control of wind power plants

7/23/2019 Control of Wind Power Plants

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1

Control of wind power plants

Poul Sørensen, Professor

Anca D. Hansen, Senior Researcher

Braulio Barahona, (former) Post Doc

DTU Wind Energy, Technical University of Denmark

DTU – Excellence since 1829

MISSIONDTU will develop and create valueusing the natural sciences and the

technical sciences to benefit society

2015-08-06



2


DTU organization

2015-08-06


DTU Wind Technology Expertise

2015-08-06

Wind Energy Division

Materials Research Division

Composites and Materials Mechanics

Materials Science and Characterisation

Fluid Mechanics

Test and Measurements

Wind Turbines Structures

Aerolastic Design

Meteorology

Wind Energy Systems

Fluid Dynamics

Composite Mechanics



3


Control issues

• List purposes of controlling wind power plants:

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4 wind turbine types

2015-08-06

GBASG

QC

ASG: Asynchronous generatorGB: GearboxQC: Reactive power compensationTR: TransformerVRR: Variable rotor resistance

TR

Type 1

GBASG

QC

TR

Type 2

VRR

GBASG

TR

Type 3

=

~

~

=

CHCL

CRGSC LSC

GSC: Generator side converterLSC: Line side converterCR: CrowbarC: DC link capacitorCH: ChopperL: Series inductanceSG: Synchronous generator

SG/ASG

GB

TR

Type 4

=

~

~

=

CHCL

GSC LSC



4


Outline

• General about wind turbine control

– blade angle control

– rotor speed control

• Electrical design and controllability / control strategies

– fixed speed

– variable speed

• Control examples

– Normal wind turbine operation control

• Fixed speed example (Active stall control)

• Variable speed example (doubly-fed and pitch control)

– Fault ride through wind turbine control• Active stall

• Doubly fed

– Wind turbine load reducing control

– Wind farm control

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Aerodynamic power – power curve

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0.0

0.2

0.4

0.6

0.8

1.0

1.2

0 5 10 15 20 25

Wind speed [m/s]

P o w e r ( p . u

. )

• P : aerodynamic power [W]

• U : wind speed

Power curve basedon 10 min averages



5


Aerodynamic power – power coefficient


• : air density [kg/m3]

• A : rotor (swept) area

• U : wind speed

• C p : power coefficient

• : blade pitch angle

• : tip speed ratio

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,2

1 3

pC AU P

U

R

U

v

tip

A

vtip

U

Front view Side view

U

vtip

Top view


Aerodynamic power – power coefficient

2015-08-06


• U : wind speed

• : air density [kg/m3]

• A : rotor (swept) area

• : blade pitch angle

• : tip speed ratio

• C p : power coefficient

,2

1 3

pC AU P

-90

-45

0

45

90

5

10

15

20

0.0

0.1

0.2

0.3

0.4

0.5

Cp

P i t c h a n g l e [ d e g ]

T i p s p e

e d r a t i o



6


Passive stall control

2015-08-06

W : relative speed seen from rotating blade

: angle of attack

L: lift

Power curve sensitive to• electrical grid frequency (3rd order)

• air density (1st order)

• dirt on blades

U

vtip = r

L

W

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0 5 10 15 20 25

Wind speed (m/s)

P o w

e r ( p . u . )

50 Hz

48 Hz

51 Hz

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

-5 0 5 10 15 20

Angl e of at tack [de g]

L i f t c o e f f i c i e n t


Pitch control

2015-08-06

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0 5 10 15 20 25

Wind speed [m/s]

P

o w

e r

( p .

u .

)

U

L

W

positive pitch

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

-5 0 5 10 15 20



vtip = r



7


Aktiv stall control (or kombi-stall)

2015-08-06

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0 5 10 15 20 25

Wind speed [m/s]

P

o w

e r

( p .

u .

