Upload
lydiep
View
245
Download
0
Embed Size (px)
Citation preview
Grid Interface for Wind- Advanced Functions
ARPA-eGreen Electricity Network Integration Workshop
Dec 13, 2010
Ravi RajuGE Global Research
2
Technology• Reliability & Efficiency
Cost• 85% in last 25 years
Policy• EU: 20% renewables by 2020• US: PTC, … 33 states have RPSs
Renewables Growth – Where we are
Global Wind & PV annual installations Last decade …. key drivers
3
UK:20% Renewables by 2020
Germany:20% Renewables by 2015
Spain:20 GW Wind by 2011
EU:20% Renewables by 2020
China:30 GW Wind by 2020
India:12 GW Wind by 2012
Japan:3 GW Wind by 2010
Targets in 73 countries
DOE Study: 20% wind energy by 2030
US: 33 states have Renewable Portfolio Standards California: 33% Renewables by 2020..
Renewables – Where we want to go
4
Wind Integration Challenges Are Broad
Longer time scale problems –grid dispatchability
Shorter time scale -dynamics and transients(power electronics )
Unit Commitmentand
Day-Ahead Scheduling
Load Following(5 Minute Dispatch)
Frequency and Tie-Line Regulation
(AGC)
Day-ahead and Multi-Day
Forecasting
Fast
er (s
econ
ds)
Ti
me
Fram
e
Slo
wer
(Yea
rs)
Planning and Operation Process
TechnologyIssues
Hour-Ahead Forecasting
and Plant Active Power Maneuvering and
Management
Resource andCapacity Planning
(Reliability)
Unit Dispatch
0
100
200
300
400
500
600
700
0 2000 4000 6000 8000
Hour
MW
Real-Time and Autonomous Protection and Control Functions
(AGC, LVRT, PSS, Governor, V-Reg, etc.)
Capacity Valuation(UCAP, ICAP)
andLong-Term Load
Growth Forecasting
2001 Average Load vs Average Wind
0
5,000
10,000
15,000
20,000
25,000
30,000
1 6 11 16 21
Hour
NYI
SO L
oad
(MW
)
0
200
400
600
800
1,000
1,200
1,400
1,600
Win
d O
utpu
t (M
W)
July load August load September load
July wind August wind September wind
0
500
1000
1500
2000
2500
3000
1 61 121
Minute s
MW
September Morning A ugust Morning May Evening October Evening April Af ternoon
1 Year
1 Day
3 Hours
10 Minutes
5
Challenges for Wind Integration
• Interconnection• Performance through voltage sags• Variable power – freq reg, ramp rates,
curtailment…
• Intermittency• Must be overcome with dispatchable
energy assets• Unit commitment based on day-ahead
forecasts• Regulation costs
• Lack of Inertia• Penetration of wind displaces
conventional assets with inertia
• Non-collocation with load• Long-distance T&D makes economics
more challenging
58.00
58.50
59.00
59.50
60.00
58.0 a fbul 90 Load 220.0 1 1 60.058.0 b fbul 90 Load 220.0 1 1 60.058.0 c fbul 90 Load 220.0 1 1 60.058.0 d fbul 90 Load 220.0 1 1 60.0
Time( sec )0.0 30.0
U n d e r - f r e q u e n c y l o a d s h e d d in g t h r e s h o ld
Voltage
Power
Voltage Ride-Through
Inertia - Effect on Frequency
2.70
2.90
3.10
3.30
3.50
3.70
3.90
4.10
0 50 100 150 200 250
seconds
MW
59.94
59.96
59.98
60.00
60.02
60.04
60.06
Hz
Grid weakness - Effect on Frequency
6
LVRT
Application CharacteristicsSingle WTGs Large Farms Multiple Farms
Low Penetration High Penetration
Perf
orm
ance
Req
uire
men
ts
Basi
c
Ad
vanc
ed
O/U VoltageOvercurrent
O/U Frequency
Anti-islanding
PF control
Voltage control(old DVAR)
Zero-PowerVoltage Control
None
Protection Volt/VAR Control
Active Power Control
None
LVRT – no trip(e.g. Taiban, E-ON)
Zero VRT – no trip(e.g. Quebec,
Western Australia)
LVRT with controlled current injection
Curtailment
Frequency Regulation
InertiaActive Anti-islanding,Torsional,
others
Coordinated Voltage Control
(WindVAR, WFMS)
State-of-the-Art for Wind Integration
7
Focus Areas:Security• Grid fault tolerance and recovery
Operability• Voltage regulation• Active power controls
Planning• Assessment and planning tools
Grid-Friendly Features
Low Voltage Ride-Thru
Voltage
Power
Pavail
Pout
Grid
Fea
ture
s
Volt/VAR control
High Penetration
Blackstart / Island Active Power
ControlsLow Voltage
Ride Thru
InertialResponse
Zero VoltageRide Thru
WindFREEVoltageControl
2003 2004 2005 2006
0
20
40
60
80
100
47 48 49 50 51 52
Active Power
Ramp Rate
Freq. Droop
Pow
erPo
wer
Frequency
Time
GE Wind – Grid Integration Features
8
Voltage Regulation
