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Smart-GridSmart-Grid
or the Micro-Grid?or the Micro-Grid?
Prof. Douglas C Hopkins, Ph.D.Dir. Electronic Power and Energy Research Laboratory
www.DCHopkins.Com
Prof. Mohammed Safiuddin, Ph.D.Dir. Power Conversion and Controls Laboratory
State University of New York at Buffalo
332 Bonner Hall
Buffalo, New York 14260-1900
An electronic design Webcast 27 April 2010
with additional material from our
UB Graduate Course
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COPYRIGHT PERMISSION
Some material contained in this document may be covered by one or
more copyright restrictions and are noted to the authorsユ best abilities.
Those who have attended an IEEE Seminar presented by Dr. Douglas C.
Hopkins are granted sole use as an extension of the presented
seminar.
Others are granted permission for sole use for their personaladvancement, but cannot extend to included information copyrighted by
others.
Please respect intellectual property restrictions.
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Power CurriculumPower Curriculum at theat the
University at BuffaloUniversity at Buffalo
A special Masters of Engineering degree is offered at
the University at Buffalo directed to the practicing utility
engineer or electrical power engineer.
Following are the courses offered in the sequence.
For further information contact
Prof M. Safiuddin <[email protected]>
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UB UB MEngMEng* Courses* CoursesEAS 521 Y Principles of Engineering Management I C. Chang
Basic engineering management functions of planning, organizing, leading, and controlling, as
applied to project, team, knowledge, group/department and global settings, including
discussion of the strengths and weaknesses of engineers as managers, and the engineering
management challenges in the new economy. Emphasis is placed on the integration of
engineering technologies and management. Students are to understand/practice the basic
functions in engineering management, the roles and perspectives of engineering managers,
and selected skills required to become effective engineering managers in the new millennium.
Text: Notes
EE 582 Y Power Systems Engineering I. D. C. Hopkins
Review of fundamentals of three-phase power systems, power circuit analysis, characterization
and modeling of power system components, such as transformers and transmission lines, for
study of power flow and system operation with extension to advanced power system
components.
Text: Power Systems Analysis & Design; Glover & Sarma - Chapters 2-5 & 8
EE 587 Y Special Topics in Electrical Power Distribution M. Safiuddin
System planning and design, surge protection, system protection, system power factor, power
system pollution, and system interfaces.
Text: ANSI/IEEE Stnd. 141-1993 [The Red Book], IEEE Press
*Synchronous on-line distance learning, accredited for internationally delivery
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UB UB MEngMEng* Courses * Courses ((concon’’dd))
EE 583 Z Power Systems Engineering II J. Zirnheld
Investigate transmission line characteristics of aerial and underground lines including
development of their symmetrical component sequence impedances, Steady-state
performance of systems including methods of network solutions.
Text: Power System Analysis & Design; Glover & Sarma - Chapters 6-13 (except 8)
EE 641Y Power System Protection-Theory & Applications Ilya Grinberg
Power Systems Relay Protection. Principles of relay techniques (classical and solid state), current
and potential transformers and their application in relaying technique, over-current, differential,
impedance, frequency, overvoltage and undervoltage relays, relay protection of overhead and
underground power lines, generators, transformers, motors, and buses.
Text: Protective Relaying Theory and Applications, edited by W.A. Elmore, Marcel Dekker, 2nd
Rev & Ex Edition, Sept 2003.
EE 540Y Static Power Conversion for Power Systems D. C. Hopkins
Principles of operation of static compensators and basic configurations; series, shunt and shunt-
series; flexible ac transmission systems (FACTS); line and self commutated controllers,
configurations and control aspects; applications to power distribution systems; performance
evaluation and practical applications of static compensators.
Text: Understanding FACTS- Concepts & Technology of Flexible AC Transm. Syst.; Hingorani
and Gugyi
*Synchronous on-line distance learning, accredited for internationally delivery
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UB UB MEngMEng* Courses * Courses ((concon’’dd))
EE 598- Contemporary Issues in Electrical Power Industry- [Independent Study] M.
Safiuddin
Energy Management Issues - Supply/Demand/Conservation
Electrical Power System Quality and Reliability
Industry Restructuring - Pains & Gains- Who is really in charge?
