螺栓ladder ['lædə]梯子 bottom ['bɒtəm]底部corrosion [kə'rəʊʒ(ə)n] protection [prə'tekʃ(ə)n]防腐friction ['frɪkʃ(ə)n] value['væljuː]摩擦系数 arch [ɑːtʃ]弓形结构spiral ['spaɪr(ə)l]螺旋盘旋embedded [im'bedid]植入的内含的inspection [ɪn'spekʃn]检查视察accumulator [ə'kjuːmjʊleɪtə]储压罐against [ə'genst; ə'geɪnst] corrosion [kə'rəʊʒ(ə)n]抗蚀四、电力常用：grid [grɪd]电网 state grid 国家电网off-grid 离网 grid connected 并网voltage ['vəʊltɪdʒ; 'vɒltɪdʒ]电压current ['kʌr(ə)nt]电流alternating ['ɔːltəneɪtɪŋ] current 交流电DC circuit ['sɜːkɪt]直流电路three phase [feɪz] alternating ['ɔːltəneɪtɪŋ] current ['kʌr(ə)nt]三相交流电resistance [rɪ'zɪst(ə)ns]电阻 transformer [træns'fɔrmɚ]变压器conductor [kən'dʌktə]导体fuse[fjuːz]保险丝、熔丝circuit ['sɜːkɪt] breakers ['brekɚ]断路器frequency converter变频器 rectifier ['rektɪfaɪə]整流器cable lug ['kʌvə]电缆接头 cable splint ['kʌvə]电缆夹板cable ['keɪb(ə)l] cover ['kʌvə]电缆盖板rake [reɪk] for cable way 电缆槽connection [kəˈnekʃn] plate [pleɪt]连接板vibration [vaɪ'breɪʃ(ə)n] switch [swɪtʃ]振动开关nameplate['neɪmpleɪt]名牌polarity[pə(ʊ)'lærɪtɪ]极性parameter [pə'ræmɪtə]参数waterproofed['wɔːtəpruːf] pen 防水笔 rating ['reɪtɪŋ]级别capacitor [kə'pæsɪtə]电容 winding['waɪndɪŋ]绕组permanent-magnet 永久磁铁 terminal ['tɜːmɪn(ə)l]终端接线端compensation [kɒmpen'seɪʃ(ə)n] capacitor [kə'pæsɪtə]补偿电容lighting ['laɪtɪŋ]闪电 reverse[rɪ'vɜːs]相反、背面impedance [ɪm'piːd(ə)ns] voltage 阻抗电压power performance [pə'fɔːm(ə)ns]功率特性acoustic [ə'kuːstɪk] noise [nɒɪz]噪声earthing ['ə:θiŋ]接地 grid frequency ['friːkw(ə)nsɪ]电网频率speed up effect 加速 stall [stɔːl]失速star [stɑː] connection [kəˈnekʃn] 星型连接。
风电有功功率自动控制技术规范
风电有功功率自动控制技术规范Technical specificati on for automatic generation control of wind power2014-12-20发布2014-12-20实施目次前言 (II)1范围 (1)2规范性引用文件 (1)3术语和定义 (1)4总则 (3)5调度中心侧风电有功功率自动控制技术要求 (3)6风电场侧有功功率自动控制技术要求....................................................5 附录A (8)编制说明 (12)I前言为促进风电接入电网后的安全、优质、经济运行，规范国家电网范围内风电有功功率自动控制工作，提高风电利用率，特制订本标准。
本标准由国家电网公司国家电力调度控制中心提出并解释。
本标准由国家电网公司科技部归口。
本标准起草单位：国网吉林省电力有限公司，清华大学，中国电力科学研究院。
本标准主要起草人：郑太一，董存，孙勇，张小奇，杨国新，王彬，和青，范国英，范高锋，黄越辉，吴文传，李育发，张继国，李振元，李宝聚，曹政，王泽一。
本标准首次发布。
风电有功功率自动控制技术规范1范围本标准规定了风电有功功率自动控制的技术要求，包括控制模式、控制策略、功能要求及性能指标等。
本标准适用于含风电场接入的电网调度控制中心及通过110（66）kV 及以上电压等级线路接入电力系统的风电场。
2规范性引用文件下列文件对于本文件的应用是必不可少的。
凡是注日期的引用文件，仅所注日期的版本适用于本文件。
凡是不注日期的引用文件，其最新版本（包括所有的修改单）适用于本文件。
GB/T19963—2011风电场接入电力系统技术规定DL/T516—电力调度自动化系统运行管理规程DL/T634.5101—2002远动设备及系统第5101部分：传输规约基本远动任务配套标准（IE C60870-5-101:2002ID T）DL/T634.5104—2002远动设备及系统第5104部分：传输规约采用标准传输协议子集的IEC60870-5-104网络访问（IEC60870-5-104:2000IDT）国家电监会5号令电力二次系统安全防护规定Q/GDW1907—2013风电场调度运行信息交换规范Q/GDW680.35—2011智能电网调度技术支持系统第3-5部分：基础平台数据采集与交换Q/GDW680.42—2011智能电网调度技术支持系统第4-2部分：实时监控与预警类应用水电及新能源监测分析Q/GDW680.43—2011智能电网调度技术支持系统第4-3部分：实时监控与预警类应用电网自动控制3术语和定义下列术语和定义适用于本文件。
外文文献翻译
外文原文：Transmission Capacity of Grid-Connecting Channel for the Second Phase of 3 GW Jiuquan Wind Power Base Project and Configuration of Its Reactive Power Compensation Equipments1 INTRODUCTIONWind power is the most mature and economic benefit is one of the best renewable energy generation technology.Wind power has the characteristics of intermittent and randomness, volatility, which determine the big changes in the wind power output is likely to make the power system voltage stability and frequency stability..With the rapid development of wind power generation technology and the national policy on renewable energy power generation, wind power construction in China has entered a rapid development period.Wind resources in China is rich, but is suitable for large-scale development of wind power in the region are generally in the end of the grid, because the power grid structure is relatively weak, therefore may arise after the large-scale wind power connected to the electricity grid power grid voltage levels drop, line transmission power beyond thermal stability limit the system short circuit capacity increase and the system transient stability change such as a series of problems。
research findings雅思听力真题
research findings雅思听力真题Academic ReadingWind Power in the USPrompted by the oil crises of the s, a wind-power industry flourishedbriefly in the United States. But then world oil prices dropped, and fundingfor research into renewable energy was cut. By the mid s US interest in wind energy as a large-scale source of energy had almost disappeared. The development of wind power at this time suffered not only from badly designed equipment, but also from poor long-term planning, economic projections that were too optimistic and the difficulty of finding suitable locations for the wind turbines.Only now are technological advances beginning to offer hope that windpower will come to be accepted as a reliable and important source ofelectricity. There have been significant successes in California, inparticular, where wind farms now have a capacity of