)

U

L

W

negative pitch

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

-5 0 5 10 15 20



vtip = r


Fixed speed – active stall or pitch control

• Active (Combi) stall

• Moderate instantaneous responsegradients (fixed speed no problem)

• Slow blade angle control sufficient

• Pitch control

• Large instantaneous response gradientsfor power limitation (variable speeddesirable)

• Fast blade angle control necessary

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0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1.80

2.00

0 5 10 15 20 25

Wind speed [m/s]

P o w e r [ p u ] Pitch = 0 deg

Pitch = 5 deg

Pitch = 10 deg

Pitch = 15 deg

Pitch = 20 deg

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1.80

2.00

0 5 10 15 20 25

Wind speed [m/s]

P o w e r [ p u ] Pitch = 0 deg

Pitch = -3 deg

Pitch = -6 deg

Pitch = -9 deg

Pitch = -12 deg



8


Fixed speed – directly connected induction

generator

• WTR : wind turbine rotor speed

• gen : generator speed

• g : gear ratio

• 0 : electric grid radial speed (2 50 inEurope, 2 60 in USA)

• N pp : number of generator pole pairs

(typically 2 or 3)

• s << 1 : generator speed almost

“constant”

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Gear

box Induction

generator

0

pp

gen

1

N

sContactor

Main panel

bus bar

WTR

gen 0~

WTR gen g


Fixed speed – directly connected inductiongenerator

gen

2015-08-06

0 5 10 15 20 Time [ms]

0

N pp = 1

0

pp

gen

1

N

s

WTR gen g



• g : gear ratio



(typically 2 or 3)

• s : slip. s << 1 : generator speed almost

“constant”

gen



9




• g : gear ratio



(typically 2 or 3)


“constant”

Fixed speed – directly connected induction

generator

2015-08-06

0 5 10 15 20 Time [ms]

N pp = 2

0

pp

gen

1

N

s

WTR gen g

gen

20


Fixed speed – directly connected inductiongenerator

2015-08-060

Gear

box Induction

generator

Contactor

Main panel bus bar

WTR

gen 0~

0.5Slip

• WTR : generator speed


• g : gear ratio



(typically 2 or 3)


“constant”

WTR gen g

0

pp

gen

1

N

s



10


Fixed speed continuous operation - summary

• Wind turbines with directly connected induction generators are speedcontrolled by the generator torque, which is approximately proportionalto the slip (slip is difference between grid synchronous rotor speed andactual generator rotor speed).

• The generator can be “geared” by increasing the number of pole pairs

• Fixed speed turbines can control the speed by changing the number ofpole pairs, typically between 2 and 3, depending on the wind speed.

2015-08-06


Exercise 1: fixed speed

• Open excel sheet with C p data

• A fixed speed wind turbine with the C p data in table has rotor diameter 40m, tip speed 70 m/s. The air density i = 1.25 kg/m2. Make the power

curve if the pitch angle is 0 deg.

• At which pitch angle (integer degree) should the blades be mounted tothe hub to obtain the maximum power 600 kW? Hint: try to increase the

pitch angle negatively step by step and observe the power curve untilyou get the desired maximum.

• The turbine uses N pp=2 coupling of generator windings for high windspeeds and N pp=3 for low wind speeds. What is the tip speed for low wind

speeds?

• The turbine is passive stall controlled. Show the power curve for low windspeeds and high wind speeds, and identify the wind speed at whichswitching between generator speeds is feasible.

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11


Active Stall example

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• General operation modes active stall

– Power optimisation (lookup table)

– Power limitation (closed loop powercontrol)

• Normal operation (averagedpower, sample & hold)

• Overpower protection(instant. power, continuouspitching )

– Transition between optimisationand limitation

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0 5 10 15 20 25

Wind speed [m/s]

P o w

e r ( p .

u .

)


‐6

‐4

‐2

0

2

0 5 10 15 20 25


Wind

speed

[m/s]

0.0

0.1

0.2

0.3

0.4

0.5

‐10 ‐5 0 5 10

C p

Pitch

angle

[deg]

4 m/s

Power Optimisation

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12


Power Optimisation

2015-08-06

0.0

0.1

0.2

0.3

0.4

0.5

‐10 ‐5 0 5 10

C p

Pitch

angle

[deg]

4 m/s

5 m/s

6 m/s

7 m/s

8 m/s

9 m/s

10 m/s

11 m/s

12 m/s

13 m/s

‐6

‐4

‐2

0

2

0 5 10 15 20 25


Wind speed [m/s]


Power Limitation

2015-08-06

0.0

0.5

1.0

1.5

2.0

2.5

3.0

‐10

‐8

‐6

‐4

‐2 0

P o w e r [ M W ]

Pitch angle [deg]

13 m/s

‐6

‐4

‐2

0

2

0 5 10 15 20 25


Wind speed [m/s]



13


Power Limitation

2015-08-06

0.0

0.5

1.0

1.5

2.0

2.5

3.0

‐10 ‐8 ‐6 ‐4 ‐2 0

P o w e r [ M W ]