Electrical Power Generation and Global Warming; Cost Effectiveness Issues
EE 606Y- Distributed Generation: M. Safiuddin
Historical perspective of electric power industry, fundamentals of distributed generation,
economics of distributed resources, Micro-turbines, fuel cells, solar and wind power systems.
Text: Renewable and Efficient Power Systems; Gilbert M. Masters; IEEE Press;
*Synchronous on-line distance learning, accredited for internationally delivery
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Topics are introduced from an electronics processing / power
electronics v. power systems perspective.
Seminar ObjectiveSeminar ObjectiveMoving the Electronics Designer into Power Engineering
(An insurmountable Task?)
Electronics
Designers
Power Electronics
Power
Engineering
Communications
If you’re not processing
information, you must be
processing power
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OUR CHALLENGEOUR CHALLENGE
- LEGACY DOMANANCE -- LEGACY DOMANANCE -
All Smart Grid initiatives will need to integrate with the
Legacy Systems.
Utilities have tremendous precedent that has been
maintained because of the“deep pockets” they offer
when good things might go wrong.
How to overcome the “Legacy” hurdle?
STANDARDS
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Standards - A Critical ElementStandards - A Critical Element
NIST Special Publication 1108
NIST Framework and Roadmap for
Smart Grid Interoperability
Standards, Release 1.0
Office of the National Coordinator for Smart
Grid Interoperability
January 2010
www.nist.gov/public_affairs/releases/
smartgrid_interoperability_final.pdf
“…Deployment of various Smart Grid elements, including smart
sensors on distribution lines, smart meters in homes, and widely
dispersed sources of renewable energy, is already underway…”
http://www.nist.gov/smartgrid/
“Without standards, there is the potential for technologies
developed or implemented with sizable public and private
investments to become obsolete prematurely or to be
implemented without measures necessary to ensure security.”
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Why NIST FrameworkWhy NIST Framework
There is an urgent need to establish protocols and standards
for the Smart Grid.
Deployment of various Smart Grid elements, including smart sensors on
distribution lines, smart meters in homes, and widely dispersed sources
of renewable energy, is already underway...
Without standards, there is the potential for technologies developed or
implemented with sizable public and private investments to become
obsolete prematurely or to be implemented without measures
necessary to ensure security.
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Lost inLost in WHAT IS THE SMART GRID?WHAT IS THE SMART GRID?
1.4 Content Overview - Areas worth reading1.4 Content Overview - Areas worth reading
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Primary PlayersPrimary Players
The market place will
be a primary driver
and should not be
overlooked
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Smart Grid Information NetworksSmart Grid Information Networks
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Lost inLost in WHAT IS THE SMART GRID?WHAT IS THE SMART GRID?
NIST-1.4 Content Overview -NIST-1.4 Content Overview -
Areas worth readingAreas worth reading
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NIST-1.4 Content OverviewNIST-1.4 Content Overview
Chapter 2, “Smart Grid Vision”
Chapter 3, “Conceptual Reference Model”
• presents a set of views (diagrams) and descriptions that are the basis for
discussing the characteristics, uses, behavior, interfaces, requirements, and
standards of the Smart Grid.
Chapter 4, “Standards Identified for Implementation”
• presents and describes existing standards and emerging specifications
applicable to the Smart Grid. It includes descriptions of proposed selection
criteria, a general overview of the standards identified by stakeholders in the
NIST- coordinated process, and a discussion of their relevance to Smart Grid
interoperability requirements.
Chapter 5 describes sixteen "Priority Action Plans”
Chapter 6, “Cyber Security Risk Management Framework and Strategy”
Chapter 7, “Next Steps”
Excellent orientation to
the Smart Grid Thrust
A “must follow”
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What is important about the NIST REPORT andWhat is important about the NIST REPORT and
what is important for us to follow?what is important for us to follow?NIST-1.3.2 Applications and RequirementsNIST-1.3.2 Applications and Requirements
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NIST-1.3.2 Apps and NIST-1.3.2 Apps and ReqReq’’ss
1.3.2 Applications and Requirements: Eight Priority Areas
To prioritize its work, NIST chose to focus on six key functionalities plus
Cyber Security and Network Communications
1. Wide-area situational awareness
2. Demand response
3. Consumer energy efficiency
4. Cyber security
5. Network communications
6. Advanced metering infrastructure (AMI)
7. Distribution grid management
8. Energy storage
9. Electric transportation
These are the AREAS toread about.
