Post on 11-May-2015
description
Windenergy 2010/11
Windenergy 2010/11
Windenergy 2010/11
Windenergy 2010/11
cp(lambda)
Windenergy 2010/11
basic scheme of a wind turbine
• wind - rotor - gear box - generator - grid integration
there are different concepts around:
different generators, multiple poles, synchronous or asynchronous
Windenergy 2010/11
aerodynamics
rotor
cp(!)
Wind
power class
FT , T
P,!R
Ug
fg
!g
Tg
drive - train powergenerator
.FT thrustT torqueTg torque of generatorP power!R rotation speed of rotor!g rotation speed of generatorUg grid voltagefg grid frequency
support structureFT
Center for Wind Energy Research
Turbine
hub main shaft
nacelle
gearbox
high speed shaft
generator
electrical / control system
Center for Wind Energy Research
Turbine
hub main shaft
nacelle
gearbox
high speed shaft
generator
electrical / control system
Windenergy 2010/11
design of wind turbine - resolved design
Windenergy 2010/11
design of wind turbine - resolved design
high speed shaftdisplaced - not in a line with main
shaft - why?
Windenergy 2010/11
• gear box
Windenergy 2010/11
compact - gearless design
Windenergy 2010/11
redundant design
Windenergy 2010/11
from Twele
Windenergy 2010/11
aerodynamics
rotor
cp(!)
Wind
power class
FT , T
P,!R
Ug
fg
!g
Tg
drive - train powergenerator
.FT thrustT torqueTg torque of generatorP power!R rotation speed of rotor!g rotation speed of generatorUg grid voltagefg grid frequency
support structureFT
extreme events ... foundation
Center for Wind Energy Research
installation of a windturbinefoundation concepts
Center for Wind Energy Research
installation of a windturbinefoundation
research: load measurements
Windenergy 2010/11
Center for Wind Energy Research
5MW WEC - electr. energy for about 10.000 to 20.000 persons
area = 12469 m2
Center for Wind Energy Research
installation of a windturbinefoundation
transport - logistics
Center for Wind Energy Research
construction
Center for Wind Energy Research
Center for Wind Energy Research
testung centers for foundation and blades
Center for Wind Energy Research
testung centers for foundation and blades
Windenergy 2010/11
Center for Wind Energy Research
investigation of the ground
Center for Wind Energy Research
floating WECs
Center for Wind Energy Research
floating WECs
Center for Wind Energy Research
floating WECs
Center for Wind Energy Research
floating WECs
Windenergy 2010/11
power generator
aerodynamics
rotor
cp(!)
Wind
power class
FT , T
P,!R
Ug
fg
!g
Tg
drive - train powergenerator
.FT thrustT torqueTg torque of generatorP power!R rotation speed of rotor!g rotation speed of generatorUg grid voltagefg grid frequency
support structureFT
Windenergy 2010/11
generator
• electric generator‣ transforms mechanical motion (power) into electric power P=UI‣ Faraday‘s law of induction
- changing magnetic field- generates voltage (emf)
‣ rotating magnet causes oscillating voltage out put
‣ demonstration
Uind = !d!dt
Windenergy 2010/11
synchronous / asynchronous generator
• synchronous‣ the frequency of the generator out is entirely fixed by the turbine
rotational frequency (wind) through the gearbox. Thus the output voltage frequency is synchronous with the high speed shaft frequency
‣ Wind turbines which use synchronous generators normally use electromagnets in the rotor which are fed by direct current from the electrical grid. Since the grid supplies alternating current, they first have to convert alternating current to direct current before sending it into the coil windings around the electromagnets in the rotor. The rotor electromagnets are connected to the current by using brushes and slip rings on the axle (shaft) of the generator.
Windenergy 2010/11
synchronous / asynchronous generator
• asynchroneous or cage or indiction generator‣ the frequency of the generator output is controlled by the
excitation from the main supply. Consequently the turbine rotation speed can vary slightly and is not exact synchoneous through the generator with the grid. The normal generator for this is an induction genertaor with magnetic excitation drawn from the grid
‣ the asynch. generator was designed as a motor but works also as generator. Its advantage is that is it very simple
further details see http://www.windpower.org/en/tour/wtrb/electric.htm
Windenergy 2010/11
reactive power
• due to complex resistance u and I get out of phase leading to reactive power - not useable
• additional impedence (inductivity for capacitance) can neutralize this - this can be achieved by synchronous generators
Center for Wind Energy Research
next decade : offshore
technical challenges / steps
wind potential - ground - selection of WEC - foundation - construction - grid connection - operation and maintenance
Center for Wind Energy Research
Center for Wind Energy Research
cables - grid connection
Center for Wind Energy Research
cables - grid connection
platform alpha ventus
Center for Wind Energy Research
cables - grid connection
platform alpha ventus
Center for Wind Energy Research
new cables GIL (gas isolated conductors)
Center for Wind Energy Research
new cables GIL (gas isolated conductors)
Windenergy 2010/11
aerodynamics
rotor
cp(!)
