Virtual Power Plant Modeling Simulation Gale Horst …smartgrid.epri.com/doc/07_AEP Smart Grid Project Modeling and... · Virtual Power Plant Modeling & Simulation Gale Horst

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Virtual Power PlantModeling & Simulation

Gale HorstProject Manager, Smart Grid Demonstrations

Electric Power Research Institute (EPRI)

Roger DuganSr. Technical Executive



American Electric Power (AEP) Virtual Power Plant Simulator (VPPS)


The Evolution of the Electric Utility SystemThe Evolution of the Electric Utility System

Before Smart Grid:One-way power flow, simple interactions

After Smart Grid:Two-way power flow, multi-stakeholder interactions

Adapted from EPRI Presentation by Joe HughesNIST Standards Workshop

April 28, 2008


Smart Grid Enables Energy StorageSmart Grid Enables Energy Storage

Adapted from EPRI Presentation by Joe HughesNIST Standards Workshop

April 28, 2008

But where is the best location/size for the storage ?


Migratory Path of Energy Storage Migratory Path of Energy Storage –– AEPAEP

Large Central Units

Storage at Grid Edge

Substation Batteries

Graphics adapted from an EPRI Presentation by Joe Hughes


CES(Community)

Devaluators:• Aesthetics

Locational Value of Electricity StorageLocational Value of Electricity Storage

120 V240 V69 kV 4 to 34 kV 480 V138 kV345 kV765 kV

Storage Value

Central Units Distributed Units

Devaluators:• No Backup• High Security Risk• Less effect on losses

Pumped Hydro(Central)

Devaluators:• Safety Concerns• No Load Diversity• No Cost Sharing• Little Grid Benefits •No Standardization

ResidentialNaS

(Substation)

Devaluators:• Complex Islanding• Storage Size & Location•Medium Security Risk


To Optimize StorageTo Optimize Storage

1.Very Close to Customers• Backup Power, • Buffer Customer Renewables

2.Grid-Connected• Load Leveling, • Volt / VAR support

3.Utility-Operated• Load Diversity (multiple customers on one storage)• Improved Safety• Optimizing Grid Performance

4.Utility-Owned• Standardization & Commodity Pricing• Socializing the Cost

Need an energy storage system with the following FOUR key features:


CES CES –– A Virtual Substation BatteryA Virtual Substation Battery

Local Benefits:1) Backup power2) Voltage correction3) Renewable Integration

Substation

Power LinesCommunication and Control Links

CES

CES is Operated as a Fleet offering a Multi-MW, Multi-hour Storage


CES CES –– A Virtual Substation BatteryA Virtual Substation Battery

Communication & Control Layout for

CES

Utility Dispatch Center /SCADACES Control Hub

Substation

Power LinesCommunication and Control Links

Integration Platform

CES CESCESCES

CES is Operated as a Fleet offering a Multi-MW, Multi-hour Storage

Grid Benefits:4) Load Leveling at substation5) Power Factor Correction6) Ancillary services

Local Benefits:1) Backup power2) Voltage correction3) Renewable Integration


Benefits of Local Energy Benefits of Local Energy StoraeStorae

• More reliable Backup Power to customers (closer)

• More scalable, flexible implementation (many small units)

• More efficient in buffering customer renewable sources

• More synergy with Electric Vehicle batteries

• Easier installation and maintenance (240 V)

• A Unit outage is less critical to the grid (smaller)

While Local Storage can function as a Multi-MW, Multi-hour Substation Battery, It has Inherent Advantages over Larger Batteries located in Substations:


Load Following Peak Shaving

Circuit Demand


Community Energy Storage Simulations

In the

AEP Smart Grid Demonstration

Roger DuganSr. Technical Executive



Circuit Diagram

84 Storage Elements25 kW each


Voltage Profile

Voltage Profile Plot

0.97

0.98

0.99

1

1.01

1.02

1.03

1.04

1.05

0 0.5 1 1.5 2 2.5 3 3.5 4

Distance from Substation

Per

Uni

t Vol

tage

V1V2V3


Storage Element Model in OpenDSS

% Eff. Charge/DischargeIdle | Discharge | Charge

Idling Losses

kW, kvar

kWh STORED

Other Key Properties

% ReservekWhRatedkWhStored%StoredkWRated

etc.


StorageController Element in OpenDSS

Discharge ModeCharge Mode

kW TargetDischarge Time

Total Fleet kW CapacityTotal Fleet kWh

et. al.

Storage “Fleet”Substation

V, IComm Link

Time + Discharge ratePeak ShavingLoad FollowingLoadshape


Example Simulations

Investigating 25, 50, and 75 kWh storage options with various

discharging schemes


Load Shapes With and Without StorageMode=Peak Shave, Target=8000 kW, Storage=75 kWh

Charge=2:00 @ 30%

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Base kWNet kW kWh Stored



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“Ran Out of Gas”


Load Shapes With and Without StorageMode=Load Follow, Time=12:00, Storage=75 kWh

Charge=2:00 @ 30%

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12:00 is too early Load declines after 12:00



Charge=2:00 @ 30%

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Load Shapes With and Without StorageMode=Time + fixed rate, Time=12:00 @ 30%, Storage=25 kWh

Charge=2:00 @ 30%

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Load Shapes With and Without StorageMode=Time + fixed rate, Time=12:00 @ 30%, Storage=25 kWh

Charge=2:00 @ 30%

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Quickly discharges to reserve kWh


Load Shapes With and Without StorageMode=Time + fixed rate, Time=14:00 @ 25% Storage=25 kWh

Charge=2:00 @ 30%

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Load Shapes With and Without StorageMode=Time + fixed rate, Time=14:00 @ 25% Storage=25 kWh

Charge=2:00 @ 30%

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Hours

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(Expanded Scale)


Conclusions

• 25 kWh storage is quickly depleted when used for day‐to‐day peak shaving– Have to be very careful with discharge strategy

• Load following with a later time trigger is likely more useful than a fixed discharge rate or an early time trigger

• 75 kWh would be “nice to have”– Costs are a factor


Discharge Algorithm Development

Scheduled Discharge

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(kW

)

Load without Battery

Load with Battery

Aug 3rd Aug 4th Aug 5th Aug 6th Aug 7th

Is it time to trigger ?



Scheduled Discharge

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(kW

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Load with Battery





Scheduled Discharge

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(kW

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Scheduled Discharge

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Scheduled Discharge

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)


Load with Battery



AEP Approach to Smart Grid Technology Simulations


Together…Shaping the Future of Electricity

Documents

Virtual Power Plant Modeling Simulation Gale Horst …smartgrid.epri.com/doc/07_AEP Smart Grid Project Modeling and... · Virtual Power Plant Modeling & Simulation Gale Horst