EE 303 Introduction 2013

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EE 303 Energy Systems and

Power ElectronicsText Book: Electric Power Principles :Sources, Conversion, Distribution and Use/ J.L. Kirtley

EE 303 notes available at copy works

Online ISU text books:

Electric Power Systems : A Conceptual Introduction/ Alexandra von Meier

Introduction to electrical power systems / Mohamed E. El-Hawary

Renewable and Efficient Electric Power Systems/Gilbert M. Masters


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Course Contents

Covers Generation, Transmission , Distributionand Power Electronics

Single Phase , Three phase and Per unit

Generation Transformers

Transmission and Power flow

Economic Dispatch Distribution

Power Electronics


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Main Elements of a Power Network

Generation

Transmission

Distribution


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Power System Generation & Transmission

Power circuits can be single-phase or 3-phase

N S

Single phase

Generation & transmission is always 3-phase because

Requires 3 wires (if balanced) instead of 6

Power is constant and large motors run smoother

N S

3-phase

X

X X

X


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Transmission


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1100 kV Line


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Voltage Levels

Generation: 1kV-30 kV

EHV Transmission: 500kV-765kV

HV Transmission: 230kV-345kV Subtransmission system: 69kV-169kV

Distribution system: 120V-35kV

About 40% of power system investment is in the distribution system

equipment (40% in generation, 20% in transmission).


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Transformers; how they work

Only works with AC!

V2 can be larger or smaller than V1

2

1

2

1

N

N

V

V


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US Electric Transmission System


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North American Electric Reliability Council (NERC)

E C t l C t


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Energy Control Centers

Energy Control Center (ECC):

SCADA, EMS, operational personnel Heart (eyes & hands, brains) of the power system

Supervisory control & data acquisition (SCADA): Supervisory control: remote control of field devices

Data acquisition: monitoring of field conditions

SCADA components: Master Station: System Nerve Center located in ECC

Remote terminal units: Gathers data at substations; sends to Master

Station

Communications: Links Master Station with Field Devices

Energy management system (EMS) Topology processor & network configurator

State estimator and power flow model development

Automatic generation control (AGC), Optimal power flow (OPF)

Security assessment and alarm processing


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Substation

Remote

terminal

unit

SCADA Master Station

Commu

nicationli

nk

Energy control center with EMS

EMS alarm displayEMS 1-line diagram


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Substations: where transmission lines meet, & wheretransformers & protection equipment are located


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Substations

Substation equipment :

Transformer to change the voltage and current level.

Circuit breaker (CB) to interrupt the load and fault current. The fault currentautomatically triggers the CB.

Disconnect switch to provide visible circuit separation. Permit CBmaintenance. No load operation.

Voltage and current transformers to reduce the current to 5 A, and thevoltage to 120 V, and to insulate the measuring circuit from the high voltage

Surge arresters for protection against lightning and switching overvoltages.They are voltage dependent, non linear resistance.


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Arial View of a Substation


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69 kV substation

Circuit

breakerDisconnect Disconnect

Current CT

Bus bar

Circuit


Current CT

Bus bar

Circuit


Current CT

Bus bar


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500 kV Circuit breaker


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Disconnect Switch

OpenOpen


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Surge Arrester


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Radial Distribution system

Feeder 4Feeder 1

Feeder 2

Feeder3

Three-phase Four-wire

Main Feeder

Neutral

Re-closing

Circuit Breaker

Fuse

Single-phase

Radial Feeder

Single-phase

Radial Feeder

Sub-transmission Line

To Consumer

Service Drop

Distribution

(Step-down)

Transfomer

}


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Cable and transmission line

junction

Line

Fuse cutout

Cables

Surge

arrester


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Consumer Service Drop

Fuse

cutoutSurge

arrester

12.47 kV

Line

Transformer


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Sub-transmission and Distribution line

Distribution line13.8 kV

Transformer

240/120V line

Fuse and disconnector

Telephone line

Distribution Cable13.8 kV


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Doubly Fed Induction

Generators(DFIGs)


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lightning induced

flashover!


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arc across 400kV insulator


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Staged Faults on400kV line

T t t


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Tree-contactTrees were overgrown because right-of-

ways had not been properly maintained.

Lines expand and sag due to heat; more

prone in summer with high temperature &

low winds; more prone with high current.

Each successive line trip requires that thepower it was carrying be transferred to

flow elsewhere, resulting in increased

power on remaining lines.