megawatts, comparable toa large nuclear or fossil-fuelled power station, and produce 1.5 per cent ofthe state’s electricity.Nevertheless, in the US, the image of wind power is still distorted byearly failures. One of the most persistent criticisms is that wind power isnot a significant energy resource. Researchers at the Battelle Northwest Laboratory, however, estimate that today wind turbine technology could supply 20 per cent of the electrical power the country needs. As a local resource, wind power has even greater potential. Minnesota’s energy commissioncalculates that a wind farm on one of the state’s south western ridges could supply almost all that state’s electricity. North Dakota alone has enoughsites suitable for wind farms to supply more than a third of all electricity consumed in the continental US.The prevailing notion that wind power is too costly results largely from early research which focused on turbines with huge blades that stood hundredsof metres tall. These machines were not designed for ease of production or maintenance, and they were enormously expensive. Because the major factors influencing the overall cost of wind power are the cost of the turbine and its supporting systems, including land, as well as operating and maintenance costs,it is hardly surprising that it was thought at the time that wind energy could not be supplied at a commercially competitive price.More recent developments such as those seen on California wind farms have dramatically changed the economic picture for wind energy. These systems, like installations in Hawaii and several European countries, have benefited from the economies of scale that come through standardised manufacturing and purchasing. The result has been a dramatic drop in capital costs: theinstalled cost of new wind turbines stood at $ per kilowatt in , down from about $ per kilowatt in , and continues to fall.Design improvements and more efficient maintenance programs for large numbers of turbines have reduced operating costs as well. The cost of electricity delivered by wind farm turbines has decreased from about 30 cents per kilowatt-hour to between 7 and 9 cents, which is generally less than the cost of electricity from conventional power stations. Reliability has also improved dramatically. The latest turbines run more than 95 per cent of the time, compared with around 60 per cent in the early s.Another misconception is that improved designs are needed to make wind power feasible. Out of the numerous wind turbine designs proposed or built by inventors or developers, the propeller-blade type, which is based on detailed analytical models as well as extensive experimental data, has emerged as predominant among the more than 20,000 machines now in commercial operation world-wide. Like the gas-driven turbines that power jet aircraft, these are sophisticated pieces of rotating machinery. They are already highly efficient, and there is no reason to believe that other configurations will produce major benefits.Like other ways of generating electricity, wind power does not leave the environment entirely unharmed. There are many potential problems, ranging from interference with telecommunications to impact on wildlife and natural habitats. But these effects must be balanced against those associated with other forms of electricity generation. Conventional power stations impose hidden costs on society, such as the control of air pollution, the management of nuclear waste and global warming.As wind power has been ignored in the US over the past few years, expertise and commercial exploitation in the field have shifted to Europe. The European Union spends 10 times as much as the US government on research and development of wind energy. It estimates that at least 10 per cent ofEurope’s electrical power could be supplied by land-based wind-turbines using current technology. Indeed, according to the American Wind Energy Association, an independent organisation based in Washington, Denmark, Britain, Spain and the Netherlands will each surpass the US in the generating capacity of wind turbines installed during the rest of the decade.Glossaryfossil fuel: coal, oil and natural gaskilowatt: 1,000 watts; a watt is a unit of powerkilowatt-hour: one kilowatt for a period of one hourmegawatt: one million wattswind farm: a group of wind turbines in one location producing a large amount of electricitywind turbine: a machine which produces energy when the wind turns its bladesQuestions 1 - 5Complete the summary below.Choose your answers from the box below the summary and write them in boxes 1-5 on your answer sheet.NB There are more words or phrases than you will need to fill the gaps.You may use any word or phrase more than once.ExampleThe failure during the late s and early s of an attempt toestablish a widespread wind power industry in the United States resulted largely from the ...