Project-Solar-based light intensity controller using "PWM". Implemented Home Automation System Project Which is Based on Renewable Energy use.

1. A
SEMINAR REPORT
ON
Over view of Multi-Mega Watt Wind
Turbines
Submitted in partial fulfillment of the requirements for the degree of
Bachelor of Technology
By
ANUPAM B. SHRIVASTAVA
U14EE021
: Supervisor:
Manisha Gohil
DEPARTMENT OF ELECTRICAL ENGINEERING
SARDAR VALLABHBHAI NATIONAL INSTITUTE OF TECHNOLOGY
SURAT – 395007
November-2017

2. SARDAR VALLABHBHAI NATIONAL INSTITUTE OF TECHNOLOGY
SURAT-395 007, GUJARAT, INDIA
DEPARTMENT OF ELECTRICAL ENGINEERING
SVNIT
CERTIFICATE
This is to certify that the seminar report titled “Overview of Multi-Mega Watt
Wind Turbines ” submitted by Anupam B. Shrivastava, U14EE021 is a record of
bonafide work carried out by him in partial fulfillment of the requirement for the
award of the degree of “Bachelor of Technology IN ELECTRICAL
ENGINEERING”.
Date:16-11-2017
Place: SVNIT, Surat
(Faculty Supervisor)
Examiners
Head of Department

3. i
ACKNOWLEDGMENT
I would like to express my deep sense of gratitude to my guide Shri
Janak Patel Sir (Associate Professor, EED, SVNIT, SURAT) for his valuable
guidance, motivation and for his extreme cooperation to complete this report.
I would like to express my sincere respect and profound gratitude to Dr.
S. N. Sharma Sir, Head of Electrical Engineering Department for supporting
and providing the facilities for my seminar work.
I appreciate all my colleagues whose direct and indirect contribution helped
me a lot to accomplish this report. I would like to thank all the teaching and
non-teaching staffs for cooperating with me and providing valuable advice
which helped me in the completion of this work.
I would like to express my thanks to all the members of my lovely family,
without whose support I would have never been able to aspire for this level of
education.
- Anupam B. Shrivastava
-U14EE021

4. ii
ABSTRACT:-
In today’s world most of our major industries and hence economy depends on a
reliable source of electricity. Thus it becomes imperative that the network of
generators, motors that should be used and with reliable technology. Thus it
becomes necessary to understand the machines and the generation of wind
turbines.
This paper deals with wind power generation and the generators that used in
generation. Of all the renewable energy sources; the one that has matured to the
level of being a utility generation source is wind energy .It is estimated that wind
potential is 1.6*10 7
MW which is same as world energy requirement. So we
mainly concentrate on the generators used during generation and how they are
different from each other. The different types of generators fundamentals of wind
energy and generators used for this technology, wind turbines, types of wind
turbines horizontal axis design & vertical axis design, generators and motors ,
types of generators and motors used: • induction motors • permanent magnet
synchronous generators.Using modern power electronics and special type of wind
turbines that suit to the conditions.

5. iii
TABLE OF CONTENTS:-
1. Acknowledgement……………………………………………………………...(i)
2. Abstract………………………………………………………………………...(ii)
3. Table of Figures……………………………………………………………….(iv)
4. Chapter 1:-Introduction:-………………………………………………………(1)
1.1 Advantages of Wind Energy Over Other Non Conventional Sources……(2)
1.2 Statistics…………………………………………………………………..(3)
5. Chapter 2:-Origin Of Wind:-………………………………………………….(6)
2.1 Generation Of Power From Wind……………………………………......(7)
2.2 Fundamentals Of Wind Energy & Generators Used for this Technology.
2.3 Power Flow……………………………………………………………….(8)
2.4 Wind Turbine Generation System……………………………………......(9)
6. Chapter 3:-Wind Turbine:-…………………………………………………...(11)
3.1 WECS Technology……………………………………………………...(13)
3.2 Generation System………………………………………………………(15)
3.3 Types Of Generators:-…………………………………………………...(16)
a.Squirrel Cage Induction Generators.
b.Doubly Fed Induction Generators…………………………………..(18)
c.Direct Drive Synchronus Generators……………………………….(21)
7.Conclusion………………………………………………………………….....(22)
8.References……………………………………………………………………..(23)