Pitch angle [deg]

13 m/s

14 m/s

15 m/s

16 m/s

17 m/s

18 m/s

19 m/s

20 m/s

21 m/s

22 m/s

23 m/s

24 m/s

‐6

‐4

‐2

0

2

0 5 10 15 20 25


Wind speed [m/s]


Transision

2015-08-06

‐6

‐4

‐

2

0

2

0 5 10 15 20 25


Wind speed [m/s]

Optimisation

Limitation

‐6

‐4

‐2

0

2

0 5 10 15 20 25


Wind speed [m/s]

Optimisation

Limitation

Transition

‐6

‐4

‐2

0

2

0 5 10 15 20 25

P i t c h a n g

l e [ d e g ]

Wind speed [m/s]

Optimisation

Limitation

Transition

Soft strategy



14


Control Circuit

2015-08-06

Actual

Power

Power

Setpoint

Lookup

S&H

anti windup

mode selection:- up: power limitation- down: power optimisation


Simulation Power Optimisation

2015-08-06

250.0200.0150.0100.0050.000.00 [s]

8.667

8.296

7.924

7.553

7.181

6.810

Windfilter_moving_average_Common Model: o1

Windfilter_moving_average_Common Model: yo

wind speed8.1 m/s

250.0200.0150.0100.0050.000.00 [s]

900.9

812.5

724.0

635.5

547.1

458.6

Power_in_kW_Common Model: power

Powerfilter_moving_average_Common Model: yo

el. power 758.5 kW

250.0200.0150.0100.0050.000.00 [s]

0.50

0.39

0.27

0.16

0.04

-0.070

pitch_control_I_Common Model: w2

pitch_control_I_Common Model: limit

pitch angle0.193 deg

power optimisation 0.000

D I g S I L E N T



15


Simulation Transition

2015-08-06

250.0200.0150.0100.0050.000.00 [s]

13.53

12.83

12.13

11.43

10.73

10.04



wind speed12.177 m/s

250.0200.0150.0100.0050.000.00 [s]

2381.

2189.

1998.

1806.

1615.

1424.



el. power 2117.9 kW

250.0200.0150.0100.0050.000.00 [s]

1.236

0.20

-0.839

-1.876

-2.913

-3.951



power optimisation

0.000

pitch angle-2.301 deg

D I g S I L E N T


Simulation Power Limitation

2015-08-06

250.0200.0150.0100.0050.000.00 [s]

26.11

24.72

23.32

21.92

20.52

19.12



wind speed23.5 m/s

250.0200.0150.0100.0050.000.00 [s]

2180.

2113.

2045.

1977.

1910.

1842.



el. power 2042.0 kW

250.0200.0150.0100.0050.000.00 [s]

1.288

0.02

-1.250

-2.519

-3.788

-5.057



pitch angle-4.768 deg

power limitation 1.000

D I g S I L E N T



16


Simulation Overpower

2015-08-06

250.0200.0150.0100.0050.000.00 [s]

18.42

16.52

14.62

12.72

10.81

8.914



wind speed10.89 m/s

wind speed16.5 m/s

250.0200.0150.0100.0050.000.00 [s]

2908.

2546.

2184.

1821.

1459.

1097.



el. power 2001.2 kW

el. power 2804.9 kW

250.0200.0150.0100.0050.000.00 [s]

1.336

-0.143

-1.622

-3.101

-4.580

-6.059



power optimisation 0.000

power limitation 1.000

pitch angle-2.5 deg

D I g S I L E N T


Overpower Protection

• Function of overpower protection

– Disable sample and hold

• (continuous controller action possible)

– Instantaneous power signal for power controller

• (controller uses instantaneous power instead of averagedpower)

– Overpower protection active for fixed period of time

2015-08-06



18


Exercise 2 – variable speed

• The Cp data is used for a variable speed / pitch controlled wind turbinewith rotor diameter 80 m. Specify equation for power curve inoptimisation region A-B

• Specify the corresponding relation between wind turbine rotor speed andpower

• The generator is a doubly fed induction generator with two pole pairs( N pp=2). The generator speed at rated wind speed is 1650 rpm (i.e. the

maximum generator speed). The rated grid frequency is 50 Hz. Find thegenerator slip corresponding to rated wind speed.

• The rated rotor tip speed (rotor speed at rated wind speed) is 70 m/s.Find the gear ratio.