(1) ... in oil prices during this period. The industry is now experiencing a steady ...(2)... due to improvements in technology and an increased awareness of the potential in the power of wind. The wind turbines that are now being made, based in part on the ...(3)... of wide-ranging research in Europe, are easier to manufacture and maintain than their predecessors. This has led wind-turbine makers to be able to standardise andthus minimise ...(4)... . There has been growing ...(5)... of the importance of wind power as an energy source.criticism successdesign costs production costsfailure stabilityoperating costs fallgrowth recognitionscepticism decisionseffects declineresultsQuestions 6 - 10Look at the following list of issues (Questions 6-10) and implications (A-C).Match each issue with one implication.Write the appropriate letters A-C in boxes 6-10 on your answer sheet.Example AnswerThe current price of one wind-generated kilowatt...A6. The recent installation of systems taking advantage of economies of scale ...7. The potential of meeting one fifth of current US energy requirements by wind power ...8. The level of acceptance of current wind turbine technology ...9. A comparison of costs between conventional and wind power sources ...10. The view of wind power in the European Union ...IMPLICATIONSA provides evidence against claims that electricity produced from wind power is relatively expensive.B supports claims that wind power is an important source of energy.C opposes the view that wind power technology requires further development.。
风电综述
A Comprehensive Overview on Reactive Power Compensation Technologies for Wind PowerApplicationsAhmed Faheem Zobaa1, and Milutin Jovanovic21Cairo University, Giza, Egypt2Northumbria University, Newcastle upon Tyne, United KingdomAbstract— The size and number of wind farms contributing to the energy production is continuously growing. The rating of wind turbines has increased from less than 1 MW a few years ago to 2- to 3-MW being installed today with 5-MW machines under development. The interaction of the wind farm, reactive power compensators, and the associated power network is being investigated. Because the loads and the wind farms' output fluctuate during the day, the use of reactive power compensation is ideal for the power system network. The purpose of this study is to provide wind farm developers and interested researchers with some valuable insights into the reactive power compensation techniques for wind farm power systems.I. I NTRODUCTIONind energy is a rapidly expanding industry.Global installed capacity has increased from 2,500 MW in 1992 to just over 40,000 MW at the end of 2004, at an annual growth rate of nearly 30%. Almost three quarters of this capacity has been installed in Europe. The European Wind Energy Association (EWEA) scenarios show that the future prospects of the global wind industry are promising and the total wind power installed worldwide could quadruple to 160,000 MW by 2012 [1,2]. For example, penetration levels in the electricity sector have reached 20% in Denmark. The German state of Schleswig-H olstein has 1,800 MW of installed wind capacity, enough to meet 30% of the region’s total electricity demand, while in Navarra (Spain), 50% of consumption is met by wind power.A reactive power compensator is a very important component of the wind generation system in the wind farms. Most of the wind turbines currently operating in the area are based on conventional cage induction generators (fixed speed, constant frequency ‘Danish’ concept) [1]. An induction generator requires reactive power to be supplied from the grid. It is therefore necessary to provide this power locally, and as close as possible to the demand levels. In the early days of wind farm development, the wind farm operators were supposed to compensate each wind turbine operated under no-load conditions. H owever, the induction generator requires an increasing amount of reactive power with load, and without proper compensation, the output voltage of the wind farm would oscillate with the wind speed variations. The aim of this paper is to review the reactive power compensation methods currently employed to tackle this and similar problems in wind farm power systems [1]-[18].II. O VERVIEWWind Energy Conversion Systems (WECS) are site specific and an intermittent source of power due to the nature of the wind velocity instantaneous and seasonal variations. This entails a high