Bl k t


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BlackoutsSummary of well-known blackouts

Location Date Scale in term of MW orPopulation Collapsetime

US-NE[1] 10-11/9/65 20,000 MW, 30M people 13 mins

New York[2] 7/13/77 6,000 MW, 9M people 1 hour

France[3] 1978 29,000 MW 26 mins

Japan[4] 1987 8,200 MW 20minsUS-West[5] 1/17/94 7,500 MW 1 min

US-West[5] 12/14/94 9,300 MW

US-West[5] 7/2/96 11,700 MW 36 seconds

US-West[5] 7/3/96 1,200 MW > 1 min

US-West[5] 8/10/96 30,500 MW > 6 mins

Brazil[6] 3/11/99 25,000 MW 30 secs

US-NE[7] 8/14/03 62,000 MW, 50M people > 1 hour

London[8] 8/28/03 724 MW, 476K people 8 secs

Denmark & Sweden [9][10] 9/23/03 4.85M people 7mins

Italy[11] 9/28/03 27,700 MW, 57M people 27mins


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POWER ELECTRONICS

&ELECTRIC DRIVES


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Power Electronics deals with the conversion of power

1 , 3 , 60 Hz

or DC

Can be variable voltage and frequency (f)

Performance Criteria Metrics :

Efficiency, Availability, Low Cost, Small Size,

Power quality ..


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Static ( non rotating parts : DC power supply, HVDC , Welding )

Load

Dynamic : ( Contains moving or rotating parts : Pumps,

Conveyor belts, Electric Trains, Motors)


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Range of power conversion : 1kW up to 10GW

Power Semiconductor Devices

Un-Controlled ControlledSemi-Controlled

DiodeThyristor (SCR) or SiliconControlled Rectifier

Triode Alternating Current Switch(TRIAC)

Metal Oxide Silicon Field

Effect Transistor (MOSFET)

Insulated Gate Bipolar Transistor (IGBT)

Gate turn-off thyristor (GTO)

SCR on air-cooled

kits


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Power Electronics Applications

Transmission Systems( HVDC, Flexible AC Transmission Systems(FACTS) )

Smart Grid Applications

(ABB, Siemens, Hitachi ..)

DistributionCustom Power, Smart meters

StorageBattery, Flywheel , Super capacitor,

GenerationSolar, Wind, Fuel Cell, Micro-Turbine, Hydro


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IndustrialPower quality, un-interruptible power supplies, variable speed

drives, rail transportation, electric/hybrid vehicles

Power Electronics Applications cont..

MilitaryAll electric ship, aircraft, virtual reality

Residential/CommercialAppliances, Heat pumps/Airconditioners, Computers


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Power Electronics Converters

1 , 3 AC to DC: RECTIFIER

DC to DC: CHOPPER

DC to 1 , 3 AC: INVERTER

3 AC to 3 AC:

CYCLOCONVERTER(old)

Matrix Converter (new)


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Doubly Fed Induction Generator(DFIG) Wind- Energy Conversion

Institute of Energy Technology-Aalborg University: www.iet.aau.dk/education


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Mechanical Load Characteristics

, 1,0,2

k

rated

rated

nT C T k

n

; 2 / sec60

n

P T watts rad

( )rated rated T Load Torque at Rated Speed n

k Represents the Torque Dependency on Speedn Represents the Operating Speed in rpm

P Represents the Mechanical Power of the Load


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Speed

Torque

Constant Torque k=0

11T k

n

2 2T n k

Elevator


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IV (Induction)I (Synchronous)

II (dc Shunt/Separately excited)

III (dc series excited)

TmaxTorque

Speed

Various Motor Characteristics

Renewable Energy


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Renewable Energy

Solar

Tidal

Geothermal

The chart shows the length oftime that these remaining

reserves would last if

production continues at the

1996 level.

The Future of Energy

S t G id


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Smart Grid

Like the Internet, the Smart Grid will consist of

controls, computers, automation, and newtechnologies and equipment working together,but in this case, these technologies will workwith the electrical grid to respond digitally to

our quickly changing electric demand

http://www.smartgrid.gov/the_smart_grid

http://www smartgrid gov/the smart grid
http://www.smartgrid.gov/the_smart_gridhttp://www.smartgrid.gov/the_smart_gridhttp://www.smartgrid.gov/the_smart_gridhttp://www.smartgrid.gov/the_smart_grid


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Quicker restoration of electricity after power

disturbances Reduced operations and management costs

for utilities, and ultimately lower power costs

for consumers

Reducedpeak demand, which will also helplower electricity rates

Increased integration of large-scale

renewable energy systems

Better integration of customer-owner powergeneration systems, including renewable

energy systems

Improved security

http://www.smartgrid.gov/the_smart_grid
http://www.smartgrid.gov/the_smart_gridhttp://www.smartgrid.gov/the_smart_grid


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Smart Grid


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EE 303 Introduction 2013

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