• Specify the relation between generator speed and power in region A-B

• Specify the relation between generator speed and torque in region A-B

2015-08-06


Variable speed control loops

2015-08-06

+

-

PI

ref

grid P

meas

gen

meas

grid P ref

convP

Pel

P- curve

+

-

meas

gen

rated

gen

PI Pitch

actuator

c

Speed loop

Power loop



19


Doubly fed generator (DFG)

2015-08-06

DFIG control

Speed control loop Power control loop

Wind turbine control

Rotor side

converter control

Network side

converter control

Measurement

grid point M

AC

DC AC

DC

I rotor

gen

PWM PWM

N

T

ref

grid P

ref

grid Q

meas

dcU

meas

grid P

meas

grid P

meas

grid Q

meas

ac I

ref

dcU

rated ref

grid P ,


Doubly fed generator – power flow vs. rotorspeed

2015-08-06

0stator P

Sub-synchronous Over-synchronous

0stator P

S t a t o r c i r c u i t

0rotor P

Sub-synchronous Over-synchronous

0rotor P

Ro t o r c i r c u i t

rotor stator grid PPP mecP

Partial scale power converter

WRIG Grid

AC

DC AC

DC

Rotor side

converter Grid side

converter



20


Simulation – optimal power control (AB)

2015-08-06

360.00287.98215.96143.9471.919-0.1000 ..

0.200

0.150

0.100

0.050

0.000

-0.0500

G: Protor [MW]

360.00287.98215.96143.9471.919-0.1000 ..

1.2673

1.1064

0.945

0.784

0.624

0.463

G: Pstator[MW]

Gen_PQ_controller: Pgrid [MW]

360.00287.98215.96143.9471.919-0.1000 ..

9.2525

8.7577

8.2629

7.7682

7.2734

6.7787

Tower shadow model: Wind [m/s]

D I g S I L E N T

Below synchronous

(variable reference speed)

Below synchronous

(variable reference speed) Above synchronous

(fixed reference speed)


Simulation – optimal power control (AB)

2015-08-06

360.00288.00216.00144.0072.0000.000 ..

1.1813

1.1352

1.0890

1.0429

0.997

0.951

G: Speed

360.00288.00216.00144.0072.0000.000 ..

750804.

624643.

498482.

372322.

246161.

120000.

Transmission model: Aerodynamic rotor [Nm]

360.00288.00216.00144.0072.0000.000 ..

0.555

0.493

0.431

0.370

0.308

0.246

G: Electrical Torque in p.u.

360.00288.00216.00144.0072.0000.000 ..

1.0000

0.600

0.200

-0.2000

-0.6000

-1.0000

Limited_power_controller model: Pitch

D I g S I L E N T

Below synchronous

(variable reference speed)

Below synchronous

(variable reference speed) Above synchronous

(fixed reference speed)



21


Simulation - wind 7m/s – optimisation

strategy

2015-08-06

600.00479.98359.96239.94119.92-0.1000 ..

0.685

0.612

0.539

0.466

0.393

0.321

Gen_PQ_controller: P1

600.00480.00360.00240.00120.000.000 ..

8.3761

7.7706

7.1650

6.5594

5.9539

5.3483

Rotor wind model: wsfic

600.00480.00360.00240.00120.000.000 ..

1611.9

1540.1

1468.4

1396.7

1324.9

1253.2

Speed controller model: rotation_real

Speed controller model: rotation_ref

600.00480.00360.00240.00120.000.000 ..

0.420

0.206

-0.0075

-0.2213

-0.4352

-0.6490

Speed controller model: error

D I g S I L E N T

Power grid

Wind

Gen. Speed and Gen. ref. speed

Error


Simulation - wind 15 m/s

2015-08-06

600.00479.98359.96239.94119.92-0.1000 ..

2.0485

2.0318

2.0150

1.9982

1.9814

1.9647


600.00480.00360.00240.00120.000.000 ..

18.443

16.977

15.511

14.045

12.578

11.112


600.00480.00360.00240.00120.000.000 ..

1712.2

1700.5

1688.9

1677.3

1665.6

1654.0



600.00480.00360.00240.00120.000.000 ..

17.265

13.787

10.310

6.8323

3.3548

-0.1227

Power controller model: pitch

D I g S I L E N T

Power grid

Gen. Speed and gen. ref. speed

Pitch

Wind



22


Simulation - wind 22 m/s

2015-08-06

600.00479.98359.96239.94119.92-0.1000 ..

