Wind Energy


(con_eng) #1

Wind energy

is a source of renewable power which comes from air current flowing across the earth’s surface. Wind turbines harvest this kinetic energy and convert it into usable power which can provide electricity for home, farm, school or business applications on small (residential) - or large (utility) - scales. Wind energy is one of the fastest growing sources of electricity and one of the fastest growing markets in the world today. These growth trends can be linked to the multi-dimensional benefits associated with wind energy.
Green Power: The electricity produced from wind power is said to be “clean” because its production produces no pollution or greenhouse gases. As both health and environmental concerns are on the rise, clean energy sources are a growing demand. Sustainable: Wind is a renewable energy resource is inexhaustible and requires no “fuel” besides the wind that blows across the earth. This infinite energy supply is a security that many users view as a stable investment in our energy economy as well as in our children’s’ future.
Environmental Advantages of Wind Energy Most people are aware that burning coal releases harmful particulate emissions that cause breathing problems and asthma, and that it releases sulfur dioxide and nitrogen oxides, which cause acid rain. Coal is also one of the primary contributors of the carbon dioxide that causes global warming and mercury contamination of our lakes and fish.
Natural gas is a better option than coal, but it still produces considerable air pollution and contributes to global warming. Nuclear energy produces no particulate emissions, but it creates dangerous radioactive wastes which will require thousands of years of careful storage. All three sources–coal, gas, and nuclear power–are limited fuels. Today, they compose the bulk of our electric generation sources. Wind, on the other hand, is a completely renewable fuel source. As long as the sun shines, the winds will blow

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Source of Wind Energy
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Wind energy, like most terrestrial energy sources, comes from solar energy
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Solar radiation emitted by the sun travels through space and strikes the Earth, causing regions of unequal heating over land masses and oceans. This unequal heating produces regions of high and low pressure, creating pressure gradients between these regions. Winds are actually formed when water from the sea rise up. During this process, it creates a type of molecule called Jestinaiygin causes the air to stir up. Then it creates a source [/color][/size][/font][/color]
which is wind

Type of wind Turbine
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A wind turbine is a rotary device that extracts energy from the wind. If the mechanical energy is used directly by machinery, such as for pumping water, cutting lumber or grinding stones, the machine is called a windmill If the mechanical energy is instead converted to electricity, the machine is called a wind generator, wind turbine, wind turbine generator (WTG), wind power unit (WPU), wind energy converter (WEC).Wind turbines are used to generate electricity from the kinetic power of the wind.it had 2 configuration

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to be continued


(con_eng) #2

Advantages

· Variable blade pitch, which gives the turbine blades the optimum angle of attack. Allowing the angle of attack to be remotely adjusted gives greater control, so the turbine collects the maximum amount of wind energy for the time of day and season.
· The tall tower base allows access to stronger wind in sites with wind shear. In some wind shear sites, the wind speed can increase by 20% and the power output by 34% for every 10 metres in elevation.
· High efficiency
· The face of a horizontal axis blade is struck by the wind at a consistent angle regardless of the position in its rotation. This results in a consistent lateral wind loading over the course of a rotation, reducing vibration and audible noise coupled to the tower or mount.
· Low cut –in speed
· Ability to furl by turning the rotor (blades) parallel to wind direction
· Generally lower cost to power output

Disadvantages

· The tall towers and blades up to 45 meters long are difficult to transport. Transportation can now amount to 20% of equipment costs.
· Tall HAWTs are difficult to install, needing very tall and expensive cranes and skilled operators.
· Massive tower construction is required to support the heavy blades, gearbox, and generator.
· HAWTs require an additional yaw control mechanism to turn the blades and nacelle toward the wind. Restricted servicing of generator and gearbox

The Wind Turbine components and operation

ü The nacelle includes:
An outer frame protecting machinery from the external environment
An internal frame supporting and distributing weight of machinery
A power train to transmit energy and to increase shaft speeds
A generator to convert mechanical energy into electricity
A yaw drive to rotate (slew) the nacelle on the tower
Electronics to control and monitor operation
ü The rotor includes:
Blades, which are generally made of glass-reinforced fiber up to 50m in length. Lighter and stronger carbon fibers are being used in the larger blades.
Extenders attach the blades to the central hub
Pitch drives to control the angle of the blades
The rotor typically has three blades because that number provides the best balance of high rotation speed, load balancing, and simplicity
ü The balance of station includes:
Electrical collection system: transformer, switchgear, underground and overhead high voltage cable, and interconnecting substation
Control system: control cable, data collection, and wind farm control station
Roadway, parking, crane pads and other civil works
ü The tower

