Smart Grid Vision

Smart Grid Vision: Vision for a Holistic Power Supply and Delivery Chain

Stephen LeeSenior Technical Executive Power Delivery & Utilization

November 2008

2© 2008 Electric Power Research Institute, Inc. All rights reserved.

Smart GridTwo Way Communications….Sensors…….Intelligence

Smart Smart GridGrid

Need an Objective Assessment of the Potential for Smart Transmission and the Path to Achieve it

Hype


Smart GridTwo Way Communications….Sensors…….Intelligence

Information & Communication Enabled Power Infrastructure

Distribution ConsumerTransmission Substation Markets

Maximize Asset Utilization Real Time State Estimation & Measurement

Automate Asset Condition Assessment Enable Wide Area Monitoring & Control

Automate Fault Location Integrate Demand Responsive Resources

Transmission Applications


Current State – System Operations

2-4 Sec scan rates

Limited to info from lines and transformers at substations

MW, MVAR, KV breaker status

2

3

4

5

7

6

1

8

9

1011

12 13

14

15

1617

2

3

4

5

7

6

1

8

9

1011

12 13

14

15

1617

Limited Grid Visibility


Smart Transmission State – System Operations

750 +282j

250 +84j

100 +62j

20 + 8j

276 + 120j

130 + 8j

300 + 100j

750 + 262j 440

+ 200j

120 + 11j

350 + 150j

227 + 420j 704 + 308j

2

3

4

5

7

6

1

8

9

1011

12 13

14

15

1617

176 +88j

Higher speed scan rates

Allows more frequent analysis of system state

Enhanced Grid Visibility


Grid Enabled Technology PathwayRenewables Integration and T&D Efficiency Improvement

CAES: compressed air energy storage

FACTS: flexible AC transmission system

HVDC: high voltage direct current

RPS: renewable portfolio standards


End-uses & DR

Distribution SystemTransmission System

Energy Storage

Fuel Supply System

Fuel Source/Storage

Power Plants

Renewable Plants

Data CommunicationData Communication

Wide Area ControlWide Area Control

Sensors

Controllers

ZIP

M

Dynamic Load ModelsDynamic Power Plant Models

End-to-End Power Delivery Chain Operation & Planning

Monitoring, Modeling, Analysis, Coordination & ControlMonitoring, Modeling, Analysis, Coordination & Control


Alarm Management

Most Needed Capabilities Requiring Research

• Hierarchical Integration of Entire Supply & Delivery Chain

• Optimal End-to-End Dispatch under Uncertainties

• Dynamic Models of Generators and Loads

• Online Alarm Root-Cause Diagnostics

• Prevention of Cascading Outages, Safety Nets

• Fast System Restoration After Blackouts

ProtectionSCADA

Data Management

Network Management

Security

ChainIntegration

OutageManagement

Dynamic Models

End-to-End Dispatch

Restoration Protection


Layers For A Holistic Power Supply And Delivery Chain

Data monitoring, local analysis(Distributed at substations)

Alarm Management(at TO or regional control

centers)

Wide area coordination, dispatch, & control(at regional control centers)

PMUs

Relays

Sense Control

Dynamic models

Power Generationand Delivery System

and Loads

Power System Operation

PowerSystem

Planning• Normal operation• Emergency operation• System restoration


Wide Area Coordination at the Control Center

Dynamic modelsof generators and loads

and new types of resources

Optimal end-to-enddispatch under

uncertainty

Probabilisticcongestion forecasting

and predictive awareness

Online dynamicstability

simulation

Financialand risk

allocation

Effective wide area coordination,dispatch, and control

at regional control centers(normal operation)

Emergency Operation(e.g., islanding)

System Restoration


Hierarchical Monitoring And Analysis

Data monitoring, local analysis(Distributed at substations)

Alarm Management(at TO or regional control centers)

Wide area coordination, dispatch, control& restoration (at regional control centers)

PMUs

Relays

Sense Control

Generation

PMUs

Fuel availabil ity, curtailments

Fuel availability, curtailments

DistributionSystem

Intelligent Agents- Reconfigure distribution

- Roll info up to control centers

Loads(EE)

Dynamic models

PHEVs

AMI,Demand Response

(Prices to devices)

Dist Genand storage

Transmission


Source: California ISO

Tehachapi, California Wind Generation in April – 2005

0

100

200

300

400

500

600

700

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour

MW

Average

Each Day is a different color.

Day 29

Day 5 Day 26

Day 9

Could you predict the energy production for this wind park either day-ahead or 5 hours in advance?