Wind
power class
FT , T
P,!R
Ug
fg
!g
Tg
drive - train powergenerator
.FT thrustT torqueTg torque of generatorP power!R rotation speed of rotor!g rotation speed of generatorUg grid voltagefg grid frequency
control system
pitch support structureFT
Windenergy 2010/11
• loads:‣ aerodynamic‣ gravitational ‣ - 600 kW machine will rotate some 2 108 times during a 20 year life
Windenergy 2010/11
• loads:‣ aerodynamic‣ gravitational‣ inertia - gyroscope, precession,
Windenergy 2010/11
• loads:‣ aerodynamic‣ gravitational‣ inertia - gyroscope, precession,
troque !" = !r ! !Fg
d!L
dt= !"
‣ Rotor must be well balanced - support in the center of mass
Windenergy 2010/11
• loads:‣ aerodynamic‣ gravitational‣ inertia - gyroscope, precession, centrifugal‣ operating loads - generator, brakes, yaw and pitch control‣ extreme loads - 50 year gust
- 3 or 5 sec gust = factor (1.4) * 50 year 10 min speed value‣ loss of load due to disconnection from grid + 1 year gust
- speed up until break sets in‣ tower shadow
Windenergy 2010/11
• classification of wind turbines IEC 61400‣ class I to IV
‣ class A - higher - B lower degree of turblence
• GL - includes load • danish standard DS 472
Windenergy 2010/11
• dynamic load and eigenmodes => resonances
• --- back board
Windenergy 2010/11
Windenergy 2010/11
• dynamic load and eigenmodes => resonances
Windenergy 2010/11
• spectral analysis of signals• rotational frequency• eigen modes at .4 Hz
Windenergy 2010/11
• spectral analysis of signals• rotational frequency• eigen modes at .4 Hz
closer to resonance
Windenergy 2010/11
• dynamic load and eigenmodes => resonances
Windenergy 2010/11
• dynamic load and eigenmodes => ressonances
Windenergy 2010/11
end
Windenergy 2010/11
10th lecture 14th of Jan
• control system purpose‣ to guarantee steady power production‣ to prevent damage in high wind speed‣ to keep mechanical loads minimal‣ to stay below max power given by the design of the
generator
• basic aspects‣ control of power production‣ emergency -
- high wind speed periods- interruption of grid connection (no load by generator)- emergency brake
Windenergy 2010/11
• simple control systems
Windenergy 2010/11
Windenergy 2010/11
t [sec]
u [m
/s]
0 1000 2000 3000 4000 5000 6000 7000
35
79
t [sec]
P [k
W]
0 1000 2000 3000 4000 5000 6000 7000
100
400
t [sec]
u [m
/s]
0 1000 2000 3000 4000 5000 6000 7000
1020
t [sec]P
[kW
]0 1000 2000 3000 4000 5000 6000 7000
1300
1700
t [sec]
u [m
/s]
0 1000 2000 3000 4000 5000 6000 7000
612
18
t [sec]
P [k
W]
0 1000 2000 3000 4000 5000 6000 7000
600
1400
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●
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●
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●
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2 4 6 8 10 12 14 16
0.0
0.2
0.4
0.6
0.8
1.0
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un [m/s]
PP r
●
●
LIDAR, IECLIDAR, Dynamic
Windenergy 2010/11
control system
• regular (non emergency control)‣ control quantities
- angle of attack- rotation speed (tip speed ratio)
‣ pitch control, passive pitch‣ stall control, active stall‣ rotor orientation‣ tip speed ratio
- Black borad details and tranparencies
Windenergy 2010/11
• control cases‣ fixed speed - fixed pitch‣ fixed speed - variable pitch‣ variable pitch - fixed pitch‣ variable speed - variable pitch
- explained by P(u); cp(lambda), cp(u) doagrams- - details on blackboard