Where does your
expertise lie?
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NISTNIST Report provides a comprehensiveReport provides a comprehensive
SUMMARY of RELEVANT STANDARDSSUMMARY of RELEVANT STANDARDS
for us to followfor us to follow
Following are short descriptions of the
standards of interest.
These are not discussed here, but included for your
later reading.
Speed through the
next several slides!
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Cited Standards of interestCited Standards of interest4 DNP3 - This standard is used for substation and feeder device
automation as well as for communications between control centers andsubstations.
8 IEEE C37.118 - Synchrophasor Protocol (synchrophasor):
This standard defines phasor measurement unit (PMU) performancespecifications and communications.
9 IEEE 1547 Suite - This family of standards defines physical andelectrical interconnections between utility and distributed generation(DG) and storage. [http://grouper.ieee.org/groups/scc21/dr_shared/]
19 IEEE P2030 Draft Guide for Smart Grid Interoperability of EnergyTechnology and Information Technology Operation with Electric PowerSystem (EPS) and End-Use Applications and Loads.
• Standards, guidelines to be developed by IEEE P2030 Smart GridInteroperability.
23 IEEE C37.2-2008 - IEEE Standard Electric Power System DeviceFunction Numbers - Protective circuit device modeling numberingscheme for various switchgear.
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Cited Standards of interestCited Standards of interest24 IEEE C37.111-199 - IEEE Standard Common Format for Transient
Data Exchange (COMTRADE) for Power Systems (COMTRADE) -Applications using transient data from power system monitoring,including power system relays, power quality monitoring field andworkstation equipment.
26 IEEE 1159.3 - Recommended Practice for the Transfer of PowerQuality Data - Applications using of power quality data.
27 IEEE 1379-2000 Substation Automation - Intelligent ElectronicDevices (IEDs) and remote terminal units (RTUs) in electric utilitysubstations.
38 SAE J1772 - Electrical Connector between PEV and EVSE - Electricalconnector between Plug-in Electric Vehicles (PEVs) and ElectricVehicle Supply Equipment (EVSE)
40 SAE J2847/1-3 - Communications for PEV Interactions; J2847/1Communication between Plug-in Vehicles and the Utility Grid; J2847/2Communication between Plug-in Vehicles and the Supply Equipment(EVSE); J2847/3 Communication between Plug-in Vehicles and theUtility Grid for Reverse Power Flow.
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Other NIST Standards TopicsOther NIST Standards Topics
5.14 Energy Storage Interconnection Guidelines (PAP 07)
What Energy storage is required to accommodate the increasing
penetration of intermittent renewable energy resources and to improve
Electric Power System (EPS) performance. Consistent, uniformly
applied interconnection and information model standards, supported by
implementation guidelines, are required for energy storage devices
(ES), power electronics interconnection of distributed energy resources
(DER), hybrid generation-storage systems (ES- DER), and plug-in
electric vehicles (PEV) used as storage.
Why Due to the initial limited applications of the use of power electronics
for grid interconnection of ES and DER, there are few standards that
exist to capture how it could or should be utilized as a grid-integrated
operational asset on the legacy grid and Smart Grid. For example, no
standards address grid-specific aspects of aggregating large or small
mobile energy storage units, such as Plug-in Electric Vehicles
(PEVs)….
http://collaborate.nist.gov/twiki-sggrid/bin/view/SmartGrid/PAP07Storage.
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Other NIST StandardsOther NIST Standards5.15 Interoperability Standards to Support Plug-in Electric Vehicles (PAP
11) Interoperability standards that will define data standards to enable the
charging of plug-in electric vehicles (PEVs) will support the adoption of PEVs
and related benefits. Standards are anticipated to be available by the end of
2010.
• [Task 6: Coordinate standards activities for electrical interconnection and safety
standards for chargers and discharging, as well as a weights and standards
certification and seal for charging/discharging. - UL, SAE, IEEE, NEC,NEMA]
http://collaborate.nist.gov/twiki- sggrid/bin/view/SmartGrid/PAP11PEV
7.3 Other Issues to be Addressed This section describes other major
standards-related issues and barriers impacting standardization efforts and
progress toward a fully interoperable Smart Grid.
