Power Electronics in a Smart-Grid Distribution System (pdf)

APEC’10, Palm Springs, CA © 2010, D. C. [email protected]

Power Electronics in a Smart-GridPower Electronics in a Smart-Grid

Distribution SystemDistribution System

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

+01-716-645-3115


COPYRIGHT PERMISSION

Some material contained in this document may be covered by

one or more copyright restrictions and are noted to the

authors’ 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 personal

advancement, but cannot extend to included information

copyrighted by others.

Please respect intellectual property restrictions.


OutlineOutline

Introduction

• Course Admin

• Credentials

• Course Objective

UB Degree and Courses

“Smart Grid” Topical Discussion

System Structure of Interest

Background - ‘Transmission

System’ and FACTS

Technical Review

• Concept development

• 3-ph, Symmetry, Harmonics

• Power Control

• Power Flow

The Power Distribution System -

Identifying Critical Issues

• Standards

• Operating limits

• Case Study

Power Electronics Opportunities

• Transformers

• SSPC/SSCB

• Advanced Power Switches

Case Studies

• AC v. DC


Course ObjectiveCourse Objective

This seminar focuses on the environment power electronics needs

to develop within to provide the “smart” delivery of electric power

from the sub-transmission system to the end user’s meter.

Topics are introduced from an electronics processing / power

electronics v. power systems perspective.

Excerpt from university course taught to power utility engineers.


Masters of EngineeringMasters of Engineering curriculum for practicingcurriculum for practicing

electric utility engineerselectric utility engineers

Offered at the University at Buffalo

Synchronous live broadcast on a trimester schedule


UB UB MEngMEng* Degree Courses* Degree 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* Degree Courses * Degree 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* Degree Courses * Degree 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;



““SMART GRIDSMART GRID”” - Topical Discussion - Topical Discussion

TOPICAL DISCUSSION WAS OMMITTED FROM BOOKLET


http://www.aertc.org/conference09/index.html

The Advanced Energy 2010 conference includesprograms each morning, general sessionsfeaturing one or more keynote speakers, and aposter session. The educational program includesmultiple sessions involving topic experts andthought leaders on the following program tracks:

!Energy Policy, Energy Sector Finance!Battery/Energy Storage/Load Management!Intelligent Transmission, Distribution & Smart Grid!Solar, BioFuels, Wind, Geothermal, Tidal, Hydrogen

Economy!Low Carbon Society, Climate Change & Sustainable

Building!Intelligent Transportation!Energy Efficient Data Centers!Energy Efficient Lighting!Advanced Lighting

Research

Advanced Energy 2010 conferenceAdvanced Energy 2010 conference

"JimSmith" <[email protected]>,

2010


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.

What is the primary “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


A breakdown of what to follow in theA breakdown of what to follow in the

NIST Standards ActivitiesNIST Standards Activities


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 and will be accelerated as a

result of DOE Smart Grid Investment Grants etc.

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

Under the Energy Independence and Security Act of 2007 (EISA), NIST

is assigned the

“primary responsibility to coordinate development of a framework that

includes protocols and model standards for information management to

achieve interoperability of Smart Grid devices and systems…”

There is an urgent need to establish protocols and standards for the

Smart Grid.


• It describes a high-level conceptual reference model for the Smart Grid,

• identifies 75 existing standards that are applicable (or likely to beapplicable) to the ongoing development of the Smart Grid,

• specifies 15 high-priority gaps and harmonization issues (in addition tocyber security) for which new or revised standards and requirements areneeded,

• documents action plans with aggressive timelines by which designatedstandards-setting organizations (SSOs) will address these gaps,

• and describes the strategy to establish requirements and standards to helpensure Smart Grid cyber security

Why NIST Framework (Why NIST Framework (concon’’dd))Recognizing the urgency, NIST developed a

• three-phase plan to accelerate the identification of an initial set ofstandards and

• to establish a robust framework for the sustaining development of themany additional standards that will be needed and

• for setting up a conformity testing and certification infrastructure.

This document: NIST Framework and Roadmap for Smart GridInteroperability Standards, Release 1.0, is the output of the first phaseof the NIST plan.


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


1.4 Content Overview1.4 Content Overview (Areas worth reading) (Areas worth reading)

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?1.3.2 Applications and Requirements1.3.2 Applications and Requirements


[23] Federal Energy Regulatory Commission, Smart Grid Policy, 128 FERC ¶ 61,060 [Docket No. PL09-4-000] July 16, 2009.

1.3.2 Applications and Requirements1.3.2 Applications and Requirements

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,

• i.e. aspects that are especially critical to ongoing and near- term

deployments of Smart Grid technologies and services, including priority

applications were recommended by FERC in its policy statement:23

These “Areas” are: … [by color of importance to power electronics

opportunities]

Peripheral interest with traditional support from existing products

Direct interest as technology can advance in integrated functionality

Primary interest by advanced power electronic systems


1.3.21.3.2 Apps & Apps & ReqReq’’d d Priority AreasPriority Areas

Peripheral interest with traditional support from existing products

Wide-area situational awareness:

Demand response and consumer energy efficiency:

Cyber security:

Network communications:


1.3.21.3.2 Apps & Apps & ReqReq’’d d Priority AreasPriority Areas ( (concon’’dd))

Direct interest as technology can advance in integrated functionality

Advanced metering infrastructure (AMI):

• Currently, utilities are focusing on developing AMI to implement residential

demand response and to serve as the chief mechanism for implementing

dynamic pricing.