6. iv
Index Of Figures:-
1. Statistical data of global cumulative wind capacity……………………….Fig.1.1
2. Statistical data of india’s wind energy installation………………………...Fig.1.2
3. Generation of power from wind…………………………………………...Fig.1.3
4. Wind turbines and parts…………………………..………………………..Fig.1.4
5. Metallic bars……………………………………………………………….Fig.1.5
6. How does a wind turbine work?...................................................................Fig.1.6
7. Gear box…………………………………………………………………...Fig.1.7
8. Horizontal axis wind turbine…………………………………………….Fig.1.8
9. Squirrel cage induction generator……………………………………….Fig.1.9
10. Doubly cage fed induction generator.……………………………………Fig.2.0
11. Converters……………………………………………………………...Fig.2.1
12. Direct drive synchronous generator...………………………………….Fig.2.2

7. 1
Chapter 1
Introduction
While fossils fuels will be the main fuels for the thermal power there is a
fear that they will get exhausted eventually in next century therefore many
countries are trying systems based on non-conventional and renewable sources.
These are Solar, Wind, Sea, Geothermal and Biomass. Because if we take solar
power on earth it is 10 6
watts.The total world demand is 10 13
watts, If we utilize
5% of the solar energy, it will be 50 times what that world require. If we consider
the wind potential it is estimated to 1.6*10 7
M.W, which is same as world energy
consumption. So the development of non-conventional energy source is very;
economical.[1]
 WHY WIND ENERGY:-
The majority of electricity is generated by burning coal, rather than more eco-
friendly methods like hydroelectric power. This use of coal causes untold
environmental damage through CO2 and other toxic emissions.
The energy sector is by far the biggest source of these emissions, both in the India
and globally, and if we are to tackle climate change it is clear we need to move
away from burning limited fossil fuel reserves to more sustainable and renewable
sources of energy.

8. 2
ADVANTAGES OF WIND ENERGY OVER OTHER
NON-CONVENTIONAL SOURCES:-
 It is available through out the day unlike solar energy.
 After solar energy it is the second largest source of non-conventional source of
energy.
 BENEFITS OF WIND POWER:-
Wind power has many advantages that make it a lucrative source of power for both
utility scale and small, distributed power generation applications. The beneficial
characteristics of wind power include:-
 Clean and endless fuel—Wind power doesn‘t produce any emissions and is not
run down with time. A one megawatt (1 MW) wind turbine for one year can
displace over 1,500 tons of carbon dioxide, 6.5 tons of sulphur dioxides, 3.2
tons of nitrogen oxide, and 60 pounds of mercury (based on the U.S. average
utility generation fuel mix).
 Local financial development—Wind plants can provide a firm flow of income
to landowners who lease their land for wind development, while increasing
property tax revenues for local communities.

9. 3
 Modular and scalable technology—Wind applications can take many forms,
including large wind farms, distributed generation, and single end-use systems.
Utilities can use wind resources tactically to help reduce load forecasting risks
and trapped costs.
 Energy price stability—by further diversifying the energy mixture, wind
energy reduces dependence on conventional fuels that are subject to price and
supply instability.
 Reduced dependence on imported fuels—Wind energy expenditures don‘t need
to obtain fuels from abroad, keeping funds closer to home, and lessening
reliance on foreign governments that supply these fuels.[1]
 FACTS OF WIND POWER:-
• World's Largest Turbine generates about 6MW power.
• Wind is Uncontrollable => Special generators are needed & SUZLON group
of U.S is biggest manufacturer.
• Suzlon Group recently announced that its Jaisalmer wind farm, the largest in
India, crossed 1,000 MW (or 1 GW) of capacity.

10. 4
STATISTICS:-
With the fast growing demand for power and an emphasis on clean energy, India
has also taken its step forward along with other countries. According to the Global
Wind Report 2016, the total installed wind capacity at the end of 2016 is just shy
of 238 GW. Out of the total capacity India installed wind power generation
capacity stood at about 16085MW constitute 6.8% of global wind power capacity.

