Power System Analysiscourse.sdu.edu.cn/Download2/20150921174712451.pdfPower System Analysis for Graduates 3 Instuctor: Prof. Wen Zhang 1992.7-1995.7 T.A., Shandong University of Technology

2015/9/21

Power System Analysisfor Graduates

Backgrounds

Dr. Changgang Li

Email: [email protected]

Work: 81696140

Power System Analysis for Graduates 22

Instuctor: Dr. Changgang Li

2002.9-2006.7 B.S., Electrical Engineering, SDU

2006.9-2012.7 Ph.D., SDU (Supervisor: Dr. Yutian Liu)

2012.5-2014.5 Postdoc, UTK (Supervisor: Dr. Yilu Liu)

2014.5-now Associate Research, SDU

Contacts:

[email protected]

81696140/13573101895

Wechat: changgang_li

Office: EE310


Instuctor: Prof. Wen Zhang

1992.7-1995.7 T.A., Shandong University of Technology

1995.7-2000.7 Lecturer, Shandong University of Technology

2000.7-2007.9 Associate Professor, SDU

2007.9-2008.9: Visiting Scholor, University of Wisconsin

2007.10-now Professor, SDU

Contacts:

[email protected]

81696305/18660778166

Office: 5-319


Course

This course will cover fundamentals of electric power systems, including basic principles, modeling of generators, transformers and transmission lines, power flow, fault analysis, stability, and control problems.

Students will learn both modeling of power systems and numerical solutions to the powerflow, fault and stability problems. Basic control of active and reactive powers, small-signal stability, transient stability and voltage stability will be discussed.

There will be moderate work of programming in MATLAB or using professional power system simulation software for power system studies.

Students are also encouraged to review literature on recommended topics to gain broader knowledge on, e.g., renewable energy resources and emerging smart grid techniques.


Textbook

J. D. Glover, M. S. Sarma, and T. J. Overbye, Power System Analysis and Design (5th edition), Nelson Education, Ltd, 2012 (main textbook)

A. Bergen and V. Vittal, Power System Analysis, Prentice Hall, 2000.

H. Saadat, Power System Analysis (3rd edition), McGraw-Hill, 2010


Course Outline

Backgrounds (1)

Modeling of power system devices (3)Generator, transformer, transmission line, HVDC

Powerflow (3)Modeling, Newton-Raphson Solution, advanced solutions

Introduction to PSS/E (1)

Stability (3)

Control of frequncy and voltage(3)


Backgrounds outline

History of elctric industry

Introduction to electric power systemsEnergy resources, grid operation


Some big names of the field of electricity

Big Names (Ordered by DOB) Achievements

Benjamin Franklin (1706-1790 ), American Lightning rod, Charge conservation

Charles A. de Coulomb (1736-1806), French Coulomb's law

James Watt (1736-1819), Englishman Steam engines, concept of power

Count A. Volta (1745-1827), Italian Battery

Andre M. Ampere (1775-1827), Frenchman Electromagnetism, Ampere s law,

Hans C. Orsted (1777-1851), Danish Electromagnetism

Carl F. Gauss (1777-1855), German Gauss's law

George S. Ohm (1789-1854), German Ohm's law

Michael Faraday (1791-1867), Englishman Electromagnetic induction

Joseph Henry (1797-1878), American Self- and mutual- inductance

James P. Joule (1818-1899), Englishman Energy, Joule's first law

Gustav R. Kirchhoff (1824-1889), Prussian/German Kirchhoff's circuit laws

James C. Maxwell (1831-1879), Scotsman Electromagnetic field, Maxwell's equations

George Westinghouse (1846-1914), American AC power system

Thomas A. Edison (1847-1931), American Incandescent light bulb, DC power system

Nikola Tesla (1856-1943), Croatian/American AC induction motor & transformer, AC power system

Heinrich Hertz (1857-1894), German Electromagnetic waves

William Stanley, Jr. (1858-1916), American New transformer design still used today, other devices

Charles P. Steinmetz (1865-1923), German/American Mathematical theories for AC systems


1831: World's 1st electric dynamo by Faraday

August 29, 1831: Faraday demonstrated how to make electricity from a change in magnetism


1876: World s 1st R&D Lab by Edison

Started in 1876 at Menlo park, NJ.

