Simulating Power System Operations GRIDSCHOOL 2010 MARCH 8-12, 2010 RICHMOND, VIRGINIA INSTITUTE OF PUBLIC UTILITIES ARGONNE NATIONAL LABORATORY Thomas D. Veselka Center for Energy, Economic, and Environmental Systems Analysis Decision and Information Sciences Division ARGONNE NATIONAL LABORATORY [email protected]630.252.6711 Do not cite or distribute without permission MICHIGAN STATE UNIVERSITY
Simulating Power System Operations. GridSchool 2010 March 8-12, 2010 Richmond, Virginia Institute of Public Utilities Argonne National Laboratory Thomas D. Veselka Center for Energy, Economic, and Environmental Systems Analysis Decision and Information Sciences Division - PowerPoint PPT Presentation
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Simulating Power System Operations
GRIDSCHOOL 2010MARCH 8-12, 2010 RICHMOND, VIRGINIA
INSTITUTE OF PUBLIC UTILITIESARGONNE NATIONAL LABORATORY
Thomas D. VeselkaCenter for Energy, Economic, and Environmental Systems Analysis
Decision and Information Sciences DivisionARGONNE NATIONAL LABORATORY
The Supply Curve Shifts When Units Are Either Taken Off-Line or Brought Back Into Service
1,800 MW
500 $/MWh
Since the Supply Curve Is Typically Steeper at High Loads the Increase in Generation Cost Attributed to a Scheduled Outage is Less Expensive when Loads Are Low
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GridSchool 2010
0 1 2 3 4 5 6 7 8 9
Fossil Steam
Hydroelectric
Combined Cycle
Gas Turbine
Diesel Generator
Nuclear Steam
Forced Outage Rate (%)
Generating Units Unexpectedly Breakdown (Randomly Forced out of Service)
There are hundreds of causes for outages. The North American Electric Reliability Council (NERC) categorizes these into the following groups: Boiler Balance of plant Steam turbine Generator Pollution control equipment External Regulatory Personnel errors Performance
Generating Unit Forced Outages Add to System Uncertainty
Grid Operations Must Be Prepared to Immediately Fill the Generation Void when a Generator Suddenly Is Taken Off Line
Good Source: Generation Availability Dataset (GADS)
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It Is Very Unlikely that ALL Generating Units Will Be On-Line at any Point in Time when there Are Many Units in the System
Hydroelectric Power Plants Are an Important Component of Grid Operations in Some Systems
Very flexible operation Change operations quickly Large range of operations Good resource for ancillary services
No fuel required Very low production costs Zero air emissions
High fixed costs Expensive to build Maintain dam, reservoir, & plant
Environmental concerns Effect operations and economics
Limited energy source Cannot always operate at full capacity Uncertainty
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Reservoirs Are Multi-Purpose Resources Operations Consider Many Factors
Reservoir water storage and management Flood control Irrigation Environmental management Fish and wildlife (endangered species) Municipal and industry water supply Supply for generating units with steam
turbines Recreation Navigation Soil erosion Hydroelectric power generation
In Addition to Power Plant Equipment Limits,Operations Are also Constrained by Reservoir Limits
S t = S t-1 + I t - O t - D t - L t
t is current time,S is reservoir storage or content, I is reservoir inflow,O is reservoir outflow,D is reservoir diversion,L is reservoir loss (e.g., evaporation)
Turbine
Reservoir ElevationHead
Tail
Dam
PowerPlant
WaterIntake
Reservoir Volume
ReleaseFlow
SideFlows
Upstream Releases Elevation
LimitsMax
Min
Reservoir Storage Capacity Range from a Few Hours or Less to Multiple Years of Water Release
Run-of-River Hydro Has no Storage (cannot dispatch)
Minimum Release Rate
Peak Shaved
Remaining Loads
Peaking Capability(100 MW)
Mandatory Water Release Pattern
(1,200 MWh)
DiscretionaryRelease Pattern
(710 MWh)