11. 5
 WIND ENERGY – INDIAN SCENARIO:-
In the early 1980s, the government of India established the Ministry of Non-
Conventional Energy Sources (MNES) to promote diversification of the country's
energy supply and satisfy the ever-increasing energy demand of its rapidly growing
economy. In 2006, this ministry was renamed as the Ministry of New and
Renewable Energy (MNRE).
During the first decade of the 21st century, India emerged as the 2nd leading wind
power market in Asia. Currently, its cumulative installed capacity is close to 13
GW, with the market growing at an average rate of over 20% over the past 3 years.
More than 2,100 MW wind capacity projects were added in the financial year
2010–11. The installed capacity increased from a modest base of 41.3 MW in 1992
to reach 13,065.78 MW by December 2010.[3]

12. 6
Chapter 2
Origin Of Wind:-
The earth is formed of highly varied surfaces and when solar radiations reach the
earth, it creates temperature, density and pressure differences. This causes the
development of the wind.
GENERATION OF POWER FROM WIND:-
The working principle of a wind turbine encompasses two conversion processes,
which are carried out by its components, the rotor that extracts kinetic energy from
the wind and converts it into a generator torque and the generator that converts this
torque into electric power and feeds it into the grid.
Fig.1.3-Generation of power from wind
Rotor
Generator
Grid
Mechanical
power
(translation)
Mechanical
power
(rotation)
Electrical
power

13. 7
Wind turbines produce electricity by using the power of the wind to drive an
electrical generator. Passing over the blades, wind generates lift and exerts a
turning force. The rotating blades turn a shaft inside the nacelle, which goes into a
gearbox. The gearbox adjusts the rotational speed to that which is appropriate for
the generator, which uses magnetic fields to convert the rotational energy into
electrical energy. The power output goes to a transformer, which converts the
electricity from the generator at around 700V to the appropriate voltage for the
power collection system, typically 33 kV.[Google]
Fundamentals Of Wind Energy and Generators Used for
this Technology:-
 WIND POWER:-
 Harnessed by using wind flow as the driving force of the generator in order to
create a torque on the rotor and in effect produce electricity.
 World's Largest Turbine generates about 6MW power.
 Wind is Uncontrollable => Special generators are needed.
 For constant rotor speed: some wind turbines have motors/controllers that drive
the blades when the wind is not strong enough.
 Wind power is the conversion of wind energy into a suitable form of energy,
such as using wind turbines to generate electricity, windmills for mechanical
power, wind pumps for water pumping, or sails to propel ships.

14. 8
 WIND TURBINES & PARTS :-Fig.1.4

15. 9
 GENERATORS & METALLIC BARS:-
 Types of generators and metallic bars used:-
1.Induction Generators
2.Permanent Magnet Synchronous Generators
Fig.1.5-Metallic bars
1.Circular metallic bar
2.Spring type metallic bar

16. 10
 EQUATIONS & PARAMETERS:-
 Power Flow:-
Pin 3 VL IL cos  3 Vph Iph cos
Pscl  3 I 1
2
R1
Pag Pin

(
Pscl



Pcore

)
Prcl  3 I 2
2
R2
Pconv PagPrcl
Pout Pconv
Pfw
Pstray)

17. 11
Chapter 3
Wind turbine:-
The wind turbine is playing a cardinal role in the entire system as it is responsible
for the generation of mechanical power needed to drive the generator.
The primary factors on which the wind turbine performance depend are:-
 Wind speed:-TIP SPEED RATIO
 Direction of wind
 Blade size:-SPECIFIED RATED CAPACITY
 Mechanical gears involved in its design:-GEAR BOX
Fig.1.6-How does a wind turbine work?

18. 12
 TIP SPEED RATIO:-
Tip speed ratio of a wind turbine (λ) is defined as:
Where ω is rotational speed of rotor (in rpm), R is the radius of the swept area (in
meter).The tip speed ratio λ and the power coefficient Cp are the dimensionless
and so can be used to describe the performance of any size of wind turbine rotor.
 SPECIFIED RATED CAPACITY:-
Specified Rated capacity (SRC) is an important index which is used to compare a
variety of wind turbine designs.
It varies between 0.2 (for small rotors) and 0.6 (large rotors).

