Smart-Grid or the Micro-Grid?

www.electronicdesign.com © 2010 D. C. Hopkinswww.DCHopkins.Com

Smart-GridSmart-Grid

or the Micro-Grid?or the Micro-Grid?

Prof. Douglas C Hopkins, Ph.D.Dir. Electronic Power and Energy Research Laboratory

[email protected]

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


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.


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]>


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


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



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;



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


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


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.”


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.


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


Primary PlayersPrimary Players

The market place will

be a primary driver

and should not be

overlooked


Smart Grid Information NetworksSmart Grid Information Networks


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


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”


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


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?


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!


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.


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.


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.


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.


Other Standards to read aboutOther Standards to read about……


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


END - Standards (YEA!)END - Standards (YEA!)


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


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)


“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


Voltage RangesVoltage Ranges (ANSI C84.1 Standard) (ANSI C84.1 Standard)

Are

as o

f in

tere

st


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)

www.electronicdesign.com © 2010 D. C. Hopkinswww.DCHopkins.Com!"

Who are the Players?Who are the Players?

DER-Distributed Energy Resources


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


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.


Power conversion (e.g. MVDC)

What power control is needed?What power control is needed?

Stability

Quality control

Directional routing

Power flow control


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


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.


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 )


General placementGeneral placement

Series controller

Inter-tie controller

Shunt controller

DCw/ storage

DC

dc link

Unified series-shunt controller

(w, w/o storage)


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.


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


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


““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.


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! ! !

= = =


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.


HarmonicsHarmonics

- CONCEPT ONLY-- CONCEPT ONLY-


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


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


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


!

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?


!

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!


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?


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)


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:


Case StudyCase Study

AC v. DC for rural power


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


500,000V !!!

120V

Transmission of 3-phase to isolated loads is expensive.

UNICO

Drive

Instead, Single-phase transmission would be more economical

BackgroundBackground


1-Ph v. DC for point-of-load VSD1-Ph v. DC for point-of-load VSD

DC transmission

1-Phase AC transmission


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


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.


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 )


END general presentation for:END general presentation for:

Smart-GridSmart-Grid

or or Smart Micro-Grid?Smart Micro-Grid?


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)


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


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]


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


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].


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.


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


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.


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


Placement in Simple Ring BusPlacement in Simple Ring Bus

SystemSystem

Ring Bus System (v. Radial) - Found in denser load areas


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


Primary Loop Radial System -• Similar to Primary Selective Radial System

Placement in SelectivePlacement in Selective SystemSystem((concon’’dd))


Load Expansion AlternativesLoad Expansion Alternatives


Load Expansion AlternativesLoad Expansion Alternatives((concon’’dd))


End - Thank youEnd - Thank you

Prof. Douglas C Hopkins, Ph.D.Dir. Electronic Power and Energy Research Laboratory

[email protected]

www.DCHopkins.Com

State University of New York at Buffalo

332 Bonner Hall

Buffalo, New York 14260-1900

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