• 7.3.1 Electromagnetic Disturbances Standards for the Smart Grid should consider
electromagnetic disturbances, including severe solar (geomagnetic) storm risks and
Intentional Electromagnetic Interference (IEMI) threats such as High-Altitude
Electromagnetic Pulse (HEMP).
• 7.3.2 Electromagnetic Interference The burgeoning of communications
technologies, both wired and wireless, used by Smart Grid equipment can lead to
EMC interference, which represents another standards issue requiring study.
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Other Standards to read aboutOther Standards to read about……
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SAE J2293, IEEE P2030 & 1547SAE J2293, IEEE P2030 & 1547
SAE J2293
Energy Transfer
System for Electric
Vehicles
IEEE 1547
Interconnection
Standards
IEEE P2030
Smart Grid
Interoperability
Standards
Electrical -
functional
interconnection
between electric
grid and electric
vehicle (two-way
power flow)
Communication,
control and
information (V2G)
Energy
transfer
system for
electric
vehicles
P2030 Title: “Guide for Smart Grid Interoperability of Energy Technology and Information
Technology Operation with the Elect Pwr Syst (EPS) and End-Use Applications and Loads”
v. Interconnection
New-P1809 ElectricNew-P1809 Electric
TransportationTransportation
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END - Standards (YEA!)END - Standards (YEA!)
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WhatWhat is the Smart Grid?is the Smart Grid?
What is the Micro-Grid?What is the Micro-Grid?
[EPRI 2006]: “The term ‘Smart Grid’ refers to a modernization of the
electricity delivery system so it
monitors, protects and automatically optimizes the operation of its
interconnected elements—
from the central and distributed generator through the high-voltage
network and
distribution system, to industrial users and building automation systems,
to energy storage installations and to end-use consumers…”
Our discussion is from Sub-Transmission to the Meter
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Structure of Interest in a NutshellStructure of Interest in a Nutshell
Picture from: http://www.peco.com/pecores/customer_service/the_electric_system.htm
(1) & (2): Generation step-up to Transmission !115kV
Flow is regulated by ISOs (Independent System Operators)
(3) Distribution is "12kV
(12.47kV or 7,200V L-N)
(3) thru (4)
ARE MAIN FOCUS
(4) Local distribution is "4.8kV
down to 120V (4,160V or
2400 L-N)
Distribution transformer is on the pole;
Substation transformer is on the ground in the Distribution Substation/Switch Yard
Voltage RangesVoltage Ranges(ANSI C84.1 Standard)(ANSI C84.1 Standard)
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“Traditionally,” system stability is
part of transmission
Major resource for information is
the IEEE “Red Book”
“Local distribution” is considered
240V/480V
Focus on "12kV system, know
nuances of requirements and how
PElect can include protection.
Distribution
Substation
Sub-Transmission
Substation
Transmission
!115kV
5 to 20 MVA
(or higher)
See “Red Book”
12kV
Industrial
Loads
Alternative
Energy
Sources
e.g. 4800k
(in NY)
Structure of Interest in a NutshellStructure of Interest in a Nutshell
Breaker protects
transformer
Breaker protects
cabling
Some disconnects
can open under load
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Voltage RangesVoltage Ranges (ANSI C84.1 Standard) (ANSI C84.1 Standard)
Are
as o
f in
tere
st
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The UB Micro-Grid ProjectThe UB Micro-Grid Project
The Intelligent Substation -
A proposed test bed at the
University at Buffalo
(Consortium members are being sought)
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Who are the Players?Who are the Players?
DER-Distributed Energy Resources
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UB Micro-GridUB Micro-Grid
•Campus-integrated
•34.5kV dual feeds
•Multiple dist voltages
•Multiple renewables
• (50kW levels)•AC & DC dist
•Circular pwr flow
•Advanced controls
• (Neural network ctrl)
•Environ. testing
Technology Areas:Technology Areas:
1. Distributed Generation – Green Power Conversion
2. Automation & Control – Artificial Neural Networks
3. Intelligent Sensors & Networks – Wired & Wireless
4. System Protection – AC/DC and FACTS systems
5. Energy Storage – Electrochemical, Electromechanical
6. Residential EMS [Energy Management Systems]7. Interoperability between the Old & the New
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Simple fundamentals make you sound likeSimple fundamentals make you sound like
you know what you are talking about*.you know what you are talking about*.