2.4742

2.3253

2.1765

2.0276

1.8787

1.7299


600.00480.00360.00240.00120.000.000 ..

27.182

24.936

22.691

20.445

18.200

15.954


600.00480.00360.00240.00120.000.000 ..

1856.4

1780.0

1703.6

1627.2

1550.8

1474.4



600.00480.00360.00240.00120.000.000 ..

25.835

22.162

18.489

14.816

11.143

7.4701

Power controller model: pitch

D I g S I

L E N T


Gain scheduling

2015-08-06

0 5 10 15 20 25 30-0.5

-0.45

-0.4

-0.35

-0.3

-0.25

-0.2

-0.15

-0.1

-0.05

0

d

dP

ba y

0 5 10 15 20 25 30

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1

d

dP

ba y z

11

1

d

dPK K pitchPI

d

dPK K PI system

pitchPI K K



23


Simulation - wind 22 m/s – gain schedulling

2015-08-06

600.00479.98359.96239.94119.92-0.1000 ..

2.4742

2.3254

2.1765

2.0277

1.8788

1.7300


600.00479.98359.96239.94119.92-0.1000 ..

27.182

24.935

22.688

20.441

18.194

15.947


600.00479.98359.96239.94119.92-0.1000 ..

1767.2

1730.8

1694.4

1657.9

1621.5

1585.0



600.00479.98359.96239.94119.92-0.1000 ..

28.381

25.594

22.806

20.018

17.230

14.442

Power control schedulling model: pitch

D I g S I L E N T

Power grid

Gen. Speed and Gen. ref. speed

Pitch


Fault-ride-through control

• Example active stall

– short circuit at “Fault Bus”

– isolation of fault

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24


No fault-ride-through control

2015-08-06

6.0004.8003.6002.4001.200-0.000 [s]

3.380

2.610

1.840

1.070

0.30

-0.470

WT Generator: Active Power in MW

6.0004.8003.6002.4001.200-0.000 [s]

1.030

0.85

0.68

0.50

0.33

0.15

WT Generator: Terminal Voltage in p.u.

6.0004.8003.6002.4001.200-0.000 [s]

1.100

1.078

1.056

1.034

1.012

0.99

WT Generator: Speed in p.u.

6.0004.8003.6002.4001.200-0.000 [s]

1.800

0.85

-0.095

-1.043

-1.990

-2.938

WT Generator: Reactive Power in MVAr

D I g S I L E N T


Simple fault-ride-thorugh control: fast pitchto zero-power

2015-08-06

-14

-12

-10

-8

-6

-4

-2

0

2

4

4 5 6 7 8 9 10 11 12 1 3 14 15 16 1 7 18 19 2 0 21 2 2 23 24 2 5

wind speed [m/s]

p i t c h

a n

g l e

[ d e g ]

normal operation pitch

0.0 MW pitch



25


Short circuit simulated with fault-ride-

through control

2015-08-06

6.0004.8003.6002.4001.200-0.000 [s]

3.039

2.391

1.743

1.096

0.45

-0.200

WT Generator: Active Power in MW

6.0004.8003.6002.4001.200-0.000 [s]

1.098

0.91

0.72

0.53

0.34

0.15

WT Generator: Terminal Voltage in p.u.

6.0004.8003.6002.4001.200-0.000 [s]

1.077

1.058

1.038

1.019

1.00

0.98

WT Generator: Speed in p.u.

6.0004.8003.6002.4001.200-0.000 [s]