The Laboratory buildings were removed in 1929 by industrialist Henry Ford to his Greenfield Village Museum in Dearborn, Michigan


1879: 1st Commercially Practical Incandescent Light by Edison

First successful light bulb

model, used in public

demonstration at Menlo

Park, December 1879

(source: Wikipedia.org)

Edison and his Menlo Park crew (taken

in 1880, i.e. soon after new lights were

installed)


1882: 1st Commercial Power Plant for a City by Edison

Three floors of Pearl Street Generation Station in NYC (commissioned on Sept. 4,

1882)

–It had six coal-fed steam locomotive engines powering six direct current dynamos

–Served 59 customers (all incandescent lamps at 110V through underground

cables) within a 1.5km radius area. (Motor loads were added to such systems after

1884)


By the time Edison was in his mid-30s, he was said to be the best-known American in the world

Edison has more patents (1,093) in his name than any other person, including:389, Electric Light & Power

195, Phonograph

150, Telegraph

141, Storage Batteries

34, Telephone

Kinetograph Motion Camera

Kinetoscope Motion Viewer

Magnetic Ore Separator


1st home to be lit by electricity

J.P. Morgan - Financial backer of Edison Electric Light Co., which later became General Electric Co.

J.P. Morgan s home was the first home to be lit by electricity using Edison s new electric light bulbs, powered by an Edison DC dynamo in Morgan s home basement.


Nikola Tesla

Rotating Magnetic PrincipleAC Induction Motor

Tesla High Voltage Coil

700 Other Patents

This publicity photo taken at

Colorado Springs was a double

exposure (1899). Tesla posed with

his "magnifying transmitter" capable

of producing millions of volts of

electricity. The discharge shown is

twenty-two feet in length.

Nikola Tesla (by David

Bowie) in movie The Prestige

(2006) (Source: IMDb.COM)

Polyphase AC Generators, Motors, and Grid Equipment

Practical Wireless Communication

Telephone Repeater


George Westinghouse

An entrepreneur having the ability to transform new ideas to commercial reality while allowing for relatively simple maintenance practicesInvented railroad air brake and signaling

equipment; had many patents on natural gas

piping systems & equipment

Bought numerous electricity patents from Tesla

Commercialized AC generation & transmission

systems

Battled Edison over AC vs. DC

Generation & grid applications

When Tesla needed money, Westinghouse paid

for Tesla s room & board at the Waldorf Astoria,

NY City


Westinghouse-Tesla Polyphase Exhibit:The Chicago World's Fair (1893)

Westinghouse s AC bid won

over GE s DC bid for the fair s

power & lighting contract.


1st Westinghouse Generator

One of the 1st Westinghouse Niagara

Falls Power Company generators

being built in Pittsburgh in 1894

First Three Westinghouse Generators in

Stanford White's "Cathedral of Power"

at Niagara Falls (photo taken April 6,

1896)

Most of the

patents

cited right

were from

Tesla


Morgan and Tesla

In 1900 Morgan invested $150,000 in Nikola Tesla's Wardenclyffe Tower, a high

power transatlantic radio transmission project.

By 1903 Tesla had spent the initial investment without completing the project,

and with Guglielmo Marconi already making regular transatlantic transmissions

with far less expensive equipment, Morgan declined to fund Tesla any further.