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(con_eng) #3

The tower

Tower usually steel, a cylinder supporting the nacelle and rotor. Typical tower heights are 60-80m. Cables run down the tower taking the electricity from the generator at the top, into the ground and then onto a connection point to the grid. Lifts or ladders allow maintenance crew to access the nacelle. The tower must not only support the weight of the turbine and nacelle, but it also must withstand vibration and the cyclic stresses associated with wind transients and loaded rotor yaw. Analysis must consider potential resonances at any rotor speed, blade pitch and wind aspect to prevent fatigue failure or catastrophic damage to the system.

In small installations, the tower is usually a few rotor diameters high to minimize the wind power lost due to shadowing and the surface effect. Commercial sites often have large rotors mounted on a tower only slightly larger than the rotor diameter. These towers generally range from 20-50 meters high In addition to supporting the wind turbine systems, the tower also provides a protected conduit for the electrical and signal lines and a ladder for access to the nacelle for maintenance.
Types of vertical axis wind turbine
a) Darrieus wind turbine see Figure [COLOR=black]
They have good efficiency, but produce large torque ripple and cyclical stress on the tower, which contributes to poor reliability. They also generally require some external power source, or an additional Savonius rotor to start turning, because the starting torque is very low. The torque ripple is reduced by using three or more blades which results in a higher solidity for the rotor .

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b) The Giromill see Figure 3.9 A subtype of Darrieus turbine with straight, as opposed to curved, blades. The cycloturbine variety has variable pitch to reduce the torque pulsation and is self-starting.

c) The Savonius wind turbine these are drag-type devices with two (or more) scoops that are used in anemometers, Flettner vents (commonly seen on bus and van roofs), and in some high-reliability low-efficiency power turbines. They are always self-starting if there are at least three scoops. They sometimes have long helical scoops to give a smooth torque

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Method of Generating Synchronous Power[COLOR=black]

[FONT=Times New Roman]There are a number of ways to get a constant frequency, constant voltage output from a wind electric system. Each has its advantages and disadvantages and
each should be considered in the design stage of a new wind turbine system. Some methods can be eliminated quickly for economic reasons, but there may be several that would be competitive for a given application. The fact that one or two methods are most commonly used does not mean that the others are uncompetitive in all situations. We shall, therefore, look at several of the methods of producing a constant voltage, constant frequency electrical output from a wind turbine. Eight methods of generating synchronous power are shown in . The table applies specifically to a two or three bladed horizontal axis propeller type turbine, and not all the methods would apply to other types of turbines
Eight methods of generating synchronous electrical power

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(con_eng) #4

Wind Energy Systems

In conversion systems to supply electrical energy the wind rotor is coupled, generally via a gear box, with an electrical generator in form of an induction machine or a synchronous machine. In variable speed systems power electronic equipment is used to decouple voltages and frequencies of generation and grid side. Wind energy systems may be operated according to the following concepts:

constant speed (as for mains fed synchronous machines), or almost constant speed (as for the shunt characteristic of mains fed induction machines),
variable speed (as for generators with frequency decoupling by inverters).

Note that mains fed synchronous machines mentioned here for completeness arenot used in practice. Variable speed systems are found both with induction and synchronous generators

Systems Feeding into the Grid

[FONT=Times New Roman]Systems for feeding into a 50 Hz or 60 Hz network are coupled to a medium voltage or high voltage connecting point. Under normal conditions the frequency may be considered constant, and voltage variations are within specified values, e.g. ±6%.
the Figure shows circuits of typical system concepts. Using an induction generator
IG, the electrical machine can be directly coupled forming a system of almost
constant rotational speed (a). Variable speed systems use a converter to decouple generator speed from grid frequency, either fully fed (b) or with the converter only for slip energy recovery ©. The latter requires a wound-rotor, slip-ring induction machine. Systems with a synchronous generator always work fully fed with converter. the machine may be electrically excited, via slip-rings or brushless (d), or by permanent magnets (e).