2.051

1.059

0.07

-0.926

-1.918

-2.910

WT Generator: Reactive Power in MVAr

D I g S I L E N T


Fault ride through – DFG with crowbar

2015-08-06

Crowbar

DFIG

~=

~~~

Power convertercontrol

ref Qref P

Control mode :• normal operation• fault operation

~=

RSC GSC

Faultdetection

Drive train

with gearbox

Wind turbine

Pitch anglecontrol

DFIG system – control and protection

Aerodynamics

k

c



26


Crowbar effects

• On voltage dip:

– RSC overcurrents

– Crowbar activtates / RSCdisconnects

– DFG behaves as SCIG (nocontrol)

– GSC can still be used as aSTATCOM

• Effect of increased crowbarresistance :

– improves the torquecharacteristic

– reduces reactive powerdemand

– improves dynamic stability ofthe generator

2015-08-06

Damping controller

-1 -0.5 0 0.5 1 1.5 2 2.5 3-25

-20

-15

-10

-5

0

Speed [p.u.]

R e a c t i v e p o w e r [

M v a r ]

. . . .

-1 -0.5 0 0.5 1 1.5 2 2.5 3-3

-2

-1

0

1

2

3

Speed [p.u.]

E l e c t r o m a g n e t i c

t o r q u e

[ p . u . ]

crowbar crowbar crowbar R R R 321

crowbar crowbar crowbar R R R 321


Load reduction – active damping

2015-08-06

Wind

speed

ref

grid

ref P

-+

Damping controller

PIOptimal

speed

10.007.505.002.500.00 [s]

1.150

1.125

1.100

1.075

1.050

1.025

10.007.505.002.500.00 [s]

3.0E+4

2.0E+4

1.0E+4

0.0E+0

-1.0E+4

10.007.505.002.500.00 [s]

10.00

8.000

6.000

4.000

2.000

0.00

10.007.505.002.500.00 [s]

2.40

2.20

2.00

1.80

1.60

1.40

1.20

D I g S I L E N T

G e n e r a t o r s p e e d

[ p u

]

Withoutdampingcontroller Withdampingcontroller

M

e c h a n

i c a l t o r q u e

[ N m

]

[sec]

[sec]

[sec]

[sec]

P i t c h a n g

l e [ d e g

]

A e r o .

p o w e r

[ M W ]

10.007.505.002.500.00 [s]

1.150

1.125

1.100

1.075

1.050

1.025

10.007.505.002.500.00 [s]

3.0E+4

2.0E+4

1.0E+4

0.0E+0

-1.0E+4

10.007.505.002.500.00 [s]

10.00

8.000

6.000

4.000

2.000

0.00

10.007.505.002.500.00 [s]

2.40

2.20

2.00

1.80

1.60

1.40

1.20

D I g S I L E N T

G e n e r a t o r s p e e d

[ p u

]

Withoutdampingcontroller Withoutdampingcontroller Withdampingcontroller Withdampingcontroller

M

e c h a n

i c a l t o r q u e

[ N m

]

[sec]

[sec]

[sec]

[sec]

P i t c h a n g

l e [ d e g

]

A e r o .

p o w e r

[ M W ]



27


Integrated design analysis

and load reduction

• Integrated analysis model

– Aeroelastic model of windturbine (HAWC2)

– Pitch control (Simulink)

– Asynchronous machine +control (Simulink)

• Rotor and Statorfluxes

• Current and powercontrol of rotorside converter

• Resonant dampingcontrol

2015-08-06


Resonant damping control – load reductionUnbalanced fault

2015-08-06

Electrical loads:Generator rotor current

Structural loads:Tower top side-to-side moment



28


Resonant damping control – load reduction

2015-08-06

Load ranges(max – min)

Equivalent loads(fatigue)


Storm control

High Wind Shut Down High Wind Ride Through

(SIEMENS HWRT™)

2015-08-06



29


Offshore wind power variability 2020

2015-08-06


Wind farm control – wind power plants

• Contribute to control of grid voltage: amplitude and frequency, like otherpower plants

• Indirect grid control: active and reactive power control

2015-08-06



30


Balance control

• Balance control provides power output according to reference signal

• Balance control implemented in first time in Horns Rev 2002

• Why ramp limitation

2015-08-06

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 100 200 300 400 500 600

Time [s]

P o w e r [ p u . ]

PavailPbalPref,wf


Delta control

• Delta control provides fixedreserve

• Delta control implemented firsttime in Horns Rev 2002

• Reserve can be utilised infrequency control (droop anddeadband)

2015-08-06

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 100 200 300 400 500 600

Time [s]

P o w e r [ p u . ]

Pref,wf

Power

Frequency

Pavail