Lo
ads
(MW
)G
eneratio
n (M
Wh
)
Capability: 150 MWMinimum Release: 50 MWGeneration: 1,910 MWh No Other Restrictions
Traditional Hydropower Plant Dispatch Focused on Displacing High Cost Thermal Generation
Market Driven Operations Yield a Very Different Generation Pattern
30
Hydropower Plants Are Often Cascaded, Adding to the Complexity of Operations
ToMontrose
ToRiffle
CurecantiSubstation
Blue Mesa
CrystalMorrow Point
ToFourCorners
BlackCanyon
The Aspinall Cascade Is a Tightly Coupled System with a High Level of Operational Interdependencies
In Many Situations More Expensive Bids Are Dispatched Because of Transmission Congestion
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GridSchool 2010
Source: T. Overbye, UIUC
Red indicates high LMPs or load pockets where lower cost
power cannot be delivered
Blue indicates low LMPs or generator pockets where lower cost power cannot be sent out
The Eastern Interconnect Contains Thousands of Busses and a Very Complex Transmission System
LMPs are the result of the transmission congestion
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Power Flows Down Path of Least Resistance(Power Transfer Distributions Factor – Pathway)
.0446
.569
2
.189
4 .0670
.1744
.714
0
.2860
.0007.0069
.28
80 .2819 .1
88
7
.18
13
.0601
.1001
.3881.3705
.241
5
Power Injection(Generation)
Power Sink (Load)
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GridSchool 2010
The System Operator Can Relieve Transmission Congestion by Opening Circuits (Once Opened, a Lower Cost Dispatch May Be Implemented)
Cap. 600 MWPC $20/MWh
Cap. 250 MWPC $100/MWh
Cap. 200 MWPC $50/MWh
Demand 450 MW
Cap. 600 MWPC $20/MWh
Cap. 250 MWPC $100/MWh
Cap. 200 MWPC $50/MWh
Demand 450 MW
Congested Line
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GridSchool 2010
Balancing Authority (BA) Maintain Load-Interchange-Generation Balance within an Area and Supports Interconnection Frequency in Real-Time
Tie-line Flows
Tie-line Flows
Tie-
line
Flow
sTie-Line Flows Are Scheduled to Take Advantage of Economic Power Transfers while at the Same Time Inadvertent Power Travels Down the Path of Least Resistance
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GridSchool 2010
In Addition to Spinning Reserves, Regulation Service Is Needed to Maintain Frequency
Reg
ulatio
n D
ow
n
Time
Load
Reg
ula
tio
n U
p
Time (minutes)
Reg
ula
tio
n S
ervi
ce (
MW
)
0
40
0 60-40
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Units that Provide Ancillary Service Have a Reduced Range of Scheduled Operation
Spinning reserves (SR)Affects maximum generation
Regulation services (RS)Affects minimum & maximum
generation Minimum Generation
When generation is off-line the unit cannot provide either spinning reserves or regulation services
Min
imu
mL
oad
Fo
llow
ing
Min
imu
mL
oad
Fo
llo
win
g
Increase Minimum
Decrease Maximum R
egu
lation
Service
SpinningReserves
Ca
pab
ility
(M
W)
Up
Down
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GridSchool 2010
Area Control Error (ACE) Is a Measure ofSystem Error in BA Interchange and Time Error
ACE = (Ta - Ts) – 10Bf (Fa - Fs) +/- Bt Te
Actual Versus Scheduled Net Interchanges (MW)
Over BA Tie-Lines
Actual Versus Target Frequency (Hz)
Area Bias per 0.1 Hz (MW/Hz)
Time Error(seconds)
Time Error Bias (MW/second)
slow
fast
clock
Reg
ulatio
n D
ow
n
Reg
ula
tio
n
Up
Time (minutes)
Re
gu
lati
on
Se
rvic
e (
MW
)
0
40
0 60-40 M
inim
um
Lo
ad
Fo
llo
win
g
Min
imu
mL
oad
Fo
llow
ing
Increase Minimum
Decrease Maximum
Reg
ula
tion
Serv
ice
Spinning Reserves
Cap
abili
ty (
MW
)
Up
Down
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Summary: Power System Operators Balance Supply & Demand
Dispatch generating units to meet load
Have a least-cost operating objective
Adjust grid topology to help relieve congestion
Maintain operating reserves to keep the lights on when there is an outage