• It consists of the communications hardware and software, and associated

system and data management software that creates a two-way network

between advanced meters and utility business systems, enabling

collection and distribution of information to customers and other parties,

such as the competitive retail supplier or the utility itself.

• AMI provides customers real-time (or near real-time) pricing of electricity,

and it can help utilities achieve necessary load reductions.



Primary interest by advanced power electronic systems

Energy storage:

• Means of storing energy, directly or indirectly.

• The significant bulk energy storage technology available today is pumped

hydroelectric storage. New storage capabilities, especially for distributed

storage, would benefit the entire grid, from generation to end use.

Electric transportation:

• Refers, primarily, to enabling large-scale integration of plug-in electric

vehicles (PEVs).

• Electric transportation could significantly reduce U.S. dependence on

foreign oil, increase use of renewable sources of energy, and dramatically

reduce the nationﾕs carbon footprint.



Distribution grid management:

• Focuses on maximizing performance of feeders, transformers, and other

components of networked distribution systems and integrating with

transmission systems and customer operations.

• As Smart Grid capabilities, such as AMI and demand response, are

developed, and as large numbers of distributed energy resources and

plug-in electric vehicles (PEVs) are deployed, the automation of

distribution systems becomes increasingly more important to the efficient

and reliable operation of the overall power system.

• The anticipated benefits of distribution grid management include increased

reliability, reductions in peak loads, and improved capabilities for

managing distributed sources of renewable energy.


NISTNIST Report provides a comprehensiveReport provides a comprehensive

SUMMARY of RELEVANT STANDARDSSUMMARY of RELEVANT STANDARDS

for us to followfor us to follow


Cited Standards of interestCited Standards of interest (See RED later)(See RED later)

4 DNP3 - This standard is used for substation and feeder deviceautomation 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 Standards Topics (Other NIST Standards Topics (concon’’dd))5.15 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.


END - NIST ReviewEND - NIST Review

Onto IEEE Standards


StandardsStandards of Critical Importanceof Critical Importance


SAE J2293, IEEE P2030 & IEEE 1547SAE J2293, IEEE P2030 & IEEE 1547

IEEE P2030 Smart Grid Interoperability Standards Development Meeting,Jan 26-29, 2010,Detroit Edison, Detroit, MI

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

IEEE P2030 Smart Grid Interoperability Standards Development Meeting

January 26-29, 2010, Hosted by Detroit Edison, Detroit, MI


1547- 2003 Standard for Interconnecting Distributed Resources

with Electric Power Systems

1547.1 - 2005 Conformance Test Procedures for

Equipment Interconnecting DR with EPS

1547.2 - 2008 Application Guide for IEEE 1547

Standard for Interconnection of DR with EPS

1547.3 - 2007 Guide for Monitoring, Information

Exchange and Control of DR

Current 1547 ProjectsP1547.4 Guide for Design, Operation, and Integration

of DR Island Systems with EPS

P1547.6 Recommended Practice for Interconnecting

DR With EPS Distribution Secondary Networks

P1547.5 Guidelines for Interconnection of Electric

Power Sources Greater Than 10 MVA to the Power

Transmission Grid Urban distribution

networks

Microgrids

htt

p:/

/gro

up

er.

iee

e.o

rg/g

rou

ps/s

cc2

1/in

de

x.h

tml

P1547.7 Draft Guide to Conducting Distribution

Impact Studies for Distributed Resource

Interconnection

Identified

in Report

to NIST

!"

IEEE 1547 Interconnection StandardsIEEE 1547 Interconnection Standards


Distributed

Energy

Technologies

Interconnection

TechnologiesElectric Power

Systems

Fuel Cell PV

MicroturbineWind

Generator

Inverter

Switchgear,

Relays, &

Controls

Functions

• Power Conversion

• Power Conditioning

• Power Quality

• Protection

• DER and Load

Control

• Ancillary Services

• Communications

• Metering

Microgrids

Energy

Storage

Loads

Local

LoadsLoad Simulators

Utility

System

PHEV;

V2G

!#

Distributed Energy Resources InterconnectionDistributed Energy Resources Interconnection



IEEE P2030 Smart Grid Interoperability Standards Development Meeting

January 26-29, 2010, Hosted by Detroit Edison, Detroit, MI

P2030 Title: “Guide for Smart Grid Interoperability of Energy Technology and

Information Technology Operation with the Electric Power System (EPS) and

End-Use Applications and Loads”

v. Interconnection

IEEE Standard DevelopmentIEEE Standard Development MeetingMeeting

Scope:

This guide provides a knowledge base addressing

• terminology, characteristics, functional performance and evaluation

criteria, and

• the application of engineering principles for smart grid interoperability of

the electric power system with end-use applications and loads.

The guide discusses alternate approaches to good practices for the

smart grid.