The Lingo
The Acronyms
The Demystification
* i.e. How to sound like an expert.
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Power conversion (e.g. MVDC)
What power control is needed?What power control is needed?
Stability
Quality control
Directional routing
Power flow control
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Transmission Line ModelsTransmission Line Models
Parameters of distributed inductance, capacitance and resistance
precisely define the “overhead” transmission line. However, for short
lines a simpler model can be used.
Three models estimate the transmission line
Short Lines < 50 mi. – only a series impedance
50< Medium Lines < 250mi – uses singular lumped parameters
250mi.< Long Lines – uses distributed parameters
Short lines are typically represented by inductance only. Resistance can
be lumped with the load.
Depending on system cost, reliability and location “CABLING” is used.
[Cabling is not included in this seminar]
Distribution Lines
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General power flow - simple lineGeneral power flow - simple line
Eg / ! VB / 0
jXB
+ I -
!
If " # $Eg %$VB Find : Power to control
!
r I = Eg"# $VB"0( ) jX B( )
!
Therefore : SB = VB Eg sin(" )+ jVB Eg cos(" )# jVB2[ ] X B
P jQ
!
(At the Receiving End) , SB = PB + jQB = VB • I *
Focus on Real
Power (P), since
that is the monetary
profit being sought.
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Changing REAL power flow?Changing REAL power flow?
Eg / ! VB / 0
jXB
+ I -
!
P =EgVB
X B
sin(" )#
$ % %
&
' ( (
• Influence the magnitude of the source bus voltage.
• Influence the line reactance.
• Influence the magnitude of the load bus voltage.
Pow
er[W
]
![rad]
• Influence the angle, !, of the load.
(! = / Eg - / VB )
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General placementGeneral placement
Series controller
Inter-tie controller
Shunt controller
DCw/ storage
DC
dc link
Unified series-shunt controller
(w, w/o storage)
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Symmetrical ComponentsSymmetrical Components
- CONCEPT ONLY-- CONCEPT ONLY-
An easy method to understand unbalanced systems
Characteristics:
System must be linear for superposition of Components
All waves in Symmetrical Components are single-frequency
sinusoids
Symmetrical Components can be combined with Fourier
Analysis to understand harmonic effects and wave
distortion.
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Symmetrical ComponentsSymmetrical Components
Consider a set of three general phasors each having a
unique magnitude and phase. These can be mapped
onto a set of symmetrical phasors, not all uniquely
defined.
Re
Im120°
120° 120°
Voltage of Current
Phasor Phasors & Symmetrical Components
Positive
sequence
Negative
sequence
Zero
sequence
a
a
b
c
b
c
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Sequence Set RepresentationSequence Set Representation
Any arbitrary set of three phasors, say Ia, Ib, Ic, and each having a
unique magnitude and phase (but all with same frequency) can be
represented as a sum of the three sequence sets
!
Ia
= Ia
0+ I
a
++ I
a
"
!
Ib
= Ib
0+ I
b
++ I
b
"
!
Ic
= Ic
0+ I
c
++ I
c
"
The symmetrical components are:
!
I a+
,I b+
,I c+ are positive sequence set
I a"
,I b"
,I c" are negative sequence set
I a0
,I b0
,I c0 are zero sequence set
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““Per UnitPer Unit”” System of Calculations System of Calculations
Makes transformers disappear.
Not easy to use at first.
A very common nomenclature used in power systems.
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Three-Phase Per Unit SystemThree-Phase Per Unit System
1. Pick 3-ph bases for system: use L-L voltage,VB,LL, and complex
power, SB,3ø [VA]. (Often nameplate transformer data.)
2. Reflect the voltage base through the transformers, i.e. different
voltage bases – VB, all L-L. (Power passes directly.)
3. Calculate the impedance base
Note - same impedance base as single phase!
Procedure is similar to 1-ph except we use a 3-ph VA base, and use
Line-to-Line voltage base. Always assume a balanced system.
