SOLAR & WIND ENERGY.pptx power systems by Rgukt

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1. POWER SYSTEMS - I Prepared By Dr. M. Sriramulu Naik B.Tech , M.Tech , Ph.D. Assistant Professor in Dpt. of E.E.E . RGUKT-AP, Ongole Campus

2. STRUCTURE OF POWER SYSTEM

3. What is a Solar Cell? A solar cell (also known as a photovoltaic cell or PV cell) is defined as an electrical device that converts light energy into electrical energy through the photovoltaic effect . A solar cell is basically a p-n junction diode . Solar cells are a form of photoelectric cell, defined as a device whose electrical characteristics – such as current , voltage , or resistance – vary when exposed to light. Individual solar cells can be combined to form modules commonly known as solar panels. The common single junction silicon solar cell can produce a maximum open-circuit voltage of approximately 0.5 to 0.6 volts. By itself this isn’t much – but remember these solar cells are tiny. When combined into a large solar panel, considerable amounts of renewable energy can be generated.

4. Construction of Solar Cell A solar cell is basically a junction diode , although its construction it is little bit different from conventional p-n junction diodes. A very thin layer of p-type semiconductor is grown on a relatively thicker n-type semiconductor . We then apply a few finer electrodes on the top of the p-type semiconductor layer. These electrodes do not obstruct light to reach the thin p-type layer. Just below the p-type layer there is a p-n junction . We also provide a current collecting electrode at the bottom of the n-type layer. We encapsulate the entire assembly by thin glass to protect the solar cell from any mechanical shock.

5. Working Principle of Solar Cell When light reaches the p-n junction , the light photons can easily enter in the junction, through very thin p-type layer. The light energy, in the form of photons, supplies sufficient energy to the junction to create a number of electron-hole pairs. The incident light breaks the thermal equilibrium condition of the junction. The free electrons in the depletion region can quickly come to the n-type side of the junction.   Similarly, the holes in the depletion can quickly come to the p-type side of the junction. Once, the newly created free electrons come to the n-type side, cannot further cross the junction because of barrier potential of the junction. Similarly, the newly created holes once come to the p-type side cannot further cross the junction became of same barrier potential of the junction. As the concentration of electrons becomes higher in one side, i.e. n-type side of the junction and concentration of holes becomes more in another side, i.e. the p-type side of the junction, the p-n junction will behave like a small battery cell. A voltage is set up which is known as photo voltage. If we connect a small load across the junction, there will be a tiny current flowing through it.

6. V-I Characteristics of a Photovoltaic Cell

7. Materials Used in Solar Cell The materials which are used for this purpose must have band gap close to 1.5ev. Commonly used materials are- Silicon. GaAs . CdTe . Copper Indium Selenide - CuInSe 2 Criteria for Materials to be Used in Solar Cell Must have band gap from 1ev to 1.8ev. It must have high optical absorption. It must have high electrical conductivity. The raw material must be available in abundance and the cost of the material must be low.

8. Advantages of Solar Cell No pollution associated with it. It must last for a long time. No maintenance cost. Disadvantages of Solar Cell It has high cost of installation. It has low efficiency. During cloudy day, the energy cannot be produced and also at night we will not get  solar energy . Uses of Solar Generation Systems It may be used to charge batteries. Used in light meters. It is used to power calculators and wrist watches. It can be used in spacecraft to provide electrical energy.

9. Conclusion: Though solar cell has some disadvantage associated it, but the disadvantages are expected to overcome as the technology advances, since the technology is advancing, the cost of solar plates, as well as the installation cost, will decrease down so that everybody can effort to install the system. Furthermore, the government is laying much emphasis on the solar energy so after some years we may expect that every household and also every electrical system is powered by solar or the renewable energy source.

10. What is a Photovoltaic Cell? A photovoltaic cell is a type of  PN junction diode  which harnesses light energy into electricity. They generally work in a reverse bias condition. It is analogous to a solar cell since they belong to similar working principles but have distinct differences.