3 TASK GROUPS for P20303 TASK GROUPS for P2030

9. Power Systems Intraoperability

• 9.1 Energy Sources

• 9.2 Transmission

• 9.3 Substation

• 9.4 Distribution

• 9.5 Load Side

• 9.6 Cyber Security

10. Information SystemsIntraoperability

• 10.1 Introduction, Purpose, andScope

• 10.2 Power Engineering

• 10.3 Architecture

• 10.4 Modeling

• 10.5 Security

• 10.6 Communications

11. Communications SystemsIntraoperability

• 11.1 Purpose and Scope

• 11.2 Models of the Grid

• 11.3 CategorizedCommunications Use Cases

• 11.4 Architectures

• 11.5 Monitoring and ControlIssues

• 11.6 Communication aspects of:Generation, Transmission,Distribution, Microgrids, LoadManagement


P2030 DraftP2030 Draft

Check the standards DRAFT on

the web.

https://mentor.ieee.org/2030/bp/StartPage

APEC’10, Palm Springs, CA © 2010, D. C. [email protected]!$

1547&P2030 Considerations in NIST 1547&P2030 Considerations in NIST RptsRpts

Energy Storage Systems, e.g., IEEE 1547/2030 extensions for storage

system specific requirements

Distribution Grid Management Initiatives, e.g., extensions of 1547 series

and/or P2030 series, including communications

Voltage Regulation, Grid Support, etc., e.g., develop specifications in

P1547 and/or P2030-series

Management of DER, e.g. Planned island systems

Static and Mobile Electric Storage, including both small and large electric

storage facilities.

Electric Transportation and Electric Vehicles.


P1809P1809 Electric TransportationElectric Transportation

New Standard committee

First meeting - 18 February 2010

PRESENTATIONS Continuation:

• DOE – Keith Hardy, Grid Interaction Tech Team Lead – 15 minutes

• NREL – Tony Markel, Senior Engineer – 15 minutes

• NIST – Eric Simmon, PAP11 Lead – 15 minute

• SAE – Gery Kissel, Chair SAE J1772 – 10 minutes

• SAE – Rich Scholer, Chair SAE J2847/J2836 -10 minutes

• SAE – Robert Gaylen, Chair SAE Battery Committee – 10 minutes

• APTA – Martin Schroeder, Chief Engineer – 15 minutes

• EEI – Steven Rosenstock, Manager, Energy Solutions - 15 minutes

• NRECA – Andrew Cotter, Senior CRN Program Management Advisor - 10

minutes

• IEEE SA – Mike Kipness, Program Manager, Technical Program Development –

10 minutea


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


WhatWhat is the Smart Grid?is the Smart Grid?

How do we survive within the Legacy System?


What isWhat is the Smart Grid?the Smart 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

(2): Flow is regulated by ISOs (Independent System Operators)

(2): General contrast between NE v. W -- Mesh v. Point-to-Point

(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)

TRANSFORMERS AND PROTECTION ARE OF MAIN INTEREST

Distribution transformer is on the pole;

Substation transformer is on the ground in the Distribution Substation/Switch Yard


“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 Nutshell (Structure of Interest in a Nutshell (concon’’dd))

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


A Test Bed for Smart PowerA Test Bed for Smart Power

DevelopmentDevelopment

The Intelligent Substation

Proposed test bed at the University at Buffalo


From: N.Mohan, “First Course on Power Electronics, 2005

Power Electronic ApplicationsPower Electronic Applications

Distributed generation (DG)

• Renewable resources (wind and photovoltaic)

• Fuel cells and micro-turbines

• Storage: batteries, super-conducting magnetic energy storage, flywheels

Power electronics loads: Adjustable speed drives

Power quality solutions

• Dual feeders

• Uninterruptible power supplies

• Dynamic voltage restorers

Transmission and Distribution (T&D)

• High voltage dc (HVDC) and medium voltage dc

• Flexible AC Transmission Systems (FACTS): Shunt and Series

compensation, and the unified power flow controller


Site DevelopmentSite Development Smart Distribution Smart Distribution SystSyst


Development Platform-Development Platform-The Intelligent Substation

•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


Utility ApplicationsUtility Applications

Distributed Generation (DG) Applications

AC

DC

DC

AC

Wound rotor

Induction Generator

Generator-side

Converter

Grid-side

Converter

Wind

Turbine

Isolated

DC-DC

Converter

PWM

Converter

Max. Power-

point Tracker

Utility

1f

Wind Power Generation with

Doubly Fed Induction Motors

Photo-voltaics Interface



Utility ApplicationsUtility Applications ( (concon’’dd))

Power Quality Solutions for

• voltage distortion

• unbalances

• voltage sags and swells

• power outages

Dual Feeders

Power Electronic

InterfaceLoad

Dynamic Voltage Restorers (DVR)

Uninterruptible Power

Supplies

Rectifier Inverter FilterCritical

Load

Energy

Storage


Feeder #1

Feeder #2

Solid State

Switches

LOAD


Utility ApplicationsUtility Applications ( (concon’’dd))

Transmission and Distribution: DC Transmission

• most flexible solution for connection of two ac systems

AC1 AC2

HVDC

AC1 AC2

MVDC



Background - T&D Systems and FACTSBackground - T&D Systems and FACTS

Stability

Power flow controlDirectional routing

Quality control

Power conversion (MVDC)

What control is needed in the power syst?


Power and Control SensitivityPower and Control Sensitivity

Starting with Transmission Model…


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

SB = PB + jQB = VB • I * , (receiving end)

!

r I = Eg"# $VB"0( ) jX B( )r I = Ege

j # $90o( )$VB e

j 0$90o( )%

& '

(

) * X B

r I + = Ege

$ j # $90o( )$VB e

$ j 0$90o( )%

& '

(

) * X B


Computing power Computing power transfered transfered (flow)(flow)

!