2 2 2, , ,
3 1 1
( 3 )
3
B LL B LN B LN
B
B B B
V V VZ
S S S! ! !
= = =
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Three Phase Per Unit, cont'dThree Phase Per Unit, cont'd
4. Calculate the current base, IB
Same current basis as with single phase.
5. Convert actual values to per unit
All discussions would ensue in “per unit” terminology.
3 1 13 1B B
, , ,
3I I
3 3 3
B B B
B LL B LN B LN
S S S
V V V
! ! !! != = = =
Not easy? You’re right.
But, it makes big systems easier to understand.
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HarmonicsHarmonics
- CONCEPT ONLY-- CONCEPT ONLY-
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The BasicsThe Basics
Any physically realizable periodic function, f(t) = f(t+T), (for period T) can
be written as a sum of sinusoids:
where the sum is taken over n=1 to infinity, ! = 2"/T,
However, there is easier view for conceptualization
!
f t( ) = a0 + an cos nwt( ) + bn sin nwt( )[ ]n=1
"
#
!
a0 : Average of f t( ) = f t( )
!
a0 =1
Tf t( )dt
"
" +T
#
!
an =2
Tf t( ) cos nwt( )dt
"
" +T
#
!
bn =2
Tf t( ) sin nwt( )dt
"
" +T
#
!
" = 2# $ freq , freq = 1T
Time varying sinusoids displaced by 90˚
Magnitudes for each sinusoid
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Each cosine term, cn cos(n!t + "n), is called a Fourier Component or a
Harmonic of the function f(t) with “n” harmonics.
Polar FormPolar Form
We can also write
The term c1 cos(!t + "1) is of “fundamental” frequency.
In power, we seek a single desired frequency
!
f t( ) = cn cos n"t +#n( )n=0
$
%"= "
n
n
na
b1tan#
+=
==
nnnbac
ac
22
000 0#,
Of most interest
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Harmonics in CircuitsHarmonics in Circuits
A non-sinusoidal source can be decomposed into Fourier Components
Each component can be individually applied to the same “LINEAR”
circuit, and through “superposition,” the effects of each component
individually evaluated.
Harmonic Superposition is a major concept for switching circuits
v(t)
v1(t)
v2(t)
v0
XL(f) XC(f)
v3(t)
http://www.ipes.ethz.ch/
http://www.ipes.ethz.ch/ipes/pfc/e_fourier.html
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!
pavg ="
2#vnim cos( n"t +$n )cos( m"t +%m )dt
0
2 #"&
m=0
'
()
*
+ +
,
-
.
. n=0
'
(
What about Harmonic Power?What about Harmonic Power?
!
v t( ) = vn
cos n"t +#n( )$
!
i t( ) = im
cos m"t +#m( )$
Assume a voltage
and a current
with the same base frequency !.
+
"
v(t)
i(t)
ENERGY
!
p t( ) = v t( ) " i t( )
!
= vn cos()"[ ] im cos()"[ ]
!
pavg ="
2#$ $[ ]
0
2#"% dt
What is the “power” flow in the circuit?
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!
pavg = 1 2 4 4 3 4 4 m=0
"
#$
%
& &
'
(
) )
n=0
"
#
!
Pavg = v0i0 +vnin
2 2cos("n #$n )
n=1
%
& = VnRMS I n
RMS cos("n #$n )
n=0
%
&
Average PowerAverage Power
IMPORTANT: ONLY “same-frequency” harmonics yield REAL power.
Cross-frequency harmonics contribute REACTIVE power along with
reactive components.
!
"
2#vnim cos( n"t +$n )cos( m"t +%m )dt
0
2#"&
!
"
2#( )dt
0
2#"$ =
0 , m % n
vnim cos(&n '(m )
2, n = m % 0
vnim , n = m = 0
)
* +
, +
CRITICAL
TAKE-AWAY!
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Harmonic DistortionHarmonic Distortion
DISTORATION - If you only need a single frequency
out, such as zero frequency, then what are the other
frequencies doing for you?
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Harmonics Harmonics w/ w/ Duty CycleDuty Cyclevariationvariation
1
0
DT
t0
t0+T
f(t)
!
f t( ) =1, ...
0 , ...