11. Construction of Photovoltaic Cell

12. The diagram above is a cross-section of a photovoltaic cell taken from a solar panel which is also a type of photovoltaic cell. The cell consists of each a P-type and an N-type material and a PN junction diode sandwiched in between. This layer is responsible for trapping solar energy which converts into  electricity . The N-type layer is also known as the first layer or the emitter layer. The P-type layer is the base layer and the intermediate layer between the two is the PN junction diode. The surface of the cell is covered by an anti-reflective material which traps the light energy and avoids any loss of energy. The bottom layer, the last one may completely be covered by the material in which the conductor is made up of.

13. Photovoltaic Cell Working Principle A photovoltaic cell works on the same principle as that of the diode, which is to allow the flow of  electric current  to flow in a single direction and resist the reversal of the same current, i.e , causing only forward bias current. When light is incident on the surface of a cell, it consists of photons which are absorbed by the semiconductor and electron-hole pairs are liberated to produce an external DC supply. In a solar cell, the junction area is much bigger than the photovoltaic cell because its main interest is the generation of power but for a photovoltaic cell the main purpose is the generation of electricity. If the incident energy ( hv ) is greater than the energy gap of that semiconductor material, these electron-hole pairs are generated at the depletion region of a diode. When this photon from external radiation hits the diode, these electron-hole pairs disrupt the neutrality of the conductor. If an external current path has been provided then the electrons flowing through the P-side travel towards the N- side,eventually generating a DC current and the magnitude of this electromotive force generated is directly proportional to the intensity of the incident radiation. This is the working of a photovoltaic cell.

14. Difference between Solar cell and Photovoltaic Cell Here is the difference between solar cell and photovoltaic cell in tabular format: property Solar Cell Photovoltaic Cell Definition A device that converts sunlight directly into electricity A device that converts light energy into electricity using the photovoltaic effect Source of Energy Sunlight Any light source (not necessarily sunlight) Applications Generate electric power from sunlight, solar calculators, solar panels Generate electric power from sunlight as well as artificial light, solar photovoltaic modules, building integrated photovoltaics Examples Silicon solar cell, Cadmium telluride solar cell, Perovskite solar cell Crystalline silicon photovoltaic cell, Thin film photovoltaic cell, Dye-sensitized solar cell

15. Advantages and Disadvantages of Photovoltaic Cell Following are the advantages and disadvantages of a photovoltaic cell. Advantages They generate clean energy and are sustainable for the environment Low maintenance costs. It is a  renewable energy source  and easily available. They have a lower risk for the loss of efficiency and can be used for a longer time period. Cancels  noise pollution . They can generate electricity anywhere as long as there is enough sunlight in a particular area. Can resolve our world’s energy crisis. Disadvantages The infrastructure for photovoltaic cells are not readily available on a larger scale. Though maintenance costs are low, the installation is much more expensive. Currently photovoltaic cells cannot produce electricity at a commercial level, they operate on devices which require less electricity and power. Long-range transmission is difficult when it comes to photovoltaics . They are fragile and can be easily damaged. Application of Photovoltaic Cell Some main applications of photovoltaic cells are as follows. Can be used in making solar farms, which would generate gigawatts of electricity. In difficult topographical conditions photovoltaic cells would efficiently deliver electricity than the conventional source. Can be used in standalone devices and meters. Primary power source for space explorations and experiments, due to its lightweight. Navigation aids.