degree of precision in allocating a suitable site and sophistication in controlling the generated voltage and frequency produced by the WECS generating part.The WECS are used to either supply power to remote areas [3] or into the nearby distribution network (at the point of common coupling) incorporated as distributed generation ‘DG’ or bulk producing wind farms [4]. In order to supply power to remote areas as shown in Fig. 1, the generating system, operated in the so-called stand-alone mode, has to be equipped with its own ancillary units, such as voltage regulation and power factor correction devices and must also have sufficient storage capacity to meet the load demand, otherwise a second source of energy such as a diesel/alternator generating set need to be integrated in parallel with the system. On the other hand, grid-connected WECS use either inland or offshore large wind turbine ‘WT’ generators (10KW to 2MW units). The grid integrated WECS must meet the hosting utility integration requirements and adhere to the strict safety and protection regulations [5]. Once the integration is established, the WECS are considered to be a viable contribution and increase the utility’s reserve capacity. If the WECS are connected to the distribution network, grid integrated ancillary services are likely to be supplied by the hosting utility, which can impose stress, additional cost and pronounced network vulnerability to instabilities.The grid integrated WECS, as shown in Fig. 2, come in two categories; fixed speed and variable speed. The key advantages of variable speed WECS generators compared to their fixed-speed counterparts are the reduced mechanical stresses and higher conversion efficiency but at the expense of increased capital and maintenance cost [6]-[8]. The fixed speed WECS normally use a cage induction generator, coupled to theWwind turbine shaft through a fixed ratio gearbox, and therefore operate in a narrow range above the synchronous speed (so that the speed is virtually constant) with the wind turbine rotational speed being regulated by mechanical means (pitch control) at high winds. Variable speed WECS, however, allow the turbine to rotate at different rotational speeds ‘to match the maximum allowable wind velocity/power path’ thus maximizing the wind energy capture. The generator is usually a conventional induction generator with a gearbox, or a multi-pole wound rotor or permanent magnet synchronous generator directly coupled to the wind turbine rotor (the so called direct or gearless drive) [7,9]. In general, the generated voltage and frequency are electronically controlled using a bi-directional power converter connected either at the stator side (in this case, it must be fully-rated) or at the rotor side of a doubly-fed slip ring induction generator (DFIG) in a slip power recovery system where it can be partially-rated (due to limited speed ranges around the synchronous speed) with obvious cost reduction implications. Additional power factor correction capacitors are normally connected across the generator terminal once the load power factor is at low level.Voltage Electric DCloadFig. 1. Wind Energy Conversion System for off-grid applicationsP o in t o f C o m m o n P W M Fig. 2. Wind Energy Conversion System for grid integrationWind farms are arrays of WECS’s interconnected electrically so as to deliver cumulative power to the utility grid [10] as shown in Fig. 3. The electrical power output is considerably smoothed relative to that of a single turbine. The degree of smoothing depends on thegeographical extent of the wind farm, average wind speed, the control characteristics of the wind turbines and, finally, details of the terrain and how they influence the distribution of wind speeds across the wind farm. From an electrical power flow perspective, the wind farm acts in parallel with the utility's conventional generating capacity to supply the power demands of the connected load. Wind farms are made of tens to hundreds of turbines and have overall power rating of thousands to tens of megawatts. Usually, however, the power rating of a wind farm is but a small fraction of the conventional generation capacity on the grid, typically known as the wind penetration ratio. In general the ratio of wind generating capacity to the total system capacity (wind plus conventional sources) serving utility load at any given moment is measured by the wind penetration which currently does not exceeds 15% for most wind farms.To the distribution gridFig. 