" # $
!
a0 =1
Tf ( t )dt
t0
T + t0
" =DT
T= D
!
an =2
Tf ( t ) cos( n"t )dt
t0
T + t0
# = ...
!
OR cn =2
"
sin( n"D )
n, n # 0
Fourier series of “generic” f(t)
!
f t( ) = D +2
"
sin n"D( )n
cos n#t $%n( )n=1
&
'
!
"n
= n#t0
Harmonics of a Rectangular Signal with Duty Cycle(http://www.ipes.ethz.ch/ipes/signalHarmo/e_harmo.html)
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Distortion is Fundamental toDistortion is Fundamental to
SwitchingSwitchingThere will always be unwanted terms. A switching converter does
not produce perfect waveforms (ac or dc).
How much of the signal is harmonic?
Total harmonic distortion (THD) measures the distortion content as
a fraction of the fundamental.
!
THD =
cn
2
n= 2
"
#
c1
2
!
IRMS
=1
2c
n
2
n=1
"
# $ THD =
IRMS
2 % IRMS
2
n=1
IRMS
2
n=1
To use the RMS value:
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Case StudyCase Study
AC v. DC for rural power
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Objectives:
Compares two methods of transmitting power to isolated
load:
Method 1: Transmits the available single-phase power to a motor
drive inverter.
Method 2: Converts 3-Phase AC to DC and transmits it to the same
motor drive.
My-T Acres Farm Project, Batavia, NY -My-T Acres Farm Project, Batavia, NY -by Dr. Mohammed Safiuddinby Dr. Mohammed Safiuddin
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500,000V !!!
120V
Transmission of 3-phase to isolated loads is expensive.
UNICO
Drive
Instead, Single-phase transmission would be more economical
BackgroundBackground
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1-Ph v. DC for point-of-load VSD1-Ph v. DC for point-of-load VSD
DC transmission
1-Phase AC transmission
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System Efficiency W/W
0
10
20
30
40
50
60
1008 1107 1207 1308 1507 1607
Speed (RPM)
Eff
icie
nc
y (
%)
AC LINK
DC LINK
System Efficiency W/VA
0
0.1
0.2
0.3
0.4
0.5
0.6
1008 1107 1207 1308 1507 1607
Speed (RPM)
Ra
tio
(P
-ou
t/V
A-i
n)
AC LINK
DC LINK
ComparisonComparison
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System Current THD
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
1008 1107 1207 1308 1507 1607
Speed (RPM)
TH
D (
%)
AC LINK
DC LINK
System Performance - THDSystem Performance - THD
Both DC and 1-ph AC distribution
are more cost effective than the
3-ph for isolated loads (limited by
the load values).
DC power link offers several
advantages over AC link:
• More efficient
• Allows lower components ratings
• Lower harmonic distortions on the
grid supply.
• Better power factor
• Can be used to supply large
loads.
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Changing REAL power flow?Changing REAL power flow?
Eg / ! VB / 0
jXB
+ I -
!
P =EgVB
X B
sin(" )#
$ % %
&
' ( (
• Influence the magnitude of the source bus voltage.
• Influence the line reactance.
• Influence the magnitude of the load bus voltage.
Pow
er[W
]
![rad]
• Influence the angle, !, of the load.
(! = / Eg - / VB )
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END general presentation for:END general presentation for:
Smart-GridSmart-Grid
or or Smart Micro-Grid?Smart Micro-Grid?
