integration€wind€energy€into the€grid · 2009. 6. 3. · 2/ ge€renewable€energy...
TRANSCRIPT
2 /GE Renewable Energy
2/19/2009
Network systems require that wind power plants:› Provide Controlled and Predictable Power Response From
Variations in Wind, Turbine and Grid Frequency
› Must remain connected to the grid following disturbances –inshort, they must remain stable
Good locations for wind plants often entail connectionto relatively weak transmission systems
As Wind Power Plants increase in size andcontribution …
Wind plants must performlike a conventional power plant
§ Does not trip during Faults and other SystemDisturbances … ride through capability
What makes a Wind Plant “Grid Friendly”?
4 /GE Renewable Energy
2/19/2009
Grid Fault RideThrough Requirements
OEM Response: Standard RideThroughRequirement That Covers Most Cases
Challenge:
• Requirements vary considerably bycountry/utility/voltage level
• Does not often distinguishbetween single phase vs threephase faults
• Voltage level specified at Point ofInterconnection (POI) … levels ateach at turbine terminals isdifferent depending upon plantdesign
• Assumes single fault eventsfollowed by recovery
0
20
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0.1 1 10
Time (s)
Volta
ge (%
)
France Umax France HVB1France HVA NGETNGET HVRT PortugalSpain Ireland >110 KVIreland<110 KV Ireland UmaxItaly Italy HVRTPoland eon
5 /GE Renewable Energy
2/19/2009
RideThru Capabilities• Remain online and feed reactive power
through system disturbances• Meets present and emerging grid
requirement with Low/Zero Voltage RideThrough (LVRT/ZVRT) capability
• Meets transmission reliability standardssimilar to thermal generators
Fault Recovery• Voltage recovery better than
conventional generator
Active Power
Reactive Power
Voltage
Apparent Power
ZeroVoltageEvent
Synchronous generatorswings dramatically
7 /GE Renewable Energy
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3Phase, 200ms, Zero Voltage Fault
Power recovers to predisturbance level in <200ms
Active Power (delivered to Medium Voltage bus)
Medium voltagebus drops to 0.0
Voltage Level
§ Does not trip during Faults and other SystemDisturbances … ride through capability
§ Regulates Plant Voltage and Power
§ Limits the Rate of Change of Power from Variations inWind Speed … Ramp Rate Control
§ Reacts to Changes in Grid Frequency … FrequencyDroop Control
What makes a Wind Plant “Grid Friendly”?
9 /GE Renewable Energy
2/19/2009
Voltage at POI
Wind Plant Power Output
Voltage RegulationActual measurements from a
162MW wind plant
Wind Plant Voltage
• Regulates Grid Voltage atPoint of Interconnection
• Minimizes Grid VoltageFluctuations Even UnderVarying Wind Conditions
Average Wind Speed
Voltage RegulationLike A Conventional Power Plant
Average Wind Speed
Generator
Transformer
MainTransformer
72 km34.5kV
POI
ConverterControl WFMS
WindTurbine kW
kVAR
230kV
Substation
10 /GE Renewable Energy
2/19/2009
Active Power Controls
Typical Grid Requirements> Ramp rates> Power curtailment> Power droop w/ frequency
Power Droop Test
0.000
0.200
0.400
0.600
0.800
1.000
1.200
Available Power
Actual Power
Curtailment Example
2% Frequency Increase
50% Power Reduction
Pow
er (k
W)
Freq
uenc
y (H
z)
Pavail
PoutRamp Rate
Pow
er
Power Ramp Rates
§ Does not trip during Faults and other SystemDisturbances … ride through capability
§ Regulates Plant Voltage and Power
§ Limits the Rate of Change of Power from Variations inWind Speed … Ramp Rate Control
§ Reacts to Changes in Grid Frequency … FrequencyDroop
§ Controls the Insertion and Removal of Large PowerBlocks … Startup and Shutdown Control
What makes a Wind Plant “Grid Friendly”?
