Grid Friendly Wind Plant Controls

Grid Friendly Wind Plant Controls

Nicholas MillerKara ClarkRobert DelmericoMark Cardinal

NY Advanced Energy Forum November, 2009 Long Island, New York

GEEnergy

2 /GE Energy: MIPRO 2009

What is a Wind Plant?


•

Wind plants have a greater impact on the grid

•

Displace other generation, so wind needs to provide its share of system support

•

Continuity of wind generation contribution becomes essential to grid reliability

•

Behavior during disturbances needs to be predictable

As Wind Power Plants increase in size and number …

“Grid friendliness”

is essential to wind energy’s continued growth


Grid Friendly Wind Power Plant

Not trip during faults and other system disturbances …ride through capability: WindRIDE-THROUGHTM

What makes a Wind Plant “Grid Friendly”?


Ride-Thru Capabilities

Medium voltage bus drops to 0.0

Power recovers to pre-

disturbance level in <200ms

GE's Standard WindRIDE-THRU Offerings

0

20

40

60

80

100

120

-1.0 0.0 1.0 2.0 3.0 4.0 5.0 6.0

Time (seconds)

Volta

ge a

t Poi

nt o

f In

terc

onne

ctio

n (P

erce

nt)

200 ms

LVRT

ZVRT

3-phase zero retained voltage, 200ms fault:

(GE Standard ZVRT offering) P, Q (Mw,Mvar)

Field Test Results (2.5 unit)


3-phase 18.5% retained voltage, 700ms fault: P, Q (Mw,Mvar)

Reactive Power well behaved: supports grid

during voltage depression


Not trip during faults and other system disturbances …ride through capability

Regulate plant voltage & reactive power : WindCONTROLTM



Voltage at POI

Wind Plant Power Output

Voltage & Reactive Power ControlsActual measurements from a

162MW wind plant

Wind Plant Voltage

•

Regulates Grid Voltage at Point of Interconnection

•

Minimizes Grid Voltage Fluctuations Even Under Varying Wind Conditions

•

Regulates Total Wind Plant Reactive Power through Control of Individual Turbines

Average Wind Speed

Voltage and Reactive Power Regulation

Like A Conventional Power Plant


Regulate plant voltage and reactive power

Limits the amount and/or rate of change of power from variations in wind speed … Ramp Rate Control :WindCONTROLTM



30 MW Plant Behavior

0

5000

10000

15000

20000

25000

30000

35000

4:30:00AM

4:38:00AM

4:46:00AM

4:54:00AM

5:02:00AM

5:10:00AM

5:18:00AM

5:26:00AM

5:34:00AM

5:42:00AM

5:50:00AM

5:58:00AM

6:06:00AM

6:14:00AM

6:22:00AM

6:30:00AM

Time

Pow

er k

W

0

5

10

15

20

Actual powerWind speed

Curtailment example (30 MW plant)


Regulate plant voltage and power

Limits the rate of change of power from variations in wind speed … Ramp Rate Control

React to changes in grid frequency … Frequency Droop: WindCONTROLTM



Under-Frequency Droop Response

10% Power Increase

4% Frequency Reduction

Freq

uenc

y (H

z)

Pow

er (k

W)

Function has High Opportunity Cost: To Be Used Sparingly

Initial Steady-State Conditions:

•

Power curtailed to 90% of available wind

•

2.5% power increase for 1% frequency drop

Test:

•

4% frequency ramp-

down @ 0.125 Hz/sec

•

10% increase in plant power with 4% under-frequency

Not trip during Faults and other System Disturbances … ride through capability

Regulate Plant Voltage and Power

Limits the Rate of Change of Power from Variations in Wind Speed … Ramp Rate Control

React to Changes in Grid Frequency … Frequency Droop

Provide reactive power all the time: WindFREETM

Reactive Power



Turb

ine

kVAR

75Time (seconds)

15000

1500

Turb

ine

kVAR

75Time (seconds)

15000

1500

WindFREE Reactive Power

•

Wind Turbine converter can deliver reactive power (kVAR) without wind (kW)

•

Benefits weak grids and systems with high wind penetration

•

Voltage support continues without active power generation…even following trips

Active

Power(zero)

Reactive

Power


Reactive Power - even without wind:A valuable option – An unreasonable requirement

Not trip during Faults and other System Disturbances … ride through capability

Regulate Plant Voltage and Power

Limits the Rate of Change of Power from Variations in Wind Speed … Ramp Rate Control

React to Changes in Grid Frequency … Frequency Droop

Provide reactive power all the time …

Provide inertial response to large under-frequency events: WindINERTIATM



Field Tests Results:

Test count:8 m/s -

19 tests10 m/s –

19 tests14 m/s –

52 tests

0

300

600

900

1200

1500

1800

0 10 20 30 40 50 60 70 80

Time (Seconds)

Pow

er (k

W)

8 m/s Avg Meas 10 m/s Avg Meas 14 m/s Avg Meas


Conclusions•

Wind Turbines can stabilize the grid voltage by rapid, smooth bidirectional control of reactive power

•

GE’s Wind Turbines can participate in system frequency control through active power control

•

GE now offers a suite of grid friendly features to meet these system needs

•

Need and demand for inertial response from

WTGs

has been growing

•

The latest feature (WindINERTIATM):–

has been field tested and a dynamic model created–

behavior is not identical to synchronous machines–

grid codes must recognize physical reality & constraints

Grid Friendly Wind Plants -

key to the continued successful large scale integration of wind power

Thank you

Nicholas MillerKara ClarkRobert

Delmerico

Mark Cardinal

GEEnergy

Grid Friendly Wind Plant Controls

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