Remember : SB = PB + jQB = VB • I *

SB = VB Ege+ j 0"# +90

o( )"VB

2e+ j 0"0 +90

o( )$

% &

'

( ) X B

= jVB Eg cos("# )+ j sin("# ){ } " jVB2[ ] X B

!

cos("# ) = cos(+# ); j cos(# ) = sin(# ); j sin("# ) = " j sin(+# ) = cos(# )

!

Therefore :

SB = VB Eg sin(" )+ jVB Eg cos(" )# jVB2[ ] X B

P jQ


Real and Real and Quadrature Quadrature PowerPower

!

Real Power (P) :

P =VB Eg

X B

sin(" )#

$ % %

&

' ( ( P

ow

er[W

]

![rad]

!

SB = PB + jQB

Quad P

ow

er[V

AR

s]

![rad]

!

Quadrature Power (QB ) :

jQB =

j VB Eg cos(" )#VB( )$ % &

' ( )

X B

= jVB Eg

X B

cos(" )#VB

2

X B

$

% & &

'

( ) )


• Influence the magnitude of the voltage from the source.

• Influence the line reactance.

• Influence the magnitude of the load bus voltage.

• Influence the angle, !2, of the load. (! = / Eg - / VB )

How can you change power flow?How can you change power flow?

Eg / ! VB / 0

jXB

+ I -

!

Real Power (P) :

P =VB Eg

X B

sin(" )#

$ % %

&

' ( (


Introduction to FACTSIntroduction to FACTS ControllersControllers

Conceptual overview of controllers

and how they can be used.


Helping in power managementHelping in power management

• Control of power flow as ordered, ensure optimum flow, redirect flow

during emergencies, increase utilization of lowest cost generation, etc.

• Increase dynamic line loading to thermal limits adjusted for seasonal

and environmental conditions, and according to loading history.

• Increase transient stability, limit short-circuit currents and overloads,

manage cascading blackouts, and dampen electromechanical and sub-

synchronous resonances.

• Provide secure tie line connections to neighboring utilities and regions

thereby decreasing overall generation reserve requirements on both

sides.

• Reduce reactive power flows and loop flows, allowing the lines to carry

more active power.

• Provide greater flexibility in siting new generation, upgrading lines, etc.

Controllers help distribution and transmission owners to:


General placementGeneral placement

Series controller

Inter-tie controller

Shunt controller

DCw/ storage

DC

dc link

Unified series-shunt controller

(w, w/o storage)


Alphabet soup for the controllers -Alphabet soup for the controllers - these are thethese are the

definitions from the IEEE working groupdefinitions from the IEEE working group

Part I - SHUNT CONTROLLERS


Shunt controller

- voltage source

Shunt controller

- current source

Static Synchronous CompensatorStatic Synchronous Compensator

Static synchronous generator

operated as a shunt-connected static

VAR compensator whose capacitive

or inductive output current is

controlled.

STATCOM is one of the key FACTS

Controllers and based on voltage-

source converters (VSCs) or current-

source converters. The VSCs are

more cost effective and preferred.

The capacitor voltage is

automatically adjusted as required to

serve as a voltage source for the

converter.

STATCOMs can be designed to also

act as an active filter to absorb

system harmonics.

(STATCOM)(STATCOM)

Bi-D

irect

iona

l con

v.

<v>=0


Static Synchronous Generator (SSG)Static Synchronous Generator (SSG)

A self-commutated switching power

converter supplied from an

appropriate electric energy source

and operated to produce a set of

adjustable multiphase output

voltages, which may be coupled to

an ac power system for the purpose

of exchanging independently

controllable real and reactive power.

•SSG is a combination of STATCOM

and energy source

•Supplies or absorbs power

Shunt controller

- voltage source

interface converter

energystorage

•May use

•battery (Battery Energy Storage System (SSG-BESS)),

•flywheel,

•superconducting magnet (Magnetic Energy Storage (SSG-SMES)),

•large dc storage capacitor, another rectifier/inverter, etc.


Static VAR Compensator (SVC)Static VAR Compensator (SVC)

A shunt-connected static var generator or absorber whose output is

adjusted to exchange capacitive or inductive current so as to maintain

or control specific parameters of the electrical power system

A.K.A.: thyristor-controlled or thyristor-switched reactor for absorbing

reactive power, and/or thyristor-switched capacitor for supplying the

reactive power, or combination

SVC is based on simple SCRs and considered by some as a lower cost

alternative to STATCOM, although this may not be the case if the

comparison is made based on the required performance and not just

the MVA size.


SVC-Thyristor Controlled Reactor (TCR)SVC-Thyristor Controlled Reactor (TCR)

A shunt-connected, thyristor-

controlled inductor whose

effective reactance is varied in a

continuous manner by partial-

conduction control of the thyristor

•TCR is a subset of SVC in which

conduction time and hence,

current in a shunt reactor,

controlled by a thyristor-based ac

switch with firing angle controlSVC-TCR, Thyristor

Controlled Reactor


SVC-Thyristor Switched Reactor (TSR)SVC-Thyristor Switched Reactor (TSR)


switched inductor whose effective

reactance is stepwise varied by

full- or zero-conduction operation

of the thyristor.

•TSR is made up of several shunt

connected inductors switched in

and out by thyristors

•Controls achieve step changes

in the reactive power consumed

from the system.

•Use of thyristor switches without

firing angle control results in

lower cost and losses, but without

a continuous control.