16. Different Types of PV Cells Many new styles of PV cells are being developed today but mainly two distinct material: 1. Crystalline Silicon PV Cells ( Monocrystalline ) These Solar Cells are manufactured from  crystalline silicon . Many of you must be knowing that silicon is the second most common material on Earth and is abundantly found in sand. To make solar cells out of silicon, manufactured silicon crystals are sliced to about 300 micrometers thick and coated to work as a semiconductor to capture solar energy. 2. Thin-film or Polycrystalline PV Cells Thin-film PV cells use  amorphous silicon  or an alternative to silicon as a  semiconductor . These solar cells are relatively flexible and can be directly installed with building materials. They work great even during clouds when there is low sun light. Here, the disadvantage is that thin-film PV Cells comparatively generate less electricity than crystalline silicon cells.

17. Solar Photovoltaic Panels An array or Solar PV Cells are electrically connected together to form a PV Module and an Array of such Modules are again electrically connected together to form a Solar Panel. This connection is done by soldering using  flux cored solder wire  and  PV Ribbon . How much Electricity can a PV Cell Generate A single photovoltaic cell can produce about 1 to 2 watts of electricity. This energy is too less for use in any household or for a commercial purpose. In order to increase the output of electricity, several photovoltaic cells are electrically connected together to form a photovoltaic module and these modules are further electrically connected to form a photovoltaic panel / photovoltaic array. The number of modules connected to form an array depends on the amount of solar electrical energy needed. Converting DC to AC Electricity The PV cells generate DC or direct current. This DC electricity has to be converted to AC or alternating current so that it can be used in a  home lighting system  or running appliances. An inverter is used to convert DC to AC. This is same as converting DC from a battery to AC. Storing Electricity Generated by Solar Cells The electricity generated by solar cells by using solar energy has to be stored so that it can be used later as an when required. This is done by running the current into a bank of  Solar Batteries .  

18. What is Solar Power Plant? The solar power plant is also known as the Photovoltaic (PV) power plant. It is a large-scale PV plant designed to produce bulk electrical power from solar radiation. The solar power plant uses solar energy to produce electrical power. Therefore, it is a conventional power plant. Solar energy can be used directly to produce  electrical energy  using solar PV panels. Or there is another way to produce electrical energy that is concentrated solar energy. In this type of plant, the radiation energy of solar first converted into heat (thermal energy) and this heat is used to drive a conventional generator. This method is difficult and not efficient to produce electrical power on a large scale. Hence, to produce electrical power on a large scale, solar PV panels are used. In this article, we will explain details about solar PV plants and PV panel s. Below is the layout plan of photovoltaic power plant.

19. Photo Voltaic (PV) Principle Silicon is the most commonly used material in solar cells. Silicon is a semiconductor material. Several materials show photoelectric properties like; cadmium, gallium arsenide, etc. Electron-holes pairs are created in solar cells. The PV materials have the property to absorb photons of sunlight. The valance band electrons of semiconductor material are at lower energy and the electrons of conduction band are at a higher energy level. The difference between this energy level is known as bandgap energy E g . When sunlight falls on solar cells, the difference between photon energy E and bandgap energy E g  is absorbed by the cell. And it excites some electrons to jump across the bandgap . These electrons move from the valance band to the conduction band and create holes in the valance band. Therefore, if the potential difference exists within the cell, the electrons of the conduction band and holes of the valance band made the flow of  current  in the circuit.

20. According to Max Plant, the energy of photons is directly proportional to the frequency of radiation. Where, E P  = Energy of Photon h = Plank’s Constant = 6.62×10 -34  Js = 4.135×10 -15   eVs v = frequency of radiation (Hz) C = speed of light ≈ 3×10 8  m/s λ = Wavelength of radiation ( μm ) substituting these values in the above equation;

21. Components of Solar Power Plant The major components of the solar photovoltaic system are listed below. Photovoltaic (PV) panel Inverter Energy storage devices Charge controller System balancing component

