Over view of Multi-Megawatt Wind Turbines with the working principles of Wind Energy.

1. Over view of MULTI Mega Watt
WIND TURBINES
BY:-ANUPAM B.SHRIVASTAVA
U14EE021

2. CONTENTS
 Introduction
a. Statistics
Origin Of Wind
a. Generation
b. Fundamental of Wind
Technology
c. WECS Generation
Technology
 Wind Turbine
 Generators
 Conclusion
 References

3. INTRODUCTION
 The total world demand from solar power 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 7M.W, which is same as world energy
consumption.
 So the development of non-conventional energy
source is very; economical.

4. 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.
 In India during the mid summer due lack of hydro
power generation which is one of the main source of
energy there is desperate need for energy. This can be
meet to some extent by wind energy as there are very
high winds during this period.

5. Benefits & Facts of Wind Power:-
Benefits:-
• Clean and endless fuel,
• Local financial development,
• Modular and scalable technology,
• Energy price stability, &
• Reduced dependence on imported fuels.
Facts:-
• 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 announced Jaisalmer wind farm is
largest wind farm in India crossed 1,000MW(or 1GW)
capacity.

6. Statistics:-
• According to the Global Wind Report 2016,the total installed
wind capacity at the end of 2016 is 248 GW. Out of the total
capacity India installed wind power generation capacity stood at
about 16085MW constitute 6.8% of global wind power capacity.

7. Wind energy-India’s 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.
• 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 and now it is 16085MW by
2016.

8. Origin of Wind & Generation:-
 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.
 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.
Rotor
Generator
Grid
Mechanical
power
(translation)
Mechanical
power
(rotation)
Electrical
power

9. Fundamentals of Wind 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.
• For constant rotor speed: some wind turbines have
motors/controllers that drive the blades when the wind is not
strong enough.
Generators & Metallic Bars:-
• Types of generators are
1.Induction Generators
2.Permanent Magnet Synchronous Generators.
• Metallic bars are
1.Circular metallic bar
2.Spring type metallic bar.

10. Wind Turbine and Parts:-
1.According to Protection:-
•Gear box
•Controller
•Yaw drive
•Brake
2.According to Regulation:-
•Nacelle
•Anemometer
•Yaw motor
•Wind vane
3.According to main parts:-
•Blades
•Rotor
•Brake
•Low speed shaft
•High speed shaft

11. Power Flow & Torque Formula:-
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 )

12. Torque formula:-
P = 
 = P  n  30
 =   n30
Where,
• P = Output in N·m/s (1N·m/s = 1 W = 0.00136 metric hp)
•  = Torque in N m
• ω = Angular speed in s-1
• n = Rotational speed in rpm

13. Formulas for wind turbine:-
1.Tip speed ratio:-It is used to describe the performance of any size
of wind turbine rotor.
  V
Where,
• ω is rotational speed of rotor (in rpm),
•  is the radius of the swept area (in meter),
• The tip speed ratio λ ,
• V is velocity
2.Specified Rated Capacity:-It is used to compare a variety of wind
turbine designs.
SRC=Power rating of Generator / Rotor swept area
It varies between 0.2 (for small rotors) and 0.6 (large rotors).

14. Wind Turbine:-
Wind speed:-TIP SPEED RATIO
•Direction of wind
•Blade size:-SPECIFIED RATED CAPACITY
•Mechanical gears involved in its design:-GEAR BOX

15. 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.

16. WECS Tech (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.
• 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.).

17. 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

18. 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.
GRID
Compensating
capacitors
Squirrel cage
induction
generator
Gear
box
Rotor
Rotor

19. 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).
• The 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.
GRID
Compensating
capacitors
Squirrel cage
induction
generator
Gear
box
Rotor
Rotor

20. 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

21. 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.
• 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.
GRID
Doubly fed
induction
generator
Gear
box
Rotor
Rotor
converter

22. Converters:-
• 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 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.

23. 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.
GRID
Direct drive
synchronous
generator
Rotor
Rotor
Converter

24. 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.

25. 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.

26. THANK YOU