Smart Distribution Systems:
Communications Perspective
S. S. (Mani) Venkata
Alstom Grid and University of Washington (UW)
mani.venkata@alstom.com
venkata@ee.washington.edu
2011 SECON Workshop Panel Presentation
Salt Lake City, UT
June 27, 2011
Co-author: Sumit Roy, UW
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“Edison’s Grid” Today
 Simple concept


Robust; Effective
Not much changed in
the last century
Transmission
Line
Generatin
Plan
Substation
 Complex in execution

Thousands of
classical, central
power plants
 Web of transmission
lines (above 120-kV)
 More complex web of
distribution lines
(below 69-kV)
Distribution
System
End User
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Smart Grid: A Digital, InformationAge Grid
 Basic structure
– Today’s (Edison’s) grid is the starting point
– Applies information technology
– Much more information and control
 Power of Timely information
– Deregulation
– Infusion of new technologies
– More precise system design and operation
– Improved reliability, efficiency, safety, security and
cost
– Ability to meet customer needs
– More products and services
– Reduced emissions and environmental impact
3
What is in Store for the Future?
 The real world is full of uncertainties
 Many needs of the society are geographically
imbalanced
 Energy demand and supply unbalance will continue
to exist in the future
 Global population will increase by 30% to 8 billion in
the next 40 years
 How do we prepare to meet the challenges and
take advantage of the opportunities?
4/8/2015
© 2010 Copyright S. S.
Venkata
4
4
Global Issues of Concern (contd.)
 Ecology and environment protection is essential
– Global warming is one critical example
 Next to air and water, energy is the most important
need of the society
 How to achieve balance between all conflicting
forces?
 Seeking sustainable energy resources is the answer
without sacrificing air and water quality
4/8/2015
© 2010 Copyright S. S.
Venkata
5
5
Need for Reduced Political Barriers
 Governments should aim for reduced bureaucracy
 Regulators need to balance societal and utility
needs.
– Reduced time for approval for new projects
 Utilities have to balance their internal enterprise
management in the most efficient and effective
ways
4/8/2015
© 2010 Copyright S. S.
Venkata
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3277 Electric Distribution System Utilities
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Distribution Systems is neglected step child
Distribution System serves 131 Million Customers
3.1 Million miles of Distribution lines
Electrical infrastructure is ageing rapidly (?)
Total Revenue $256 billion / year
Average cost of retail energy sales $0.074 / kWh
Average cost of power generation $0.041 / kWh
Total cost of distribution losses $6.9 Billion / year
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Legacy System Deficiencies
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Little flexibility and intelligence
Outdated network
Unacceptable performance measures
Consumer cost of service issues
Environmental issues
Limited information from the electric
facilities.
 The visibility is only provided by
SCADA monitoring and control of
the distribution substations with little
or no telemetry or control of
distribution line devices.
4/8/2015
© 2010 Copyright S. S.
Venkata
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Why the Smart Grid Revolution?
‘‘
4/8/2015
Running today's digital society through
yesterday's grid is like running the Internet
through an old telephone switchboard
© 2010 Copyright S. S.
Venkata
9 Reid Detchon
’’
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Impetus for Smart Grid Development
 Deregulation (re-regulation?)
 Development of new technologies
 Protection of environment and ecology
 Meet customer needs and
 Birth of “Smart Grid” (Intelligent Grid)
4/8/2015
© 2010 Copyright S. S.
Venkata
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10
Optimal Performance Measures for Smart Grid
Development
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Customer Satisfaction
Efficiency
Reliability
Voltage and frequency regulation
Power Quality
Economy
Environment and ecology
Regulatory
Security (system and cyber)
Safety
4/8/2015
© 2010 Copyright S. S.
Venkata
11
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Smart Grid Components
 Broadband over
Power lines
— Provide for two-way
communications
 Monitors and smart
relays at substations
 Monitors at
transformers, circuit
breakers and
reclosers
 Bi-directional meters
with two-way
communication
Generating
Plant
Transmission Line
Substation
Distribution
System
End User
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An Integrated Energy System
 Incorporates entire energy pathway, from generation to customer
 High-speed, near real-time, two-way communications
 Sensors, solid-state controllers, switches, protective devices,
transformers, enabling rapid diagnosis and corrections
 Distributed Energy Resources (DER)
 Distributed Generation
 Energy Storage
 Demand Response
 Plug-in Electric Vehicles
13
Smart Grid Benefits
Demand Management
• Better demand control = reduced
generation reserve requirement
• Control demand toRenewables
match supply
Management
• Pricing based on real-time
• Shapemarket
load to generation
• Manage intermittency
Asset Management
• Maximize renewables
• Improve field efficiency
• Supply-based pricing
• Real-time asset status & control
• Expanded
reliability
Customer-Enabled
Management
• Extended
life control of electronic
• asset
Automatic
devices
• Real-time pricing
• New services and products
• Enable customer choice
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Smart Grid: Architectural View
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Smart Grid Comm. Standards
Domains
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T&D Wide-Area Networks
Name
Notes
Frame Relay
Packet-switched, no reliability guarantee
SONET
Campus or city backbones
WDM
Wavelength Division Multiplexing – follows SONET
Microwave
Proprietary, used in geographically difficult areas
Satellite
Various proprietary technologies, costly
Trunked Radio
Licensed, one broadcast channel, one return
Spread-Spectrum
Unlicensed frequencies, more efficient
IP Radio
Like trunked radio but with IP addressing
 Many of these are considered obsolete or
aging in the general IT world
 Still in common use in the power system
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T&D Substations
Name / No.
Description
Status
IEC 61850
Object models, self-describing, high-speed
relaying, process bus
Widespread in Europe,
beginning here
DNP3
Distributed Network Protocol
Most popular in NA
Modbus
Evolved from process automation
Close second
COMTRADE
Fault Capture file format
Widespread
PQDIF
Power Quality file format
In use
IEC 62351
Security for power systems
Recently released