22. Block diagram models of solar energy generation systems

23. Photovoltaic (PV) Panel PV panels or Photovoltaic panel is a most important component of a solar power plant. It is made up of small solar cells. This is a device that is used to convert solar photon energy into electrical energy. Generally, silicon is used as a semiconductor material in solar cells. The typical rating of silicon solar cells is 0.5 V and 6 Amp. And it is equivalent to 3 W power. The number of  cells is connected in series or parallel  and makes a module. The number of modules forms a solar panel. According to the capacity of power plants, a number of plates are mounted and a group of panels is also known as  Photovoltaic (PV) array . Inverter The output of the solar panel is in the form of DC. The most of load connected to the  power system  network is in the form of AC. Therefore, we need to convert DC output power into AC power. For that, an  inverter   is used in solar power plants. For a large-scaled grid-tied power plant, the inverter is connected with special protective devices. And a  transformer  is also connected with the inverter to assures the output voltage and frequency as per the standard supply.

24. Energy storage devices The batteries are used to store electrical energy generated by the solar power plants. The storage components are the most important component in a power plant to meet the demand and variation of the load. This component is used especially when the sunshine is not available for few days. The  capacity of a battery  is that how much amount of  electrical power  it can store. The  capacity of batteries is measured in Ampere-hours (AH) rating . For example, a battery having 100 AH battery can supply 1 Amp current for 100 hours or 100 Amp current for 1 hour. For a long  life of a battery , never fully discharge a battery. And in case, if a battery is fully discharged, never keep fully discharged battery for a long time. The capacity of a battery is affected by the temperature. There is a reduction of 0.6% of capacity for every degree Celsius rise in temperature more than 25˚ C. There are two  types of batteries  used in the solar power plant; Lead-Acid battery Nickel-Cadmium battery

25. Charge Controller A  charge controller  is used to control the charging and discharging of the battery. The charge controller is used to avoid the overcharging of the battery. The overcharging of a battery may lead to corrosion and reduce plate growth. And in the worst condition, it may damage the electrolyte of the battery. Sometimes, the charge controller is termed a solar battery charger. There are many technologies used to make a charge controller. For example, the most popular technique is the MPPT charge controller that is known as “Maximum Power Point Tracking”. This algorithm is used to optimize the production of PV cells. System balancing component It is a set of components used to control, protect and distribute power in the system. These devices ensure that the system working in proper condition and utilize energy in the proper direction. And it ensures maximum output and security of other components of a solar power plant.

26. Blocking diode The solar PV panels are connected with a battery. And these panels are used to charge the battery during sunlight is available. During charging of the battery, the current flows from panel to battery. But when the sunlight is not available, the current can be flow in a reverse direction and it may harm the solar panel. So, the  blocking diode  is a diode that is connected between the battery and panel to avoid reversal current from battery to panel. Voltage regulator The output of solar panels depends on sunlight. And the sunlight is not constantly available. It is continuously varying. Similarly, the output of the solar panel is also varying with respect to sunlight. This results in fluctuation in load current. The voltage regulators are used to maintain fluctuation within an acceptable range.

27. Performance of Solar Cell A solar cell is nothing but a  PN junction . The plot of short-circuit current (ISC) and open-circuit voltage (VOC) describes the performance of the solar cell. This plot is shown in the figure below. As shown in the above graph, Initially, the short-circuit current remains constant with an increase in  voltage . And a further increase in voltage results in a rapid decrease in current.

28. The power developed by the solar cell is calculated by multiplying current and voltage. And from that, we can draw a graph of power developed. As shown in the graph of developed power, at point P, the power is maximum. And we try to operate the panel at this point. This point is known as the maximum PowerPoint. And the algorithm used to track this point is known as maximum power point tracking (MPPT). The voltage at which the power is maximum is considered as maximum voltage ( V m ) and maximum current ( I m ). The factor which is used to describe the performance of the solar cell is known as the fill factor. The value of the fill factor remains between 0 to 1. Fill Factor  =  V m   I m  /  V OC  I SC   V m   I m  =  Fill Factor × V OC  I SC

29. The equivalent circuit of solar cells is as shown in the figure below. Where, I sc  = Source current generated by the sunlight I j  = Junction current I = Current passes through the load R L  = Load resistance