SVC-TSR, Thyristor

Switched Reactor


SVC-Thyristor Switched Cap (TSC)SVC-Thyristor Switched Cap (TSC)


switched capacitor set whose

effective reactance is stepwise

varied by full- or zero-conduction

operation of the thyristor.

•Thyristors switch shunt

capacitors units in and out

(without firing angle control) to

achieve step changes in the

reactive power supplied to the

system.

•Unlike shunt reactors, shunt

capacitors cannot be switched

continuously with variable firing

angle control.

SVC-TSC, Thyristor

Switched Capacitor


Static VAR Gen. or AbsorberStatic VAR Gen. or Absorber

A static electrical device, equipment, or system capable of drawing

controlled capacitive and/or inductive current from an electrical power

system, thereby generating or absorbing reactive power. Generally

considered to consist of shunt-connected, thyristor-controlled reactor(s)

and/or thyristor-switched capacitors.

Both the SVC and the STATCOM are static VAR generators equipped

with appropriate control loops to vary the VAR output so as to meet

specific compensation objectives.

Static VAR System (SVS)Static VAR System (SVS)A combination of different static and mechanically-switched VAR

compensators whose outputs are coordinated.


Thyristor Thyristor CtrlCtrl’’d d Braking Resistor (TCBR)Braking Resistor (TCBR)

A shunt-connected thyristor-

switched resistor to aid

stabilization of a power system or

to minimize power acceleration of

a generating unit during a

disturbance.

•TCBR involves cycle-by-cycle

switching of a resistor with

thyristor-based firing angle

control

•Can be utilized to selectively

damp low-frequency oscillations.

SVC-TCBR, Thyristor

Switched Braking Resistor


Alphabet soup for the controllers - these are theAlphabet soup for the controllers - these are the

definition from the IEEE working groupdefinition from the IEEE working group

Part II - Series Controllers


Static Sync. Series Compensator (SSSC)Static Sync. Series Compensator (SSSC)

A static synchronous generator operated without an external electric

energy source as a series compensator whose output voltage is in

quadrature with the line current for increasing or decreasing overall

reactive voltage drop across the line

The SSSC may include transiently rated energy storage or absorbing

devices to enhance the dynamic response by temporary addition of real

power to increase or decrease the overall real (resistive) voltage drop

across the line.

• SSSC is one the most important FACTS Controllers. It is like a

STATCOM, except that the output ac voltage is in series with the line.

• It can be based on a VSC or current-sourced converter.

• Battery-storage or superconducting magnetic storage can be added to

inject a voltage vector of variable angle in series with the line.


Interline Power Flow Controller (IPFC)Interline Power Flow Controller (IPFC)

New/possible definition: Combination

of two or more SSSCs coupled via a

common dc link to facilitate bi-

directional flow of real power

between the SSSCs, and are

controlled to provide independent

reactive compensation in each line.

The IPFC structure may also include

a STATCOM, coupled to the IPFC's

common dc link, to provide shunt

reactive compensation and supply or

absorb the overall real power deficit

of the combined SSSCs.


Alphabet codeAlphabet code

R(Reactor)

S(Switched)

C(Capacitor)

S(Series)

C(Controlled)

T(Thyristor)


TCSC, Thyristor

Controlled Series

Capacitor

Thyristor Thyristor CtrlCtrl’’d d Series Capacitor (TCSC)Series Capacitor (TCSC)

Capacitive reactance compensator

consisting of a series capacitor bank

shunted by a thyristor-controlled

reactor (TCR) to provide smoothly

variable series capacitive reactance.

The TCSC uses SCRs

When the TCR firing angle is 180º,

the reactor is non-conducting and the

series capacitor has normal

impedance. As the firing angle is

advanced from 180º, the capacitive

impedance increases

When the TCR firing angle is 90, the

reactor becomes fully conducting,

and the total impedance becomes

inductive

MOST COMMON


TCSC, Thyristor

Controlled Series

Capacitor

Thyristor-Sw. Series Capacitor (TSSC)Thyristor-Sw. Series Capacitor (TSSC)

Capacitive reactance

compensator consisting of a

series capacitor bank shunted by

a thyristor-switched reactor to

provide stepwise control of series

capacitive reactance.

Switches inductors at firing angle

90º or 180º without firing angle

control to reduce cost and losses

of the Controller

Could combine thyristor control,

and thyristor switching.


Thyristor-CtrThyristor-Ctr’’d d Series Reactor (TCSR)Series Reactor (TCSR)

An inductive reactance


series reactor shunted by a

thyristor controlled reactor to

provide a smoothly variable

series inductive reactance.

When the firing angle of the

thyristor controlled reactor is 180º

degrees, it stops conducting, and

the uncontrolled reactor acts as a

fault current limiter

As the angle decreases, the net

inductance decreases until firing

angle of 90º, when the net

inductance is the parallel

combination of the two reactors.


Thyristor-Sw. Series Reactor (TSSR)Thyristor-Sw. Series Reactor (TSSR)

:An inductive reactance


series reactor shunted by a

thyristor switched reactor to

provide stepwise control of series

inductive reactance.

This is a complement of TCSR,

but with thyristor switches fully on

or off (without firing angle control)

to achieve a combination of

stepped series inductances


Alphabet soup for the controllers - these are theAlphabet soup for the controllers - these are the

definition from the IEEE working groupdefinition from the IEEE working group

Part III - Combined Shunt and Series

Controllers


Unified Power Flow Controller (UPFC)Unified Power Flow Controller (UPFC)

A combination STATCOM and SSSC

coupled via a common dc link (for

bidirectional flow of real power

between the two) and are controlled

to provide concurrent real and

reactive series line compensation

without an external electric energy

source.