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Automation common in transmission
Business case tough in distribution
Well-known problems and solutions
Moving to the next level
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Access Wide-Area Networks
Name
Notes
PSTN
Public Switched Telephone Network – dial-up, leased lines
DSL
Digital Subscriber Line - Telco IP-based home access
Cable
DOCSIS standard for coax IP-based home access
WiMAX
WiFi with a backbone, cellular-type coverage
Cellular
Various technologies e.g. GSM/GPRS or CDMA/EVDO
FTTH
Fiber to the Home. Passive Optical Networks (PONs)
PLC
Narrowband Power Line Carrier – the “old stuff”
Access BPL
Broadband over power line to the home
Paging
Various proprietary systems, POCSAG
 Used to reach the Collector or Substation
 Too expensive, too unreliable or too slow for actual
access to home
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Field Area Networks – Distribution
and AMI
 Offerings mostly proprietary
– Wireless mesh, licensed or unlicensed
– Power line carrier, narrowband or
broadband
– New standard activity just started in 2008
 Open standards not useful yet
Metering
Network
– Cellular, WiMAX, ADSL, Cable, FITL
Network
A
– Not economical or not reliable or both
– Mostly only reach the Collector level
 Interop solution: common upper layer
– Network layer preferred: IP suite
– Most don’t have bandwidth
 Application layer instead: ANSI C12.22
A
– Too flexible, not enough interoperability
– Need guidelines, profile from users
 More bandwidth the main solution!
A B
Metering
Network
Network
B
B
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Home Area Networks
Name
Number
Notes
Ethernet
IEEE 802.3
Substation LANs, usually fiber optic
WiFi
IEEE 802.11
Access by field tool, neighborhood AMI net
ZigBee
IEEE 802.15.4
Customer premises automation network
HomePlug
1.0, AV, BPL
Powerline comms, in and outside premises
6LowPAN
IEEE 802.15.4
The “approved” IPv6 wireless interface
OpenHAN
HAN SRS v1.042008
Power Industry requirements definition!
 ZigBee and HomePlug alliance
– Popular open specifications

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LONWorks, Insteon, Z-Wave, X10 – popular
proprietary networks
Challenges coming in Electric Vehicles
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October 2009
doc.: IEEE P2030-09-0110-00-0011
The Smart Grid Communications Physical Architecture
Submission
Page 6
Claudio Lima, Sonoma Innovation
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NIST’s System Architecture
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October 2009
doc.: IEEE P2030-09-0110-00-0011
Smart Grid Logical Communications Architecture
Submission
Page 7
Claudio Lima, Sonoma Innovation
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Power and Computing Infrastructure
Power Infrastructure
Data network Users
Distributed Computing Infrastructure
Central Generating
Station
Step-Up
Transformer
Control Center
Distribution
Substation
Gas
Turbine
Receiving
Station
Distribution
Substation
Recip
Engine
Distribution
Substation
Microturbine
Residential Data
Concentrator
Recip
Engine
Commercial
Fuel
cell
Photo
voltaics
Cogeneration
Batteries
Flywheel
Industrial
Commercial
Residential
Source: EPRI IntelliGridSM Project
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