30. The relationship between current and voltage at the PN junction is given as the equation below. Where, I  = Saturation current V = Junction voltage e = electron charge = 1.602×10 -19  J/V k = Boltzmann’s constant = 1.381×10 -23  J/K T = Temperature (K)

31. Solar Cell Efficiency The efficiency of solar cells equates as below;   Factors affecting the efficiency of solar cells Theoretically,  solar cells  are used to operate at maximum efficiency. The main factors affecting the efficiency of solar cells are listed below. Temperature Sun Intensity Solar Shading Reflection

32. Temperature Due to the intrinsic characteristic of the semiconductor material, the efficiency of solar cells is highly impacted by temperature. The solar cells cannot operate efficiently at a higher temperature. And the efficiency of solar cells is high with lower temperatures. Sun Intensity The sun’s intensity varies throughout the day. In the afternoon, the sun intensity is maximum. During this time, the efficiency of solar cells is maximum. During evening and morning time, the sun intensity is not at peak level. Hence, during this time, the efficiency is lower compared to around afternoon time.

33. Solar Shading The efficiency of solar cells is highly dependent on solar shading. During a cloudy atmosphere, the solar cells are not capable to generate more energy. During the rainy season, the efficiency of solar cells decreases due to shading. Reflection The solar cell collects photon energy. But the efficiency of cells will decrease if the cells reflect light away from the surface. Untreated silicon surface reflects light up to 30% of incident light. To avoid this situation, an anti-reflection coating is used on the surface of the solar cells. Due to this coating, the solar cells appear dark blue or black.

34. Advantages and Disadvantages of Solar Power Plant Advantages The advantages of solar power plants are listed below. Solar energy is a clean and renewable source of energy which is an unexhausted source of energy. After installation, the solar power plant produces electrical energy at almost zero cost. The life of a solar plant is very high. The solar panels can work up to 25 years. This plant is not causing pollution. There are no moving parts in solar cells. So, maintenance is not needed to keep a solar plant running. It does not produce any noise. For a bulk generation, this plant can be installed in any land. So, there are no specific site selection criteria like thermal and hydropower plants. The solar plant can be installed on the house or flat. So, it reduces the transmission cost as it generates energy near the load center. In a grid-tied power plant, the electrical generate power can

35. Disadvantages The disadvantages of solar power plants are listed below. The initial cost of a solar panel is very high. It requires large land to produce electrical power in bulk amounts. The solar plant is only installed in countries where sun line is available efficiently. During a cloudy atmosphere, the solar plant cannot operate efficiently. The efficiency of a solar panel is very less. This plant generates electrical energy when sunlight is available. During the night, this plant cannot generate electrical power. Hence, if you need to use electrical power at night, you have to install a battery and charge controller. That increases the cost and maintenance of the plant as the life of a battery is very short. In a grid-tide power plant, the inverter is required, which is costly and needs skilled manpower and new technology to make sync with grid power quality.

36. Wind Power Plant Have you ever seen fans rotating by themselves due to the moving wind? This concept is called wind power as the flow of wind makes the blades of the turbines rotate. From this rotating kinetic energy, we can obtain mechanical energy. Further, this energy is converted into electrical energy. Wind power plants are the collection of all the wind turbines or windmills located in that area. These turbines are connected to a common station called the Wind power plant. Wind power plants, also known as wind farms, are facilities that use wind turbines to convert the kinetic energy of the wind into electrical energy. These plants are a source of renewable energy and help reduce greenhouse gas emissions.

37. Wind Power plants are a collection of wind turbines either horizontal or vertical type. These turbines collect the energy individually and are connected to a common plant. The wind turbine is also similar to the normal turbine, as it converts kinetic energy into mechanical energy. And they are designed in such a way that the height and length of the blades are maintained at some ratio. Among all the power plants Wind plant is one of the major plants with more than 20 years of life span. It usually requires maintenance every six months. The overall efficiency of a Wind turbine power plant is  20% - 40%. 