Methods of Coping with Wind Uncertainty

• Short-Term– Better wind forecasting– Carry more operating and spinning

reserve to handle up and down ramps of wind output

– Rapid coordination with demand response and energy storage

• Long-Term– Build more energy storage, e.g.,

Compressed Air Energy Storage (CAES)

– Controllable demand response– Holistic planning of transmission,

generation and demand• Virtual Service Aggregator

0

50

100

150

200

250

300

350

Sep06 1

2:0

0

Sep06 1

4:2

4

Sep06 1

6:4

8

Sep06 1

9:1

2

Sep06 2

1:3

6

Sep07 0

0:0

0

Sep07 0

2:2

4

1-min MW

fcst 1

fcst 2

fcst 3

Potential wind curtailment

CAES


Potential Role of the Virtual Service Aggregator

TraditionalPower Plants

TraditionalPower Plants

RenewableResources

RenewableResources

EnergyStorage

EnergyStorage

TransmissionGrid

TransmissionGrid

Real RegionalControl Center

Real RegionalControl Center

VirtualService

Aggregator

Σ

VirtualService

Aggregator

Σ

End Usesand

DistributedResources

End Usesand

DistributedResources

FinancialSettlement ofNet Difference

Power Flow

FinancialTransaction


Alarm Management

Alarm Management

• Need to diagnose root-cause of alarm messages

• Need to link diagnosis to operator procedure

• Current EMS alarm management uses technologies of the 1970s

• Need to integrate all sources of data and messages, through a hierarchical approach


Why Accurate Load and Generator Models Are Needed?

• Inadequacy of current model data– Inaccurate voltage recovery

simulation after disturbances– Uncertainty about generator

reactive power capabilities• Implications

– Uncertainty about the stability margin of the power grid

– Unaware of real risk of cascading blackouts or voltage collapse, or

– Under utilization of available stability margin for greater economic benefits

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 20

0.2

0.4

0.6

0.8

1

Time (seconds)

Vol

tage

(pu

)

Hassayampa 500 kV

MeasuredSimulated H=0.3Simulated H=0.03

Simulated H=0.05Simulated H=0.1Simulated H=0.2Simulated H =0.5

Southern Co.’s GenVARRTM


Major Power System Disturbances

0

10

20

30

40

50

60

70

0 10 20 30 40 50 60

Duration in Hours

Lo

ad

Lo

st in

GW

1 - 2003 NE

2 - 1965 NE

3 - 1977 NYC

4 - 1982 WSCC 5 - 1996 WSCC

6 - 1996 WSCC

7 - 1998 MW

Restoration Objectives: ▪ Minimize Duration of Outages ▪ Minimized Unserved Loads ▪ Avoid Equipment Danage

Source: Mike Adibi, NSF/EPRI Workshop on Understanding and Preventing Cascading Failures in Power Systems, Oct 28, 2005.

Effective System Restoration Can Reduce The Societal Impact Of Widespread Blackouts

•Operators need online decision support for restoration strategies

•How can automation be used to improve system restoration?


Prevention of Cascading Outages – Safety Nets

• Application of SynchroPhasor Measurements for Controlled Separation, Load Shedding and Generation Rejection

– Controlled separation is an effective last resort to mitigate severe cascading failures

– Voltage Instability Load Shedding

– Online risk monitoring of potential cascading outages


EPRI’s Grid Operations and Planning Research

Situational

Awareness

Reliability

Assessment

Modeling & Standardization

Online Stability &Control

System

RestorationStable Generator

-90

0

90

180

270

58.00 58.50 59.00 59.50 60.00 60.50 61.00 61.50 62.00

Frequency (Hz)

An

gle

(D

eg

ree

)

System

Studies

Understanding, Predicting, and Preventing Cascaded Outages (Black Out)


Alarm Management

Most Needed Capabilities Requiring Research

• Hierarchical Integration of Entire Supply & Delivery Chain

• Optimal End-to-End Dispatch under Uncertainties

• Dynamic Models of Generators and Loads

• Online Alarm Root-Cause Diagnostics

• Prevention of Cascading Outages, Safety Nets

• Fast System Restoration After Blackouts

ProtectionSCADA

Data Management

Network Management

Security

ChainIntegration

OutageManagement

Dynamic Models

End-to-End Dispatch

Restoration Protection


NASPI (North America Synchro-Phasor Initiative)

• Training Materialshttp://www.naspi.org/resources/training/training.stm

• Work Group Meetingshttp://www.naspi.org/meetings/workgroup/workgroup.stm


Thank you