f s f s+ f d f d +

PdelPavailPdelPdel



31


Double fed wind turbine – power control

2015-08-06

Wind turbine controller Wind turbine controller Wind turbine controller

Power

control

meas

Speed

control

pitch

gen

ref P

max ~~

ref P


Double fed wind farm – power control

2015-08-06

Wind turbine controller Wind turbine controller Wind farm controller Operator Wind turbine controller

Power

reference

setting

Pbalance

P

Ramp rate settings

Dispatch

controlPower

control

wf

ref P

wf

measP

meas

Speed

control

pitch

gen

ref P

~~

inst

availP

measP

ref P

max



32



2015-08-06


Power

reference

setting

Pbalance

P

Ramp rate settings

Dispatch

controlPower

control

wf

ref P

wf

measP

meas

Speed

control

pitch

gen

ref P

ref Speed

optimum

~~

measu

inst

availP



2015-08-06


Power

reference

setting

Pbalance

P

Ramp rate settings

Dispatch

controlPower

control

wf

ref P

wf

measP

meas

Speed

control

pitch

gen

ref P

ref Speed

optimum

Wind

speeds

forecasts ~~

measu

inst

availP

t expu



33


Double fed wind farm – frequency control

2015-08-06


Power

reference

setting

Pbalance

P

Ramp rate settings

Droop settings

Deadband settings

Dispatch

controlPower

control

wf

ref P 0

meas f

wf

ref P

wf ref

P

wf

measP

meas

Speed

control

pitch

gen

ref P

ref

Speed

optimum

~~

measu

inst

availP

t expuWind

speeds

forecasts


Wind farm power control – wind turbines

2015-08-06

350.0280.0210.0140.070.000.00 [s]

21.00

18.00

15.00

12.00

9.00

6.00

350.0280.0210.0140.070.000.00 [s]

2.10

1.80

1.50

1.20

0.90

0.60

0.30

350.0280.0210.0140.070.000.00 [s]

1700.00

1600.00

1500.00

1400.00

1300.00

350.0280.0210.0140.070.000.00 [s]

20.00

16.00

12.00

8.00

4.00

-0.00

-4.00

D I g S I L E N T

Wind -WT1

Wind -WT2

Wind -WT3

Measured power -WT1

Measured power -WT2Measured power -WT3

Generator speed -WT1



Pitch angle -WT1

Pitch angle -WT2

Pitch angle -WT3

[ M W

]

[ m / s ]

[ r p m

]

[ d e g

]

[sec]

350.0280.0210.0140.070.000.00 [s]

21.00

18.00

15.00

12.00

9.00

6.00

350.0280.0210.0140.070.000.00 [s]

2.10

1.80

1.50

1.20

0.90

0.60

0.30

350.0280.0210.0140.070.000.00 [s]

1700.00

1600.00

1500.00

1400.00

1300.00

350.0280.0210.0140.070.000.00 [s]

20.00

16.00

12.00

8.00

4.00

-0.00

-4.00

D I g S I L E N T

Wind -WT1

Wind -WT2

Wind -WT3

Measured power -WT1

Measured power -WT2Measured power -WT3




Pitch angle -WT1

Pitch angle -WT2

Pitch angle -WT3

[ M W

]

[ m / s ]

[ r p m

]

[ d e g

]

[sec]




Wind farm power control

2015-08-06350.0280.0210.0140.070.000.00 [s]

6.50

6.00

5.50

5.00

4.50

4.00

3.50

350.0280.0210.0140.070.000.00 [s]

2.20

2.00

1.80

1.60

1.40

1.20

1.00

350.0280.0210.0140.070.000.00 [s]

2.20

2.00

1.80

1.60

1.40

1.20

350.0280.0210.0140.070.000.00 [s]

2.40

2.00

1.60

1.20

0.80

0.40

D I g S I L E N T

Dispatch reference power -WT1

Dispatch reference power - WT2


Available power -WT1



Wind farm available power Wind farm PCC measured power

[ M W ]

[ M W ]

[ M W ]

[ M W ]

[sec] 350.0280.0210.0140.070.000.00 [s]

6.50

6.00

5.50

5.00

4.50

4.00

3.50

350.0280.0210.0140.070.000.00 [s]

2.20

2.00

1.80

1.60

1.40

1.20

1.00

350.0280.0210.0140.070.000.00 [s]

2.20

2.00

1.80

1.60

1.40

1.20

350.0280.0210.0140.070.000.00 [s]

2.40

2.00

1.60

1.20

0.80

0.40

D I g S I L E N T


Dispatch reference power - WT2





Wind farm available power Wind farm PCC measured power

[ M W ]

[ M W ]

[ M W ]

[ M W ]

[sec]


Summary / conclusions

• Control can

– optimise production

– reduce structural loads

– support grid integration

• Controllability varies very much, depending on turbine design (fixed/varspeed, fixed/var pitch)

• QUESTIONS?

2015-08-06

control of wind power plants

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