38. Working of Wind Power Plant So, how does a wind turbine work? The wind turbine works on the principle of conversion of  kinetic energy  of wind to mechanical energy used to rotate the blades of a fan connected to an electric generator. When the wind or air touches the blades (or) vanes of the windmill it the air pressure can be uneven, higher on one side of the blade and lower on the other. Hence, uneven pressure causes the blades to spin around the center of the turbine. The turbine does not operate at wind speeds above  55 mph  with the use of the controller. 

39. Fig : Working of wind power plant The rotor shaft of the turbine ( ie ., low speed and high speed) is interlinked with the gearbox which converts the  speed  from  30 to 60 rpm into 1000 to 1800 rpm . As the gearbox consists of  gears , to transmit mechanical energy. These speeds are most suitable to the generator for the generation of electricity. When the rotor of the turbine rotates it drives a generator through a setup gearbox causing the generator to produce electrical energy. Windmills are available in size from  100 KW to 36 MW  mainly used off-shore Now the engineers are designing  10 MW  of the wind turbine.

40. Types of Wind Power Plant (Wind Turbines) There are two types of wind turbines Horizontal Axis Wind Turbines (HAWT) Vertical Axis Wind Turbine (VAWT)

41. Horizontal Axis Wind Turbines (HAWT):   These turbines resemble windmills, with the tip of the shaft pointing in the direction of the wind. Smaller turbines are steered by wind vanes mounted on the building since they must face the wind. Wind sensors and servos are used with larger turbines to turn them.  Vertical Axis Wind Turbine (VAWT) Mounted on the vertical shaft is the main root. This gets rid of the problems with horizontal wind turbines. As they require more space and are difficult to install.

42. Wind Data and Energy Estimation : The wind velocity at any location varies continuously and the variation is irregular in terms of period and amplitude. Therefore, the duration (scale of the periods) is an important consideration in the design. The data based on the scale of the hour ( ie ., mean speed over a one-hour interval) is useful for the mechanical aspect of design. In addition to the data on the hourly mean velocity, the other information required is Spells of low wind speeds  - For providing storage or alternates Gusts for structural design-  To provide safety measurements against damage. Surface wind data on a national or regional basis is usually presented in the form of Isovents :  Contours of constant average wind velocity, in m/s. This data is presented in the form of a wind mop in which the mean annual velocity zones are marked Isodynes   Contours of constant wind power, in watts/m² This data is represented in the form of maps showing the available yearly average wind power. Energy estimation:  In a wind power plant the computing energy is the anticipated output of the facility based on variables including wind speed, air density, wind turbine efficiency, and turbine blade design. This estimation supports the losses caused by elements like friction and turbulence and accounts for the variation in wind speed over a year. The predicted energy output helps with project planning and funding decisions as well as predicting how well the wind power facility will perform. It can be estimated as follows,

43. About Power In The Wind Wind pressures energy under its motion. A portion of the energy can be extracted from the flowing mass of air and transformed into usable work by any mechanism that can slow it down, such as a sail or propeller. The following three variables affect a wind energy converter's output: The wind speed  The cross-section of wind swept by the rotor The overall conversion efficiency of the rotor, transmission system, and generator.  A well-designed wind turbine machine blades will exact 70% of the power available from wind energy  No device, however, well-designed can extract all of the wind's energy because the wind would have to be brought to a halt and this would prevent the passage of more air through the rotor. The most possible outcome is for the rotor to decelerate the whole horizontal column of intercepted air to about one-third of its free velocity. 

44. Therefore, the amount of wind energy that could be converted into mechanical energy by a 100% efficient aero generator would be limited to about 60%. A wind turbine's overall efficiency may drop to 35% or less due to losses in the gearbox, transmission system, generator, or pump, even though well-designed blades typically take 70% of the theoretical maximum. We know the wind machine will work on the principle of Converting the Kinetic energy of the wind to mechanical energy.