Measurements: 162MW wind plant• Regulates Grid Voltage at Point of Interconnection
• Minimizes Grid Voltage Fluctuations UnderVarying Wind Conditions
Voltage RegulationLike A Conventional Power Plant
Voltage at POI
Wind Plant Power Output
Wind Plant Voltage
Average Wind Speed
Average Wind Speed
Generator
Transformer
MainTransformer
45 mi.34.5kV
POI
ConverterControl WFMS
Wind Turbine
kW
kVAR
kW
kVAR230kV
Substation
9
GE WindRIDE-THRU Offerings
0
20
40
60
80
100
120
140
-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
HVRT
Synchronous generator swings dramatically
• Remains on-line and feeds reactive power through system disturbances
• Meets present and emerging grid requirement with Low/Zero Voltage Ride Through (LVRT/ZVRT) capability
• Meets transmission reliability standards similar to thermal generators
Fault Recovery• Voltage recovery better than
conventional generator
Voltage Ride - Through Capabilities
Power recovers to pre -disturbance level in <200ms
Medium voltage bus drops to 0.0
Voltage Level
3-Phase, 200ms, Zero Voltage Faultfrom WINDTEST report WT5491/06
10
Active Power ControlsTypical Grid Requirements
• Ramp rates• Power curtailment• Power droop w/ frequency
0.000
0.200
0.400
0.600
0.800
1.000
1.200
Available Power
Actual Power
Curtailment Example
Power Droop Test
2% Frequency Increase
50% Power Reduction
Pow
er (k
W)
Freq
uenc
y (H
z)
Pavail
PoutRamp Rate
Pow
er
Power Ramp Rates
11
Future Challenges and Directions
12
High Penetration Grid Dispatchability
Water Desalination
LMS 100 Gas Turbine
Wind Plant Controls(GEWE WindControls )
Grid Controls(NRPS XA/21)
Wind Farm
WFMS ControllerWFMS ControllerWFMS Controller
Wind Plant…• Coordination with grid controls• Effective use of forecasting
+ Balancing Generation…• Highly maneuverable• Fast start/stop• Good heat rates at partial load
+ Energy Storage Technologies…• Variable speed pumped hydro• Compressed Air, Batteries, Flywheels
+ Load Participation • Create new loads during low load/high
wind periods such as water desalination/purification
Wind Plant…• Coordination with grid controls• Effective use of forecasting
+ Balancing Generation…• Highly maneuverable• Fast start/stop• Good heat rates at partial load
+ Energy Storage Technologies…• Variable speed pumped hydro• Compressed Air, Batteries, Flywheels
+ Load Participation • Create new loads during low load/high
wind periods such as water desalination/purification
Water Desalination
LMS 100 Gas Turbine
Wind Plant Controls(GEWE WindControls )
Grid Controls(NRPS XA/21)
Wind Farm
WFMS ControllerWFMS ControllerWFMS ControllerWFMS ControllerWFMS ControllerWFMS Controller
Electric Vehicles
13
•Current Wind Turbines
– 690 V electrical system
- Significant Cabling Weight/Cost
- Large filters
•High frequency, High voltage conversion
- lighter cables
- big benefit in offshore applications
- need HV SiC devices?
Power Conversion: Migration to Higher Voltage
Present Future?
14
Offshoreconverter
station
On-shoreconverter
station
AC collectorsystem
DCcable On-shore
converterstation
DCcable
DC collectorsystem
• Reduce power conversion steps
• Higher efficiency + Lower cost
• Technical challenges : Power Electronics, Insulation, Protection
Present Future?
Power Conversion: DC interface for offshore wind
15
Enabling Technologies- Advanced Power Semiconductors & Passives
SiC Module, 10 kV, 120 amps (Cree,Powerex)Conduction drop < 6 V; Switching time < 100 ns
Si IGBT assembly, 10 kV, 120 ampsConduction drop > 12 V, Switching time > 2 s
220 kVA, 60 Hzdry-type xfmr
250 kVA, 20 kHz transformers (IAP, LANL)
HPE Program
DARPA/ONR HPE program: 10 kV Silicon Carbide MOSFETs, 20 kHz Magnetics ARPA-e ADEPT program: on-going program for 15kV IGBTs, …
Can enable -> More Efficient & Reliable, Compact Power Electronic Interface for Renewables!
• Tremendous control flexibility through power electronics – goal should be for a grid that is morestable with renewable energy sources
• EVs/ PHEVs .. potentially radical impact on the grid
• Great challenges & opportunities in grid integration of renewables and new loads through power electronics
Looking Ahead