Tesla tried to generate more interest in Wardenclyffe by revealing its capability

of wireless electricity transmission, but the loss of Morgan as a backer, and the

later 1907 financial crisis dried up any further investment

In 2007, a MIT group powered a 60W bulb WIRELESSLY

over 7 feet in the air between two coils resonating together

at 9.9MHz. (for more information search for keyword

WiTricity )

Wardenclyffe Tower (1901–1917)


From Generator to Grid

William Stanley, Jr, had 129 Patents,

including:

–Transformer (new design still used

today)

–Inductor Alternator

–Line Insulator

–Line Switch

–Vacuum (Thermos) Bottle

Charles Steinmetz

–A mathematician who invented AC

system theories (e.g. on hysteresis,

steady-state analysis and transients)

for AC machine and network

performance calculations

–Recognized as one of the great

inventors and minds of the 1900 s.


Reasons for AC Winning over DC

Voltage levels can be easily transformed in AC systems, thus providing the flexibility for use of different voltages for generation, transmission and consumption

To reduce transmission power losses (I2R) and voltage drops, voltage levels have to be high for long-distance power transmission. HVAC was easier to implement by means of transformers. (At present, the cross-over point for HVDC to be competitive is around 500km for overhead lines or 50km for underground/submarine cables.)

AC generators and motors are much simpler than DC generators and motors (commutators needed)


How Transformers Work?

V2 can be larger or smaller than V1

It only works with AC!


Why 3-phase AC?

Generation and transmission adopt 3-phase because:3 wires for 3 loads (if balanced)

Power in 3-phase AC is constant, not in pulses as in 1-phase AC. Thus, more power is delivered and 3-phase motors run more smoothly


1st 100 Years of Electric Industry

1882: Pearl Street Station, the 1st DC system by Edison, operated in NYC

1886: Commercially practical transformer and AC distribution system developed by Stanley

1888: Development of poly-phase AC by Tesla started AC vs. DC battle

1889: 1st AC transmission line in the US (1-phase, 21km at 4kV in Oregon)

1893: 1st 3-phase line (2.3kV, 12 km by SCE) in North America; AC vs. DC battle ended when AC was chosen at Niagara Falls.

1912-1923: 1st 110kV and 220kV HVAC overhead lines

1950s: 345kV-400kV EHV AC lines by USA, Germany and Sweden

1954: 1st modern commercial HVDC transmission (96km submarine cable) in Sweden.

1960s: 735-765kV EHV AC in Russia, USA and Canada

1972: 1st thyristor based HVDC Back-To-Back system between Quebec and New Brunswick in Canada


AC/DC Hybrid:


Energy Resources for Electricity Generation


Fossil Fuel Power Plants

Coal-fired steam turbine power plant(Rankine Cycle)


Coal-fired steam turbine power plant

Energy flowBoiler burns pulverized coal to

produce high P&T steam

Turbines (HP, MP, and LP) convert

heat of flowing steam to mechanical

energy to spin a generator

Generator converts mechanical

energy to electric energy

ConcernsLow efficiency (<45%)

Environmental concerns

major emitters of CO2


Gas turbine power plant (Brayton Cycle)

A gas turbine is also called combustion turbine and operates like a jet engine

Efficiency ~ 46%

Start quickly in minutes (used for peak load)

Usually used in conjunction with a heat recovery system generator (HRSG) for a combined-cycle or co-generation power plant.


Combined-cycle power plant

Higher overall efficiency (>60%)

Brayton Cycle

+

Rankine Cycle


Nuclear Power Plants

Steam power plant except that the boiler is replaced by a nuclear reactor, e.g. BWR (boiling-water reactor) and PWR (pressurized-water reactor)

Effociency ~ 30%


Hydroelectric Power Plants

Generated electric power

~0.85


Types of Hydro Plants

Run-of-the-river hydro plantsUse the nature flow of rivers

Cheap; very little environmental impact

Power outputs may have seasonal fluctuations

Pumped-storage hydro plantsTypically have two reservoirs at two elevations

Energy storage function (accounts for >99% of bulk storage): during off-peak times, the generator can operate as a synchronous motor (pump) to save surplus electricity by elevating water

Brought to full power within a few minutes from startup (important for grid stability in, e.g. backing up wind/solar power generation)