45. We know that Power is equal to energy per unit time Let D be the diameter of the turbine blades 

46. Force on the Blades of the Wind Power Plant The force acting on the blades of the wind machine are mainly two types, namely:  Circumferential Force that provides torque Axial Force acting in the direction of wind Circumferential Force  A circular construction, like a wind turbine blade, is subject to circumferential force, sometimes referred to as hoop stress. It happens as a result of the pressure difference between the blade's interior and exterior brought on by wind loads. The blade's aerodynamic performance may be compromised by the circumferential force, which could result in a loss of power and greater wear and tear on the turbine's parts.

47. Axial Force Acting in the Direction of Wind The force exerted on the wind turbine blades as the wind passes over them is referred to as the axial force acting in the direction of the wind. This force is inversely related to the wind's speed and the area that the blades are sweeping. Lift, which is a force perpendicular to the direction of the wind, and drag, which is a force parallel to the direction of the wind, are produced by the force acting on the blades. The rotation of the blades, which drives the generator and generates power, is a result of the lift and drag forces. The size of the axial force is determined by the wind turbine's design as well as the wind's characteristics, including wind speed and direction.

48. Site Selection For Wind Power Plant The following are the main factors to be considered for the selection of the site for installing windmills, The site selected should have the wind forms persists strongly at all times. The suitable wind speeds are between  7 m/sec and 30 m/sec. The site for windmills should be at a high altitude because the wind tends to have higher velocities at higher altitudes. Example : At 10 meters altitude the efficiency is  20-25 %  and at a  60-meter  altitude, its efficiency lies  30-60 %. The cost of the land should be low and the ground conditions at the site should be suitable for installation.  The site selected should be nearer to the users of generated electrical energy. The site selected should be free from environmental conditions such that the turbine blades should not be affected. The site selected should be nearer to the transport facilities such as road and railway

49. Block diagram models of wind energy generation systems

50. Components of Wind Power Plant Fig : Construction and Working of Windmill

51. Blades  are usually made of fiberglass or balsa wood. Most turbines have either two or three blades. Rotor : It includes the blades and the hub together. The blades spin the rotor, which is attached to a shaft that transfers the torque it creates into the gearbox. The rotor provides pitch regulation for power output optimization and control. Its speed is variable to maximize aerodynamic efficiency. Pitch  turns blades out of the wind to control the rotor speed and keep the rotor from turning in winds that are too high or too low to produce electricity. Brake  is a disc that can be applied aerodynamically, electrically, or hydraulically to stop the rotor in emergencies. A brake shuts down the turbine if the winds become strong enough to impact the turbine's internal components. Low-Speed Shaft: The rotor turns the low-speed shaft at about 15 to 30 rotations per minute. Gear box  connect the low-speed shaft to the high-speed shaft and increases the rotational speeds from about  15 to 30 rotations per minute (rpm)  to about  1000 to 1800 rpm,  the rotational speed required by most generators (alternators) to produce electricity. This is an expensive and heavy part of wind turbines.

52. Generator  is usually an induction generator that produces  50-cycle AC electricity.    Controller  starts up the machine at wind speeds of about  8 to 16 miles per hour (mph)  and shuts off the machine at about  55 mph.  Turbines do not operate at wind speeds above about  55 mph  because that might damage them. Anemometer : It measures the wind speed and transmits the data to the controller. The controller then corrects the turbine's direction, pitch, and yaw to best harvest the available wind energy. Wind vane  measures wind direction and communicates with the yaw drive to orient the turbine properly with respect to the wind. Nacelle  sits at the top of the tower and contains the gear box, low- and high-speed shafts generator, controller, and brake. It is essentially the cover for the machinery that translates wind power into electrical power. High-Speed Shaft:  Drives the generator Yaw drive   in upward turbines face into the wind. The yaw drive keeps the rotor facing into the wind as the wind direction changes. Downwind turbines don’t require a yaw drive, the wind blows the rotor downwind Yaw Motor powers the yaw drive Tower  is usually made from tubular steel, concrete, or steel lattice. Because wind speed increases with height, taller towers enable turbines to capture more energy and generate more electricity.