12 /GE Renewable Energy
2/19/2009
Wind Plant Startup
Settings:
Turbines SequencedOn at 20 secondIntervals
Desired Ramp RateLimit 3MW/Min
Wind Plant PowerRamping at less than 3MW/Min
1 MinuteAverage RampRate (kW/sec)
Turbinestransitioning
Online
Pow
er (k
W)
Num
ber
of T
urbi
nes
Onl
ine
Wind Plant Output Controlled During Startup Conditions
13 /GE Renewable Energy
2/19/2009
Wind Plant ShutdownSettings:
Shutdown Interval Setto 5 Minutes
Wind PlantPower
Ramping toZero in 5 Mins N
umbe
r of
Tur
bine
s O
nlin
eTurbinestransitioning
Offline
Pow
er (k
W)
Wind Plant Output Controlled During Shutdown Conditions
§ Does not trip during Faults and other SystemDisturbances … ride through capability
§ Regulates Plant Voltage and Power
§ Limits the Rate of Change of Power from Variations inWind Speed … Ramp Rate Control
§ Reacts to Changes in Grid Frequency … FrequencyDroop
§ Controls the Insertion and Removal of Large PowerBlocks … Startup and Shutdown Control
§ Provides Reactive Power When Needed … Wind FreeReactive Power
What makes a Wind Plant “Grid Friendly”?
15 /GE Renewable Energy
2/19/2009
WindFREE Reactive Power
• Wind Turbine converter can deliverreactive power (kVAR) without wind (kW)
• Benefits weak grids and systems with highwind penetration
• Voltage support continues without activepower generation…even following trips
Reactive Power even without wind
16 /GE Renewable Energy
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2.5 WTG Reactive Power Capability
Cos 0.95
Cos 0.90
Available VARWindFREEReactive Power
§ Does not trip during Faults and other System Disturbances …ride through capability
§ Regulates Plant Voltage and Power
§ Limits the Rate of Change of Power from Variations in WindSpeed … Ramp Rate Control
§ Reacts to Changes in Grid Frequency … Frequency Droop
§ Controls the Insertion and Removal of Large Power Blocks …Startup and Shutdown Control
§ Provides Reactive Power When Needed … Wind Free ReactivePower
§ Provides inertial response to address underfrequency events …WindINERTIA
What makes a Wind Plant “Grid Friendly”?
18 /GE Renewable Energy
2/19/2009
Why Inertial Response: System Needs> Increasing Dependence on Wind Power
– Large Grids with Significant Penetration of Wind Power> Modern variable speed wind turbinegenerators do not contribute to
system inertia> System inertia declines as wind generation displaces synchronous
generators (which are decommitted)> Result is deeper frequency excursions for system disturbances> Increased risk of
– Underfrequency load shedding (UFLS)– Cascading outages
Inertial response will increase system security andaid large scale integration of wind power
19 /GE Renewable Energy
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58.0
58.5
59.0
59.5
60.0
60.5
0 10 20 30Time (Seconds)
Win
d Pl
ant P
OI B
us F
requ
ency
(Hz)
1000 MW Synchronous Machine
1000 MW Wind without WindINERTIA
1000 MW Wind with WindINERTIA
An Example:14GW, mostly hydro system, for trip of a large generator
Reference Case
Without WindINERTIA frequencyexcursion is ~4% worse
With WindINERTIAfrequency excursion is
~9% better
20 /GE Renewable Energy
2/19/2009
Making a Wind Plant “Grid Friendly”
ü Regulates Plant Voltage and Power
ü Reactive power regulation to meet grid needs …Dynamic VAR Control
ü Limits the Rate of Change of Power from Variations inWind Speed … Ramp Rate Control
ü Reacts to Changes in Grid Frequency … FrequencyDroop, Inertial Response
ü Controls the Insertion and Removal of Large PowerBlocks … Startup and Shutdown Control