3. WECS grid integrated Wind FarmsIII. P ARALLEL C OMPENSATIONParallel compensation is a common practice in wind turbine generation systems and is used to increase the power factor of each turbine. Some wind turbines employ more than one value of the capacitor at their terminals to compensate reactive power at different wind speeds. The advantage of an improved power factor is the reduction of total current loading, which, in turn, reduces transmission loss and improves voltage regulation.Based on the equivalent circuit diagram in Fig. 4, the voltage and current equations in a vector form can be written as:E S = V S + n (R S + j X S ) I S (1) I S = I IM + I C (2)To keep the terminal voltage constant, it is necessary to adjust the amount of generated reactive power to follow the fluctuation in output power and to compensate for different number of turbines on-line.Fig. 4. Per-turbine, per–phase equivalent circuit of an induction machine (simplified) in a wind farm with n turbines Various sizes of capacitors or Static VAR Compensators (SVCs) can be used where the reactive power can be adjusted continuously at a different slip or power level. Ideally, a small-sized capacitor can be used during low wind speed to raise the voltage to an appropriate level, and a larger capacitor can be used in a high wind speed region to raise the voltage and the electromagnetic torque above the peak of aerodynamic torque.IV. S ERIES C OMPENSATIONFor series compensation, as the name implies, the capacitor is installed in series with the transmission line. The size of the capacitor is chosen to compensate for the line impedance, i.e., to reduce the effective reactance in the line impedance.The series capacitors are often used to improve the power transfer capability of transmission lines. Variable series capacitance is usually implemented by using thyristor control series (TCSC).Fig. 5 shows a per-phase, per-turbine equivalent circuit of a series-compensated system. Note that although the circuit is simplified, the actual calculations used to draw phasor diagrams are based on the complete circuit.The equations corresponding to the equivalent circuit in Fig.5 are:E S = V S + V Zs + V C (3)V Zs + V C = n (R S + j X S) I S- j n X C I S (4)Fig. 5. Series compensation of an induction machine (simplified) ina wind farm with n turbinesWith capacitor compensation, a small size of AC capacitor means a high reactance.Although the compensation improves the voltage conditions and the torque profile of the generator, there is an increase in the stator current in comparison to the uncompensated system for the same situation (300 turbines on-line). Parallel compensation improves the effective power factor of the wind farm seen from the PCC, thus reducing the transmission line current and the corresponding losses. Series compensation reduces the voltage drop across the transmission line, thus improving the electromagnetic torque of the induction generator.The effective power factor of the wind farm is not affected by series compensation. In a parallel compensation, the level of compensation decreases if the voltage across the capacitor decreases. On the other hand, in series compensation, the level of compensation increases with the increase of the line current. It is necessary to investigate the variation of terminal voltage at different slip and with different number of turbines on-line to determine the range of voltage on the PCC at different conditions.V. P ARALLEL A ND S ERIES C OMBINATION It is apparent that we can take advantage of both parallel and series compensation abilities of an AC capacitor. In a parallel compensation, the capacitor is used to compensate the individual induction generator, and for series compensation, to compensate the line impedance. Fig. 6 shows the per-phase equivalent circuitof a wind turbine connected to an infinite bus.Fig. 6. Series and parallel compensation of an induction machine(simplified)The equations for parallel and series combination can be written as:E S = V S + V Zs + V C (5)V Zs + V C = n (R S + j X S) I S - j n X C I S (6)I S = I IM + I C (7)VI. D YNAMIC C OMPENSATIONTwo kinds of dynamic compensation of reactive power will be highlighted below: SVC (Static Var Compensator) and SVC Light. The former is based on thyristor-controlled reactors and thyristor switched capacitors, whereas the latter is VSC (Voltage Source Converter) based.A Thyristor-Controlled Reactor (TCR) consists of a fixed reactor in series with a bi-directional thyristor valve. TCR reactors are by default of air core type, glassfiber insulated, and epoxy resin impregnated.A Thyristor-Switched Capacitor (TSC) consists of a capacitor bank in series with a bi-directional thyristor valve and a damping reactor, which also serves to de-tune the circuit to avoid parallel resonance with the network. The