19. 13
 GEAR BOX:-
The power from the rotation of the wind turbine rotor is transferred to
the generator through the power train, i.e. through the main shaft, the gearbox and
the high speed shaft.
The gearbox in a wind turbine does not "change gears". It normally has a single
gear ratio between the rotation of the rotor and the generator. For a 600 or 750 kW
machine, the gear ratio is typically approximately 1 to 50.
The picture below shows a 1.5 MW gearbox for a wind turbine. This particular
gearbox is somewhat unusual, since it has flanges for two generators on the high
speed side (to the right). The orange gadgets just below the generator attachments
to the right are the hydraulically operated emergency disc brakes. In the
background you see the lower part of a nacelle for a 1.5 MW turbine.[2]
Fig.1.7-Gear box

20. 14
 WECS Technology:(Wind Energy Conversion System)
A WECS is a structure that transforms the kinetic energy of the incoming air
stream into electrical energy. This conversion takes place in two steps, as follows.
The extraction device, named wind turbine rotor turns under the wind stream
action, thus harvesting a mechanical power. The rotor drives a rotating electrical
machine, the generator, which outputs electrical power. Several wind turbine
concepts have been proposed over the years. A historical survey of wind turbine
technology is beyond the scope here, but someone interested can find that in
Ackermann (2005). There are two basic configurations, namely vertical axis wind
turbines (VAWT) and, horizontal axis wind turbines (HAWT). Today, the vast
majority of manufactured wind turbines are horizontal axis, with either two or
three blades. HAWT is comprised of the tower and the nacelle, mounted on the top
of the tower. Except for the energy conversion chain elements, the nacelle contains
some control subsystems and some auxiliary elements (e.g., cooling and braking
systems, etc.).[2]
Fig.1.8-Horizontal axis wind turbine

21. 15
Chapter 4
Generating System:-
A wind turbine is a complex system in which knowledge from the areas of the
aerodynamics and mechanical, electrical and control engineering is applied
For the generating system, nearly all wind turbines currently installed use either
one of the following systems.
1.Squirrel cage induction generator
2.Doubly fed induction generator
3.Direct drive synchronous generator
In which first one is a fixed speed or constant speed one while others are variable
speed turbine.

22. 16
TYPES OF GENERATORS:-
1.SQUIRREL CAGE INDUCTION GENERATOR:-
GRID
Compensating
capacitors
Squirrel cage
induction
generator
Gear
box
Rotor
Rotor
Fig.1.9-Squirrel cage induction generator
 It is the oldest one.
 SCIGs are of robust construction and mechanically stable.
 Rotor consist of metallic bars, resistant to dirt and vibration
 It consists of a conventional, directly grid coupled squirrel cage induction
generator.
 The slip and the rotor speed varies with the amount of power generated
 Its draw back is it always consumes reactive power, which is undesirable in
most of the cases, particularly in the case of large turbines and weak grid.
 It can be always be partly or fully compensated by capacitors in order to
achieve a power factor close to one.

23. 17
 PRINCIPLE OF OPERATION:-
Squirrel Cage induction generators produce electrical power when their rotor is
rotated faster than the synchronous frequency. For a typical four-pole motor (two
pairs of poles on stator) operating on a 60 Hz electrical grid, synchronous speed is
1800 rotations per minute. Similar four-pole motor operating on a 50 Hz grid will
have synchronous speed equal to 1500 rpm. In normal motor operation,stator flux
rotation is faster than the rotor rotation. This is initiating stator flux to induce rotor
currents, which create rotor flux with magnetic polarity opposite to stator. In this
way, rotor is dragged along behind stator flux, by value equal to slip. In generator
operation, a prime mover (turbine, engine) drives the rotor above the synchronous
speed. Stator flux still induces currents in the rotor, but since the opposing rotor
flux is now cutting the stator coils, active current is produced in stator coils, and
motor is now operating as a generator, and sending power back to the electrical
grid.[3]
 GRID CONNECTED INDUCTION GENERATOR:-
Grid connected induction generators develop their excitation from the Utility grid.
The generated power is fed to the supply system when the IG is run above
synchronous speed.