53. Wind Power Plant In India Being a renewable energy source Wind power plants have been established in many countries and in India as well. The following table shows the wind power plants in India at various locations and their generation capacity. Name Location Capacity (MW) Muppandal Wind farm Kanya Kumari 1500 Jaisalmer Wind farm Rajasthan 1604 Brahmanvel Wind farm Maharashtra 528 Anantapur wind park Andhra Pradesh 100 The first Wind power plant was set up in Ratnagiri , Maharashtra, Okha in Gujarat and Tuticorin in Tamil Nadu, in the year 1986. There are many Wind power plants in India but the largest wind power plant in India is in Tamil Nadu, with a 7455.2 MW capacity for the production of Wind Energy. Followed by Maharashtra with 4450.8 MW. 

54. Applications of Wind Power Plant They provide electricity for rural areas with limited grid connectivity. Wind power plants power industrial applications, reducing reliance on fossil fuels. They can be integrated with other renewable sources for hybrid energy systems. Wind power plants support off-grid installations and emergency power needs. They offer environmental benefits by reducing air pollution and preserving natural resources.

55. 10 Largest Wind Power Plants in India Here is a list of the 10 largest wind power plants in India along with some key information about each plant: Rank Wind Power Plant Capacity (MW) Location Year of Commissioning 1 Muppandal Wind Farm 1,500 Tamil Nadu 2005 2 Vankusawade Wind Park 1,000 Maharashtra 2012 3 Jaisalmer Wind Park 1,064 Rajasthan 2001 4 Dhule Wind Park 600 Maharashtra 2019 5 Lamba Wind Park 550 Gujarat 2011 6 Talasari Wind Park 400 Maharashtra 2015 7 Kayathar Wind Farm 330 Tamil Nadu 2015 8 Vayu Wind Park 310 Karnataka 2020 9 Kurnool Wind Farm 250 Andhra Pradesh 2017 10 Ratlam Wind Farm 250 Madhya Pradesh 2019

56. Top States In Installed Wind Power Capacity   Here is a list of the top states in India with the highest installed wind power capacity, along with some key information about each state: Rank State Installed Capacity (MW) 1 Tamil Nadu 9,674 2 Gujarat 7,462 3 Maharashtra 6,644 4 Rajasthan 5,558 5 Karnataka 4,801 6 Madhya Pradesh 3,746 7 Andhra Pradesh 3,472 8 Telangana 3,302 9 Kerala 1,473 10 Odisha 1,367

57. Advantages and Disadvantages of Wind Power Plant Till now we have discussed the concepts let's have a look over the Advantages and disadvantages of Wind power plants Advantages of Wind power Plant: Wind power is pollution free and it is a free source of energy  Suitable for small, remote domestic applications Cost of generation of power is cheap A successful strategy for supplying energy to rural places

58. Disadvantages of wind power plant: Wind power technology requires a higher investment than fossil-fueled generators  Wind is intermittent and it does not always blow when electricity is needed. Suitable areas of wind farms are often near the coast, where land is expensive Good wind sites are often located in remote locations, far away from cities where the electricity is needed. It can affect television reception if you live nearby Wind resource development may compete with other uses for the land and those alternative uses may be more highly valued than electricity generation There are some problems such as noise produced by the rotor blades, aesthetic (visual) impacts, and sometimes birds have been killed by flying into the rotors. It is liable to be affected by natural conditions such as weather and has large output variations.

59. Block Diagram of Hybrid PV-Wind generation unit