thyristor switch acts to connect or disconnect the capacitor bank for an integral number of half-cycles of the applied voltage. The TSC is not phase controlled, which means it does not generate any harmonic distortion. A complete SVC based on TCR and TSC may be designed in a variety of ways, to satisfy a number of criteria and requirements for its grid operation.SVC characteristics: Usually, the terminal voltage is allowed to vary in proportion with the compensating current, in accordance to a set slope. The SVC of TCR / TSC type is very useful as a means of dynamic voltage control in a number of situations such as mitigation of not too rapid voltage fluctuations and preventing voltage collapses in conjunction with grid faults as discussed above. Its dynamic response is limited by the maximum switching frequency of ordinary grid commutated power thyristors, i.e. 100 Hz.SVC control: The main objective of the control system is to determine the SVC susceptance needed at the point of connection to the power system, in order to keep the system voltage as close as possible to some desired value. This function is realised by measuring and comparing the system voltage with the set (reference) value. In case of a discrepancy between the measured and reference values, the controller makes sure that necessary changes are made in the susceptance until equilibrium is attained. The desired susceptance value is determined by the voltage regulator of the controller, and is achieved by generating appropriate firing signals for each thyristor. The overall active SVC susceptance is given by the sum of susceptances of the harmonic filters, the continuously controllable TCR, and the TSC if switched into operation. The control system also includes supervision of currents and voltages in different branches. If needed, protective actions are taken.Thyristor valves: The thyristor valves consist of single-phase assemblies. The thyristors are electrically fired. The energy for firing is taken from snubber circuits, also being part of the valve assembly. The order for firing the thyristors is communicated via optical light guides from the valve control unit located at ground potential. Between thyristors, heat sinks are located. The heat sinks are connected to a water piping system. The cooling media is a low conductivity mixture of water and glycol. The TCR and TSC valves each comprise a number of thyristors in series, to obtain the voltage blocking capability needed for the valves.Bi-Directional Control Thyristors:H igh power thyristors are normally able to conduct in one direction only, which is acceptable for most applications. In the SVC case, however, thyristors conducting in both directions of the current cycle would definitely offer possibilities for cost as well as space savings. In the most recent SVCs supplied, the thyristor valves are equipped with so-called Bi-Directional Control Thyristors (BCT). In such devices, two thyristors are actually integrated into one wafer with separate gate contacts. The two component thyristors of the BCT function completely independently of each other under static and dynamic operating conditions, and each of them has performance similar to a separate conventional device of the same current carrying capability. The valves comprise only one thyristor stack in each phase instead of two this resulting in a more compact design.SVC Light: With the advent of fully controllable semiconductor devices of high power rating, high performance voltage source converters have become feasible far into the tens of MVA range. With the SVC Light concept, the VSC (Voltage Source Converter) and IGBT (Insulated Gate Bipolar Transistor) technologies have been brought together to create a tool offering possibilities hitherto unseen for power quality improvement in industry and power distribution. This opens up completely new options for power quality control in areas so far unattainable or only partly manageable, such as active filtering and far-reaching mitigation of voltage flicker in sub transmission and distribution grids. The SVC Light technology is being implemented at present for flicker mitigation at a couple of different locations within European electric power industry.SVC Light is a flicker-mitigating device. It achieves this by tackling the root of the problem, the erratic flow of reactive power through the supply grid down into the loads. The reactive power consumption is measured, and corresponding amounts are generated in the SVC Light and injected into the system, thereby decreasing the net reactive power flow to an absolute minimum. As an immediate consequence, voltage flicker is decreased to a