The UPFC is able to control the

transmission line voltage,

impedance, and angle or,

alternatively, real and reactive power

flow in the line.

The UPFC may also provide

independently controllable shunt

reactive compensation.

Additional dc storage, can provide

further effectiveness


(TCPST)(TCPST)A phase-shifting transformer

adjusted by thyristor switches to

provide a rapidly variable phase

angle.

Phase shifting is obtained by

adding a perpendicular voltage

vector in series with a phase.

The vector is derived from the

other two phases via shunt

connected transformers.

Thyrst-CtrlThyrst-Ctrl’’d d Phase Shifting Phase Shifting TfrmrTfrmr


Interphase Interphase Power Controller (IPC)Power Controller (IPC)

A series-connected controller in

each phase of inductive and

capacitive branches subjected to

separately phase-shifted

voltages.

The active and reactive power

can be set independently by

adjusting the phase shifts and/or

the branch impedances, using

mechanical or electronic

switches.


Thyristor-CtlThyristor-Ctl’’d d Voltage Limiter (TCVL)Voltage Limiter (TCVL)

A thyristor-switched metal-oxide

varistor (MOV) used to limit the

voltage across its terminals

during transient conditions.


Thyristor-CtrlThyristor-Ctrl’’d d Volt. Regulator (TCVR)Volt. Regulator (TCVR)

A thyristor-controlled transformer

which can provide variable in-

phase voltage with continuous

control.

Uses a transformer with thyristor-

controlled tap changing or

Thyristor-controlled ac-ac

converter for injection of variable

ac voltage of same phase in

series with the line

Such a relatively low cost

controller can effectively control

the flow of reactive power

between two ac systems.


Technical ReviewTechnical Review & Discussion -& Discussion -

Concept DevelopmentConcept Development

Brief Discussion of:

• Symmetrical Components

• Harmonics

• Power Control

• Power Flow

[FURTHER SLIDES ON TOPIC OMMITTED]


Symmetrical ComponentsSymmetrical Components

- CONCEPT ONLY-- CONCEPT ONLY-

An easy method to understand unbalanced

system operation is through

Symmetrical Components


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.

The key idea of Symmetrical Component analysis is to decompose the

system into three sequence networks. The networks are then coupled

only at the point of the unbalance (e.g., the fault)

The three sequence networks are known as the: Positive Sequence,

Negative Sequence and Zero Sequence

To Analyze Unsymmetrical Systems:To Analyze Unsymmetrical Systems:

1. Use direct network calculations or circuit simulation, or

2. Use “Symmetrical Coordinates” as proposed by Charles L. Fortescue

[AIEE Transactions, V37 Part 2, 1918], now know as “Symmetrical

Components”


Concept of Symmetrical ComponentsConcept of Symmetrical Components

We already understand how to map a general vector into two orthogonal

vectors that are on real and imaginary axes.

Now 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

PhasorPhasors with 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


Background UnderstandingBackground Understanding

- CONCEPT ONLY-- CONCEPT ONLY-

Brief Discussions:

Harmonics and Fourier Series, Harmonic Power and

THD, Per Unit System

Not in notes


Harmonics (i.e. Fourier Series)Harmonics (i.e. Fourier Series)

Fundamentally important for power quality, harmonic

control and high frequency design


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 an easier view for conceptualization….

!

f t( ) = a0 + an cos nwt( ) + bn sin nwt( )[ ]n=1

"

#

Time varying sinusoids displaced by 90˚

Magnitudes for each sinusoid

Note: for “even symmetry” about the y axis, bn = 0 ;

for “odd symmetry” about the origin, an=0


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


Each cosine term, cn cos(n!t + "n), is called a Fourier Component or a

Harmonic of the function f(t) with “n” harmonics.• cn is the “amplitude” component;

• "n is the component phase;

• c0 = a0 is the dc component, the average value of f(t), c0 = <f(t)>.

Polar Form (best for conceptualization)Polar Form (best for conceptualization)

We can also write

The term c1 cos(!t + "1) is the “fundamental” of f(t), while 1/T is the

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 Cycle Duty Cycle variationvariation

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 to SwitchingDistortion is Fundamental to Switching

There 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:


Per Unit SystemPer Unit System of Calculationsof Calculations


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.

Convert actual values to per unit

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

! ! !! != = = =

© 2003 Tom Overbye, University of Illinois at Urbana-Champaign,All Rights Reserved


Electric Power DistributionElectric Power Distribution

and Utilization Standardsand Utilization 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 Radial SystemPlacement in Simple Radial System

Transformer

• 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 Bus SystemPlacement in Simple Ring Bus System

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))


Standards - Voltage RangesStandards - Voltage Ranges


ANSI C84.1 standardANSI C84.1 standardThe American National Standard Institute (ANSI) has developed the

Standard C84.1 which is designed to establish nominal voltage ratingsand operating tolerances for 60-hertz electric power systems between100V and 230kV. The purposes of the ANSI C84.1 standard are to :

Promote a better understanding of the voltages associated with powersystems and utilization equipment to achieve overall practical andeconomical design and operation.