Solar Power

Photovoltaic (PV)Photoelectric effect: Light->electricity

h ~ 15%

Concentrated solar power (CSP)Light->heat->electricity

Parabolic Troughs

Parabolic dish concentrators (Dish Stirling, h~30%)

Solar Tower


Annual radiation power


Wind Power Plants

Generated electric power

v(m/s)

A(m2)


Wind power


Types of wind power plant

OnshoreCloser to existing electrical grids

More noise and visual pollution

Limited land sites

OffshoreHigher investment and maintenance costs

Less noise

Huge resources; higher and more stable wind speed


Wind Turbines

Doubly-Fed Induction Generators (DFIG)Most commonly used

Double fed : energy is delivered to the grid from both the stator and the rotor

The power electronic converters enable DFIG to operate at the optimal rotor speed and to maximize power generation by controlling the active and reactive power injected into the grid at a constant voltage frequency.


Reliability Concerns in Integration of Wind Generation

Inaccuracy in short-term wind forecast

Supply-demand mismatch


Other Clean Energy Resources

Geothermal Power PlantsUtilize heat within the earth, usually in the form of underground steam or hot water

Biomass Power (Biopower) PlantsCombustion of plants, agricultural residues and other wastes to generate electricity

Causes zero net increase in CO2

Tidal Power PlantsCapturing potential/kinetic energy of tides caused by the gravitational pull from the moon (twice a day)

Fuel CellConvert chemical energy into electricity


Question

Which of these generation resources utilize steam turbines in generating electric power?Coal-fired power plant

Combined-cycle power plant

Parabolic Trough

Solar Tower

Pressurized water reactor

Geothermal power plant


Structure of an AC Power System

GenerationLow voltages <25kV due to insulation requirements

Transmission systemBackbone system interconnecting major power plants (11~35kV) and load center areas

Sub-transmission systemTransmitting power to distribution systems

Distribution system


China UHV power grid by 2020


U.S. power grid


De-regulation: Competitive Power Market Structure

Regulation: the government sets down laws and rules that put limits on and define how a particular industry or company can operate.

De-regulation:Infrastructure was builtMonopolies are inefficient: high operation costs, no penalty for mistakes, not customer-focusedWell-developed generation technologiesMarket-driven, complying with reliability standardsTypically, bid-based, security-constrained, economic dispatch with nodal prices.


U.S. Electric Power Markets (ferc.gov)


Power Blackouts of in North America

Date Area Impacts Duration

9-Nov, 1965North America (NE)

20,000+MW, 30M people

13 hrs

13-Jul, 1977North America (NY)

6,000MW, 9M people

26 hrs

22-Dec, 1982North America (W)

12, 350 MW, 5M people

Jul 2-3, 1996North America (W)

11,850 MW, 2M people

13 hrs

10-Aug, 1996North America (W)

28,000+MW, 7.5M people

9 hrs

25-Jun, 1998North America (N-C)

950 MW, 0.15M people

19 hrs

14-Aug, 2003North America (N-E)

61,800MW, 50M people

2+ days

8-Sep, 2011US & Mexico (S-W)

4,300MW, 5M people

12hrs

1965

1977

2003


System Control Centers


Smart Grid

May be defined as a broad range of solutions that optimize the energy value chain. It brings the power of networked, interactive technologies into an electricity system to improve reliability, security and efficiency of the electric system.Digitalized, Interactive, Sustainable, Resilient, Robust, Autonomous and Efficient.

http://smartgrid.epri.com/Demo.aspx

Variable distributed

energy resources

Smart commercial

buildings

Smart industry

buildings

Smart

residential

buildings


Q&A


Homework

Review Ch. 2: Fundamentals

Review Ch. 4&5: Transmission line

Documents

Power System Analysiscourse.sdu.edu.cn/Download2/20150921174712451.pdfPower System Analysis for Graduates 3 Instuctor: Prof. Wen Zhang 1992.7-1995.7 T.A., Shandong University of Technology