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APPENDIX - A FACTS/FACDSAPPENDIX - A FACTS/FACDS
Extra material on
FACTS - Flexible AC Transmission Systems
FACDS - Flexible AC Distribution Systems
(Excerpt from EE 540 Univ. at Buffalo)
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APPENDIX - AAPPENDIX - A
Electric Power Distribution andElectric Power Distribution and
Utilization StandardsUtilization Standards
Primary information comes from the IEEE Color Books
Distribution Topics are primarily
from the “Red Book”
ANSI/IEEE - Std. 141-1993
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The IEEE Color BooksThe IEEE Color Books
IEEE Std 141-1993: Recommended Practices for Electric Power
Distribution for Industrial Plants [RED]
IEEE Std 142-1991: Recommended Practice for Grounding of Industrial
and Commercial Power Systems [GREEN]
IEEE Std 241-1990: Recommended Practice for Power Systems in
Commercial Buildings [GRAY]
IEEE Std 242-1986: Recommended Practice for Protection and
Coordination of Industrial and Commercial Power Systems [BUFF]
IEEE Std 399-1990: Recommended Practice for Industrial and
Commercial Power System Analysis [BROWN]
IEEE Std 446-1987: Recommended Practice for Emergency & Standby
Power Systems for Industrial & Commercial Applications [ORANGE]
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IEEE Std 493-1990IEEE Std 493-1990: Recommended Practices for the Design of Reliable
Industrial & Commercial Power Systems [GOLD][GOLD]
IEEE Std 602-1986IEEE Std 602-1986: Recommended Practices for Electric Systems in
Healthcare Facilities [WHITE][WHITE]
IEEE Std 739-1984: Recommended Practices for Energy Conservation
and Cost Effective Planning in Industrial Facilities [BRONZE]
IEEE Std 1100-1992: Recommended Practices for Powering and
Grounding Sensitive Electronic Equipment [EMERALD]
The IEEE Color BooksThe IEEE Color Books
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NATIONAL STANDARDSNATIONAL STANDARDS
USA
ANSI- American National Standards Institute.
NIST- National Institute of Standards & Technology
ASTM- American Society for Testing & Materials.
EEI- Edison Electric Institute [Trade Assn. of Private Utilities].
EPRI- Electric Power Research Institute.
IEEE- Institute of Electrical & Electronics Engineers.
Mil.- Military – Department of Defense.
NEMA- National Electrical Manufacturers Association.
NFPA- National Fire Protection Association NEC
OSHA- Occupational Safety & Health Administration
UL- Underwriters Laboratories, Inc. [Safety Standards].
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INTERNATIONAL STANDARDSINTERNATIONAL STANDARDS
CANADA
CSA- Canadian Standards Association.
GERMANY
VDE- Verbandef Deutscher Elektrotechniker.
INTERNATIONAL (Headquarters- Geneva, Switzerland).
IEC- International Electrotechnical Commission
ISO- International Standards Organization.
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Placement of Transformers & Breakers-Placement of Transformers & Breakers-Understanding System-LevelUnderstanding System-Level Deployment ProblemsDeployment Problems
Solid State Transformers (SSTs) and Solid State Circuit
Breakers* (SSCBs) will need to co-exist with magnetic
transformers and electromechanical breakers
Legacy systems must be understood and included in
the early phase of system planning and part of the
equipment design process when developing new
apparatus.
*see next page
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SSCB v. SSPCSSCB v. SSPC
The “Solid State Circuit Breaker” (SSCB) is typically considered to have a
simple open and closing function when activated, and can open under
fault.
The “Solid State Power Controller” (SSPC) is typically considered to have
included current sensing, and fault current profiling including possible
current limiting. SSPCs are not typically associated with power
distribution because of the lower power levels of operation.
In this seminar the SSCB will include reference to SSPCs also.
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Placement in Simple RadialPlacement in Simple Radial
SystemSystemTransformer
• Has predicable source as do the circuit breakers
Breakers
• The right side breakers are typically thought to be molded case, self
contained breakers.
• The left side breaker is directly controlled as part of the protection scheme
Simple RADIAL System
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Placement in Simple Ring BusPlacement in Simple Ring Bus
SystemSystem
Ring Bus System (v. Radial) - Found in denser load areas
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Placement in SelectivePlacement in Selective SystemSystem
Primary Selective Radial System
Transformers
• Fed from either feeder, but
with predictable load
Breakers (no special issues)
Secondary Selective Radial Syst.
Transformers (no special issues)
Breakers (no special issues)
Protecting
Xfrmr
Protecting
Cabling
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Primary Loop Radial System -• Similar to Primary Selective Radial System
Placement in SelectivePlacement in Selective SystemSystem((concon’’dd))
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Load Expansion AlternativesLoad Expansion Alternatives
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Load Expansion AlternativesLoad Expansion Alternatives((concon’’dd))
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End - Thank youEnd - Thank you
Prof. Douglas C Hopkins, Ph.D.Dir. Electronic Power and Energy Research Laboratory
www.DCHopkins.Com
State University of New York at Buffalo
332 Bonner Hall
Buffalo, New York 14260-1900