Establish uniform nomenclature in the field of voltages

Promote standardization of nominal system voltages and ranges ofvoltage variations for operating systems

Promote standardization of equipment voltage ratings and tolerances

Promote coordination of relationships between system and equipmentvoltage ratings and tolerances

Provide a guide for future development and design of equipment toachieve the best possible conformance with the needs of the users

Provide a guide, with respect to choice of voltages, for new power systemundertakings and for changes in old ones.


550, 575600

440480

460Y/265480Y/277

230, 250240

240/120

216Y/125208Y/120

110, 115, 125120

110/220, 115/230, 125/250120/240

Associated nonstandard System

Voltages

Standard Nominal System Voltages

Standard Voltages - Low VoltagesStandard Voltages - Low Voltages


66 00069 000

44 00046 000

33 00034 500

34 500Y/19 920

24 940Y/14 400

23 000

22 860Y/13 200

20 780Y/12 000

13 800

14 40013 800Y/7970

13 200

13 200Y/7620

12 470Y/7200

12 000Y/6930

11 000, 11 5008320Y/4800

6600, 72006900

46004800

40004160

4160Y/2400

2200, 23002400

Associated nonstandard System VoltagesStandard Nominal System Voltages

Standard Voltages - Medium VoltagesStandard Voltages - Medium Voltages


220 000230 000

154 000161 000

132 000138 000

110 000, 120 000115 000


Voltages


765 000

500 000

345 000


Voltages


Standard Voltages - High VoltagesStandard Voltages - High Voltages


Ranges A & BRanges A & B

Range A :

Service Voltage : Electric supply systems shall be so designedand operated that most service voltages will be within thelimits specified for Range A. The occurrence of servicevoltages outside of these limits should be infrequent.

Utilization Voltage : Electrical systems shall be designed andoperated within the voltage range defined as Range A; whichmost utilization voltages being specified within this range.

Utilization equipment shall be designed and rated to givefully satisfactory performance throughout range A.


Range ARange A & B& B

Range B :

Service and Utilization Voltage: Range B includes voltagesabove and below Range A limits that necessarily result frompractical design and operating conditions on supply or usersystems, or both. Although such conditions are a part ofpractical operations, they shall be limited in extent, frequency,and duration. When they occur, corrective measures shall beundertaken within a reasonable time to improve voltages tomeet Range A requirements.

Insofar as practicable, utilization equipment shall be designed togive acceptable performance in the extremes of the range ofutilization voltages, although not necessarily as goodperformance as in Range A.


Range of RangesRange of Ranges

copyrighted by IEEE


Flicker (IEEE Std 141-1993)Flicker (IEEE Std 141-1993)

copyrighted by IEEE


System Protection -System Protection -

SSSSTransformer Transformer and SSCB Requirementsand SSCB Requirements

The SST and SSCB will need to open under full fault

current and perform in legacy systems as traditional CB

operate. A set of metrics are given as guide to Smart

Breaker development


Fundamental considerationsFundamental considerations

Reliability- Denotes certainty of correct operation together with assurance

against incorrect operation from all extraneous causes.

Speed – to obtain the minimum fault clearing time and damage to

equipment.

Selectivity – Complete selectivity being obtained when a minimum

amount of equipment is removed from service for isolation of a fault or

other abnormality.

Economics – Maximum protection at minimum cost.

IEEE Std 242-2001, Recommended Practice for Protection and Coordination of Industrialand Commercial Power Systems (IEEE Buff Book)


Analysis of System and ProtectionAnalysis of System and Protection

Even with the best design possible, materials deteriorate and the

likelihood of faults increases with age.

Operating records show that the majority of electric circuit faults originate

as phase-to-ground faults.

In grounded systems, phase-to-ground faults produce currents of

sufficient magnitude for detection by ground-fault responsive

overcurrent relays.

If the system neutral is grounded through a proper impedance, the value

of the ground-fault current can be restricted to a level that would avoid

extensive damage at the point of the fault, yet adequate for ground-

fault relaying.

In ungrounded systems, phase-to-ground faults produce relatively

insignificant values of fault current. In small installations, with isolated

neutral, the ground-fault current for a single line-to-ground fault may be

well under one ampere. Overcurrent relays are not generally used to

detect and isolate this low current fault.


Distortion of Phase V & I During FaultsDistortion of Phase V & I During Faults

copyrighted by IEEE


Normal and 3-ph faultNormal and 3-ph fault

copyrighted by IEEE


SeveralSeveral types of faultstypes of faults

copyrighted by IEEE


IEEE_Std_C37.2._2008

Some types of Circuit BreakersSome types of Circuit Breakers

Overcurrent relays;

Overcurrent relays with voltage

restraint or voltage control;

Directional relays;

Differential relays;

Current balance relays;

Ground-fault relays;

Synch-check and synchronizing

relays;

Pilot-wire relays;

Voltage relays;

Distance relays;

Phase-sequence or reverse-

phase relays;

Volts/Hz over-excitation relays;

Frequency relays;

Temperature-sensitive relays;

Pressure-sensitive relays;

Replica-type temperature relays;

Auxiliary relays;

Direct-acting trip devices for low-

voltage power circuit breakers;

Power fuses


Time-CurrentTime-Current (typical time(typical time-1-1 OC OC Relay)Relay)

copyrighted by IEEE


Typical Electro-MechanicalTypical Electro-Mechanical

Solid State is much

faster. However, the

system must be

compatible with faster

response times.

copyrighted by IEEE


Typical Typical t-I t-I plot for SS Trip Deviceplot for SS Trip Device

copyrighted by IEEE


Impulse Voltage Withstand RequirementsImpulse Voltage Withstand Requirements

New standards and system requirements may be

needed for power electronics equipment to

economically withstand transient over-voltages

Surge voltages occur from, e.g. lightning and the

reflections from the resultant traveling waves

Cabling becomes more of a challenge


When wavelengths are short compared to the physical length of

circuitry, then it may be necessary to use “distributed-constant”

representation

Surge Voltage PropagationSurge Voltage Propagation

copyrighted by IEEE


Inductance L and capacitance C are expressed in

per unit length.