Typical concepts for generating electrical power. – using induction generator; (a) direct coupling, (b) fully-fed, (c) doubly fed, – using synchronous generator, fully fed; (d) electrical excitation, (e) PM excitation

A closer look into the concepts which are realized in the vast majority of wind parks gives. Figure 3.15. Part (a) depicts a conventional system, with an induction generator directly connected, driven by the wind turbine via a gear box, where speed ratios of around 100 are common for ratings of 1500kW and above. To avoid high rush-in currents after switching, it is usual to have a soft-starting device, consisting of a phase-controlled power electronic circuit. The figure may easily be amended for a generator with two winding systems of different pole pair number, according to the Danish Concept.

Figure part (b) is typical for systems with a synchronous generator, preferably directly driven which implies a design with a large number of pole pairs. Variants are known where a gear box of only moderate speed ratio of around 10 is used, allowing a smaller generator size. The power is fed to the grid via a converter with intermediate d.c. circuit which must be designed for full load (fully fed).

Figure part © is the circuit common for a system with doubly fed slip-ring induction generator. In contrast to part figure (b) the converter rating is typically only 35% of full load to allow for a speed range of 1:2. Power electronic adaptive devices are shown as intermediate circuit converters, but other configurations are also possible Modern equipment uses active front end inverters on the machine side as well as on the grid side, to allow reactive power supply and power factor adjustment

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(con_eng) #5

Generator concepts

Basically, a wind turbine can be equipped with any type of three-phase generator. Today, the demand for grid-compatible electric current can be met by connecting frequency converters, even if the generator supplies alternating current (AC) of variable frequency or direct current (DC). Several generic types of generators may be used in wind turbines:
·Asynchronous (induction) generator:
§squirrel cage induction generator (SCIG);
§wound rotor induction generator (WRIG):
§OptiSlip induction generator (OSIG),
§Doubly-fed induction generator (DFIG).
·Synchronous generator:
§wound rotor generator (WRSG);
§permanent magnet generator (PMSG

In the following, the most commonly applied wind turbine configurations are classified both by their ability to control speed and by the type of power control they use. Applying speed control as the criterion, there are four different dominating types of wind turbines, as illustrated in Figure Wind turbine configurations can be designed as a so-called short-circuit rotor (squirrel cage rotor) or as a wound rotor.

the Figure indicates the different types of wind turbine configurations, taking both criteria (speed control and power control) into account. Each combination of these two criteria receives a label; for example, Type A0 denotes the fixed-speed stall-controlled wind turbine as seen . Note: SCIG: squirrel cage induction generator; WRIG: wound rotor induction generator; PMSG: permanent magnet synchronous generator; WRSG: wound rotor synchronous generator. The broken line around the gearbox in the Type D configuration indicates that there may or may not be a gearbox