minimum, as well.Voltage Source Converters: The function of the VSC is to match the bus voltage in phase and frequency, and with amplitude, which can be continuously and rapidly controlled, so that it can be used as an effective tool for reactive power control.To this controlled reactive power branch, an offsetting capacitor bank is usually added in parallel, enabling the overall control range of the SVC Light to be capacitive. The reactive power supplied to the network is controlled at high rates by appropriately changing the switching pattern of the converter power devices. The response time is limited mainly by the switching frequency and the size of the reactor.The controllability of IGBTs also facilitates series connection of devices with safeguarded voltage sharing across each IGBT. This enables the SVC Light to be directly connected to voltages of tens of kV. Thanks to this, it becomes unnecessary to parallel converters in order to achieve the power ratings needed for wind power farms of the order of tens of MVA or larger.Pulse Width Modulation: The input of the Voltage Source Converter is connected to a capacitor, which is acting as a DC voltage source. At the output, the converter is creating a variable AC voltage by connecting the positive pole or the negative pole of the capacitor directly to any of the converter outputs. In converters thatutilize Pulse Width Modulation (PWM), the input DC voltage is normally kept constant and sinusoidal output voltage waveforms having only high switching harmonics are generated. The amplitude, frequency and phase of the fundamental output voltage is controlled by changing the switching pattern of the inverter legs.The VSC of the SVC Light has a switching frequency greater than 1 kHz. The voltage across the reactor at full reactive power is only a small fraction (typically 15%) of the output voltage. This makes the SVC Light nearly an ideal tool for fast reactive power compensation.IGBT: This power device has been chosen as the most appropriate for the SVC Light since it allows series connections owing to the low delay times for turn-on and turn-off. The IGBT has low switching losses and can thus be used at high switching frequencies. Nowadays, devices are available with both high power handling capability and high reliability, making them suitable for high power converters.As only a small power is needed for gate control of the IGBT, this can be taken from the main circuit. This is highly advantageous in high voltage converters, where many devices are connected in series. In addition, each IGBT module is equipped with an over-voltage monitoring system, which makes it possible to detect any operating abnormalities during the delivery test so that faulty devices could be replaced.The converter valve: The converter topology for the SVC Light is a three-level configuration. In such a converter the output of each phase can be connected to either the positive pole, the mid-point or the negative pole of the capacitor. The DC side of the converter is floating, or in other words, insulated relative to ground. Using the PWM, the converter will produce a very smooth phase current, with low harmonic content. The three-level topology also features low switching losses this implying high converter efficiency and high current capability.VII. C ONCLUSIONSCapacitor compensation can help boost the voltage at the PCC, thus improving the torque-speed capability of an individual induction generator.Ideal parallel compensation requires a variable reactive power as the output power and power factor fluctuate. A Static VAR Compensator can serve for this purpose.Series compensation can be used to offset the voltage drop across the line impedance. The capacitance value can be computed given the required compensation. TSCS can be considered to provide an adjustable series capacitor compensation.A combination of parallel and series compensation can improve the overall system. With a correct choice of capacitor sizes, fixed capacitors can be employed for both series and parallel compensation.Dynamic compensation of reactive power is an effective means of preserving power quality as well as voltage stability. It can be implemented by using thyristor-controlled reactors and thyristor-switched capacitors in parallel with the grid (SVC). An alternative is the voltage source converter (VSC) based shunt compensation. Here, the SVC Light combines VSC and IGBT technologies to attain high dynamic response, a prerequisite for effective flicker mitigation.R EFERENCES[1] European Wind Energy Association (EWEA), Press Release, London 23rd November 2004.[2] P. 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