Stored energy in inductance is # LI 2

Stored energy in capacitance is # CE 2

Equating the two, we get

The wave propagation velocity is expressed as 1/$LC

It approximates speed of light [1000 ft/µs]

C

L

I

EZ ==0

Typical values of Z0: 200-400# for overhead Lines

20-50 # for insulated cables

Surge voltage propagation (Surge voltage propagation (concon’’dd))


10" 20" 40" 70"

E

1.33E 1.78E 2.27E 4.54E

Et

Voltage at the point of refraction = (E)(2Z2)/(Z2 + Z1)

Amplification PhenomenaAmplification Phenomena

A traveling surge-voltage, encountering in succession junctions with

higher surge impedance, may have its voltage magnitude elevated to a

value in excess of twice the magnitude of the initial voltage.


Standardized factory tests:

• 1 minute high potential [ hi-pot] test at power frequency

• 1.2/50 full-wave voltage impulse test

• For low voltage [<1000 V] equipment, additional wave shapes are

prescribed in IEEE std. C62.41.2-2002

Insulation Voltage WithstandInsulation Voltage Withstand

Insulation tests and ratings:

Standards have been developed that recognize the need for electrical

equipment to withstand a limited amount of temporary excess voltage

stresses above and beyond the normal operating voltages.


IEEE C62.41.2-2002IEEE C62.41.2-2002

copyrighted by IEEE


100kHz Ring Wave (V & I)100kHz Ring Wave (V & I)

IEEE C62.41.2-2002IEEE C62.41.2-2002

copyrighted by IEEE


BIL

1.2!s

50!s

For tables: 6-1,2,3,& 4 in IEEE C62.41.2

Full-wave voltage impulse test waveFull-wave voltage impulse test waveBIL: Basic Impulse Insulation Level

copyrighted by IEEE


Combination Wave for Short Combination Wave for Short Ckt Ckt II

copyrighted by IEEE


Transformer Insulation Overvoltage TestsTransformer Insulation Overvoltage Tests

copyrighted by IEEE


copyrighted by IEEE


copyrighted by IEEE


copyrighted by IEEE


Harmonics in Distribution SystemHarmonics in Distribution System


Harmonics in the systemHarmonics in the system

For system analysis purpose, the non-linear devices (e.g. power

electronics) can be generally treated as current sources of harmonics

The amount of harmonic voltage distortions depends upon Z v. f

characteristics as seen by the harmonic currents.

Higher the short circuit capacity of the system, lower the source

impedance of the system and, hence, lower the voltage distortions due

to harmonic currents.

Capacitor banks used for voltage control or reactive compensation can

be considered in parallel with the system when calculating the

commutating reactance, which would increase di/dt of commutation.

• Capacitance of insulated cables has similar effect.


Normal flow of harmonic currents

Parallel Resonance conditions

L

Cresonance

X

X

MVAinsizebankcapacitor

MVAcircuitShortH ==

Capacitor bank resulting in series resonance

Higher FrequenciesHigher Frequencies Elicit ResonanceElicit Resonance


It is important to be able to analyze a system’s frequency response

characteristics in order to avoid having system resonance problems.

Harmonic currents flow from the non-linear load towards the point of

lowest impedance, usually the utility source.

System response characteristicsSystem response characteristics

Effects of harmonics can be grouped into three general categories

1. Effects on the power system – additional losses, radiated and

conducted noise, signature problems ( submarines)

2. Effects on the loads- motors/generators, transformers, power cables,

capacitors, electronic instrumentations, switchgear & relaying, static

power converters

3. Effects on communications [SCADA systems] – Telephone

Interference Factor [TIF] weighing –


Cable Cable Derating Derating v. Harmonicv. Harmonic

for six-pulse converterfor six-pulse converter

copyrighted by IEEE


VoltageVoltage Distortion Limits (Distortion Limits (!!69kV)69kV)

Industry Standards--IEEE Std. 519- 1992

copyrighted by IEEE


Current DistortionCurrent Distortion Limits (120V - 69kV)Limits (120V - 69kV)

copyrighted by IEEE


Case StudiesCase Studies

Case Studies Presented Interactively

1. One study included herein

2. Remaining study not included


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 VSD at point-of-load1-Ph v. DC for VSD at point-of-load

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


ConclusionsConclusions

Both DC and Single-phase AC transmission are more cost effective than

the 3-phase AC transmission 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.


End - Printed BookletEnd - Printed Booklet

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

[email protected]

www.DCHopkins.Com

Prof. Mohammed Safiuddin, Ph.D.Research Professor

State University of New York at Buffalo

332 Bonner Hall

Buffalo, New York 14260-1900

+01-716-645-3115

Documents

Power Electronics in a Smart-Grid Distribution System (pdf)