24. 18
2.DOUBLY FED INDUCTION GENERATOR:-
Fig.2.0-Doubly fed induction generator
 Widely used for variable speed generation .
 Reduced power converters rated 30% of nominal power .
 Stator is directly connected to the grid.
 Gearbox combined mechanism is required.
 Fault handling capacity is poor.
GRID
Doubly fed
induction
generator
Gear
box
Rotor
Rotor
converter

25. 19
 OPERATION: -
When the rotor speed is greater than the rotating magnetic field from stator, the
stator induces a strong current in the rotor. The faster the rotor rotates, the more
power will be transferred as an electromagnetic force to the stator, and in turn
converted to electricity which is fed to the electric grid. The speed of asynchronous
generator will vary with the rotational force applied to it. Its difference from
synchronous speed in percent is called generator‘s slip. With rotor winding short
circuited, the generator at full load is only a few percent.
With the DFIG, slip control is provided by the rotor and grid side converters. At
high rotor speeds, the slip power is recovered and delivered to the grid, resulting in
high overall system efficiency. If the rotor speed range is limited, the ratings of the
frequency converters will be small compared with the generator rating, which
helps in reducing converter losses and the system cost.
Since the mechanical torque applied to the rotor is positive for power generation
and since the rotational speed of the magnetic flux in the air gap of the generator is
positive and constant for a constant frequency grid voltage, the sign of the rotor
electric power output is a function of the slip sign. Crotor and Cgrid have the
capability of generating or absorbing reactive power and can be used for
controlling the reactive power or the grid terminal voltage. The pitch angle is
controlled to limit the generator output power to its normal value for high wind
speeds. The grid provides the necessary reactive power to the generator.[4]

26. 20
 CONVERTERS:-Fig.2.1-A DFIG and wind turbine system
Currently DFIG wind turbines are increasingly used in large wind farms. A typical
DFIG system is shown in the below figure. The AC/DC/AC converter consists of
two components: the rotor side converter Crotor and Grid side converter Cgrid
.These converters are voltage source converters that use forced commutation power
electronic devices (IGBTS) to synthesize AC voltage from DC voltage source. A
capacitor connected on DC side acts as a DC voltage source. The generator slip
rings are connected to the rotor side converter, which shares a DC link with the
grid side converter in a so called back –to-back configuration. The wind power
captured by the turbine is converted into electric power by the IG and is transferred
to grid by stator and rotor windings. The control system gives the pitch angle
command and the voltage commands for Crotor and Cgrid to control the power of
the wind turbine, DC bus voltage and reactive power or voltage at grid
terminals.[1]

27. 21
3.DIRECT DRIVE SYNCHRONOUS GENERATOR:-
GRID
Direct drive
synchronous
generator
Rotor
Rotor
Converter
Fig.2.2-Direct drive synchronous generator
 In this case generator is completely decoupled from the grid by a power
electronics converter connected to the stator winding.
 Most efficient Synchronous Generator is direct drive PMSG.
 Noise reduction is achieved as gear boxes are eliminated.
 For offshore applications increased oil spills from gear boxes are eliminated.
 More reliable.
 Cost , weight and size is more than DFIGs.

28. 22
CONCLUSION:-
 Most adopted generator system is DFIG equipped with a converter since less
weight and cost.
 For large wind energy systems, direct drive PMSGs are preferred due to better
reliability and efficiency.
 Full power converters can reduce the effects of grid voltage unbalances in the
generator.
FUTURE WORK:-
The parameters of the controllers can be improved or advanced control methods
can be used in future to improve the stability and dynamic performance of grid
connected induction generator.

29. 23
REFERENCES:-
• A.Mogstad, M.Molinas, P.Olsen and R.Nilsen, “A Power Conversion System
for offshore wind parks”, IEEE transactions on Industrial Electronics, vol 58,
no.4, Nov 2008.
• Kaigui Xie, Zefu Jiang and Wenyuan Li, “Effect of Wind Speed on Turbine
Power Converter Reliability Wind”, IEEE transactions on Industrial
Electronics, vol 27, no.1, March 2012.
• B.Rabelo and W.Hofman, “Control of an Optimised power flow in wind
power plants with doubly fed induction generators”, IEEE on Power
Electronics, June 2003.
• Schwartz, M.N.; Elliott, D.L.; Gower, G.L. (1992). "Gridded State Maps of
Wind Electric Potential." Windpower '92 Conference; October 19-23, 1992;
Seattle, Washington. Washington, DC: American Wind Energy Association;
pp. 50-58.

30. 24

31. 25

32. 26

33. 27

34. 28

35. 29