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?
3 /GE Energy: MIPRO 2009
•
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
4 /GE Energy: MIPRO 2009
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”?
6 /GE Energy: MIPRO 2009
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)
7 /GE Energy: MIPRO 2009
3-phase 18.5% retained voltage, 700ms fault: P, Q (Mw,Mvar)
Reactive Power well behaved: supports grid
during voltage depression
Field Test Results (2.5 unit)
Not trip during faults and other system disturbances …ride through capability
Regulate plant voltage & reactive power : WindCONTROLTM
What makes a Wind Plant “Grid Friendly”?
9 /GE Energy: MIPRO 2009
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
Not trip during faults and other system disturbances …ride through capability
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
What makes a Wind Plant “Grid Friendly”?
11 /GE Energy: MIPRO 2009
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)
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: WindCONTROLTM
What makes a Wind Plant “Grid Friendly”?
13 /GE Energy: MIPRO 2009
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
What makes a Wind Plant “Grid Friendly”?
15 /GE Energy: MIPRO 2009
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
Field Test Results (2.5 unit)
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
What makes a Wind Plant “Grid Friendly”?
17 /GE Energy: MIPRO 2009
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
18 /GE Energy: MIPRO 2009
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
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