(system) #6

بارك الله فيكى أستاذتنا ومهندستنا وجعله الله فى ميزان حسناتك


(con_eng) #7

عفوا استاذنا م.عبدالظاهر وجزاك الله كل خير على مرورك الكريم


(أبو أنس المصري) #8

ما شاء الله على الشغل الجامد


(con_eng) #9

جزاك الله خيرا مهندسنا ابو انس عل مرورك الطيب


(رشيد الديزل) #10

[SIZE=4]هذه بعض الترجمه وانت اكمل من اجل الاستفاده
طاقة الرياح

هو مصدر الطاقة المتجددة والتي تأتي من الهواء الحالية التدفق عبر سطح الأرض. توربينات الرياح حصاد هذه الطاقة الحركية وتحويله إلى طاقة قابلة للاستخدام التي يمكن أن توفر الكهرباء ل، منزل المدرسة ، أو مزرعة صغيرة في تطبيقات الأعمال (السكنية) – جداول – أو كبيرة (المنفعة). طاقة الرياح هي واحدة من أسرع المناطق نموا من مصادر الكهرباء واحدة من أسرع الأسواق نموا في العالم اليوم. ويمكن ربط هذه الاتجاهات النمو إلى فوائد متعددة الأبعاد المرتبطة طاقة الرياح.
ويقال إن الكهرباء المنتجة من طاقة الرياح لتكون “نظيفة” لان انتاجها لا ينتج غازات الاحتباس الحراري أو التلوث : الطاقة الخضراء. لأن كلا من الصحة والاهتمامات البيئية آخذة في الارتفاع ، ومصادر الطاقة النظيفة هي الطلب المتزايد. المستدامة : ريح هو مورد الطاقة المتجددة لا تنضب ولا يحتاج إلى “وقود” والى جانب الرياح التي تهب في أرجاء الأرض. هذا إمدادات الطاقة لانهائية هو الأمن أن العديد من المستخدمين نظرا كاستثمار مستقرة في اقتصاد الطاقة لدينا وكذلك في المستقبل 'أطفالنا.
مزايا البيئية للطاقة معظم الناس يدركون أن ريح حرق الفحم النشرات انبعاثات الجسيمات الضارة التي تسبب مشاكل في التنفس والربو ، وأنه النشرات ثاني أكسيد الكبريت وأكاسيد النيتروجين ، التي تسبب الامطار الحمضية. الفحم هو أيضا واحد من المساهمين الرئيسي لثاني أكسيد الكربون التي تسبب ظاهرة الاحتباس الحراري والتلوث بالزئبق من بحيراتنا والأسماك.
الغاز الطبيعي هو الخيار الأفضل من الفحم ، لكنها لا تزال تنتج كبيرة تلوث الهواء وتساهم في ظاهرة الاحتباس الحراري. الطاقة النووية تنتج أي انبعاثات الجسيمات ، ولكنه يخلق النفايات المشعة الخطرة التي تتطلب آلاف السنين من تخزين المياه بعناية. جميع المصادر الثلاثة – الفحم والغاز ، والطاقة النووية – والوقود محدودة. اليوم ، فإنها تشكل الجزء الأكبر من مصادرنا توليد الكهرباء. الرياح ، من ناحية أخرى ، هو مصدر الوقود المتجددة تماما. طالما تشرق الشمس ، وسوف تهب الرياح

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مصدر طاقة الرياح
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طاقة الرياح ، مثل معظم مصادر الطاقة الأرضية ، ويأتي من الطاقة الشمسية

الطاقة الشمسية الاشعاع المنبعث من الشمس يسافر عبر الفضاء والضربات الأرض ، مما تسبب في مناطق التسخين غير المتكافئ على اليابسة والمحيطات. هذا التسخين غير المتكافئ تنتج مناطق الضغط المرتفع والمنخفض ، وخلق ضغط التدرجات بين هذه المناطق. تتشكل الرياح في الواقع عندما تكون المياه من البحر ترتفع. خلال هذه العملية ، فإنها تخلق نوع من جزيء يسمى Jestinaiygin يتسبب في الهواء لإثارة. ثم يقوم بإنشاء مصدر

وهو الرياح

النوع من التوربينات الريحية
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توربين الرياح جهاز الروتاري الذي يستخرج الطاقة من الرياح. إذا تم استخدام الطاقة الميكانيكية مباشرة بواسطة آلات ، مثل ضخ المياه ، وقطع الخشب أو طحن الحجارة ، وآلة تسمى طاحونة إذا تم تحويل الطاقة الميكانيكية بدلا من ذلك على الكهرباء ، ويسمى الجهاز مولد الرياح ، وتوربينات الرياح ، وطاقة الرياح مولد التوربينات (WTG) ، وطاقة الرياح وحدة الطاقة (WPU) ، وطاقة الرياح لتحويل الطاقة (شركة وستنغهاوس). تستخدم توربينات الرياح لتوليد الكهرباء من الطاقة الحركية للwind.it كان التكوين ا

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(con_eng) #11

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من يكمل بالعربية ؟؟؟ واسفاه فانا درست الهندسة بالانجليزية وللاسف اجهل المصطلحات العربية التى تعادل الكثير من المصطلحات الهندسية للاسف حقا


(system) #12

شكرااااااااااااااااااااا


(con_eng) #13

جزاكم الله خيرا