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ECE 476
POWER SYSTEM ANALYSISLecture 1
Alejandro D. Dominguez-Garcia
aledan@ILLINOIS.EDU
Material borrowed from Prof. George Gross
OUTLINE
The importance of electricity
The US electricity industry – past and present
Electricity generation
Nature of electric demand
The energy supply and demand picture
A brief overview of renewables
CRITICAL IMPORTANCE OF ELECTRICITY
Energy is the lifeblood of modern society
The importance of electricity is on the rise, e.g.,
electrification of transportation
Efficient and environmental electricity services
are key or the nation’s global competitiveness
Electricity is a $247 billion plus business annually
in the U.S.
U.S. ENERGY AND ELECTRICITY DEMAND
0
50
100
150
200
250
300
1980 1990 2000 2004 2010 2020 2030
CO2 emissionselectricity use
energy use
1980 = 100%
historical forecast
A VIEW OF THE POWER GRID
“I worked on aerospace problems for many years before converting to power systems, and, in my opinion at least, power problems are tougher in many respects....The number of variables [in a power system] is huge, and many types of uncertainties are present....Few if any aerospace problems yield such a challenging set of conditions.”
– Fred. C. Schweppe, 1970
Fred C. Schweppe (1934-1988)Professor of Electrical Engineering, MIT US Power grid
IMPACTS OF ELECTRICITY
The National Academy of Engineering, the U.S.’s
most prestigious collection of outstanding
engineers, named electrification – the
development of the vast networks of electricity
that power the world – the most important of the
twenty engineering achievements that have had
the greatest impact on the quality of life in the
twentieth century
IMPACTS OF ELECTRICITY
Electricity ranked ahead of the automobile,
airplane, safe and abundant water, electronics,
computers and space exploration
The widespread electrification implemented in
the twentieth century gave us power for our
cities, factories, farms and homes, forever
changing the lives of people
OUTLINE
The importance of electricity
The US electricity industry – past and present
Electricity generation
Nature of electric demand
The energy supply and demand picture
A brief overview of renewables
Commercial use of electricity began in the late
1870’s with the development of arc lamps for
street lighting and lighthouse illumination
The first complete electric power system,
comprising a generator, cable, fuse meter and
loads, is considered to be Edison’s Pearl Street
Station in New York in 1882
DC system with a DC generator supply
59 customers in a 1 mile radius area
THE BEGINNINGS
1882 EDISON POSTER ON ELECTRIC LIGHTING
You can find this plate in the washrooms of the Courier Café in downtown Urbana.
THE BEGINNINGS
Actually, George Roe had founded in 1879 an
electric company in San Francisco, which later
became part of PG&E
the first plant in the nation to offer central
station electric service to the public
two brush arc-light dynamos supplied 21 lights
for service from sundown to midnight –
Sundays and holidays excluded – for $ 10 per
lamp per week
Frank Sprague developed electrical motors in 1884;
within a short time, he incorporated them into the
electricity system
The major limitations of DC systems became
apparent by 1886:
ability to deliver power over only short
distances
need for high voltages for longer distance
transmission; such voltages were too high for
generation and consumption
MAJOR DEVELOPMENTS
Gaulard and Gibbs developed the transformer and
AC transmission, the forerunners of the AC
transmission systems in use today
George Westinghouse bought U.S. rights
immediately to the technological developments of
Gaulard and Gibbs
In 1889, the first AC transmission line in North
America was put into operation between
Willamette Falls and Portland – a single phase
4–kV 21–km line
MAJOR DEVELOPMENTS
A major important development was Tesla’s
invention of induction motors and polyphase
systems
Westinghouse purchased the rights to Tesla’s
inventions on AC motors, generators,
transformers and transmission systems
Westinghouse was instrumental in the
construction of the basis of today’s AC grid
MAJOR DEVELOPMENTS
AC won out over DC because
the ease of transformation of voltage levels
thereby providing the flexibility of using
different voltage levels for generation and
transmission consumption
the increased simplicity of AC over DC
generators
the increased simplicity and lower costs of AC
over DC motors
AC replaced DC over a very brief time period
MAJOR DEVELOPMENTS
In 1893, the first three–phase transmission line in
North America went into service; it was a 2.3–kV,
12–km line in Southern California
Niagara Falls was connected to Buffalo – a 30–km
distance – using AC since DC was not practical
MAJOR DEVELOPMENTS
Pressures to transmit larger amounts of power
over larger distances led to higher voltages early systems: 12, 44 and 66 kV (RMS line–to–
line) 1922: 165 kV 1923: 220 kV 1935: 287 kV 1953: 330 kV 1965: 500 kV 1966: 735 kV (Hydro Quebec) 1969: 765 kV (American Electric Power)
TECHNOLOGICAL DEVELOPMENTS
Standardization of voltage levels led to voltage
classifications
115, 138, 161 and 230 kV are high voltage ( HV )
345, 500 and 765 kV are extra high voltage ( EHV )
The development of mercury arc valves in the
early 1950’s makes HVDC economical in specific
cases: transmission of larger blocks of power over
longer distances
TECHNOLOGICAL DEVELOPMENTS
Eventually, the various frequencies in use – 25,
50, 60, 125 and 133 Hz – standardized to 60 Hz in
North America; there are many parts of the world
where the frequency is 50 Hz today
DC becomes economic over AC for distances
greater than
500 km for overhead lines
50 km for underground/submarine cables
TECHNOLOGICAL DEVELOPMENTS
Legend
Cooperatives
Federal
Independent Transmission Companies
Other Public Power
Shareholder-Owned
ELECTRIC TRANSMISSION LINES IN THE U.S.
Copyright 2003 Edison Electric Institute. Source: POWERmap, © Platts, a Division of the McGraw Hill Companies. 20
INDUSTRY STRUCTURE
Brutal and inefficient competition was rife in
electricity
24 central station power companies were
established in Chicago between 1887 and 1893
exhaustive duplication and fierce competition
led to high costs
INDUSTRY STRUCTURE
Samuel Insull built a monopoly over all central
station production in Chicago and is considered
the father of the regulated monopoly:
“exclusive franchises should be coupled with
the conditions of public control, requiring all
charges for services to be based on a cost
plus a reasonable profit”
In 1907, New York and Wisconsin set up commis–
sions to regulate electricity
customers
self-generation
Independentpower producers
THE VERTICALLY INTEGRATED UTILITY INDUSTRY STRUCTURE
Generation
Transmission
Distribution
Customer Service customer service
distribution
transmission
generation
COMPETITION IN THE GENERATION MARKET
The 1978 Public Utility Regulatory Policies Act (PURPA) unleashes competition through the introduction of qualifying facilities (QFs)
PURPA mandates each investor–owned utility to purchase power at avoided cost from QFs located in its service territory
Implementation of PURPA was left to individual states resulting in non-uniform implementations
The once fledgling private power enterprises constitute today a multibillion dollar industry whose role in the electricity business is critically important
Source :Energy Information Administration, Existing Electric Generating Units in the United States, Source :Energy Information Administration, Existing Electric Generating Units in the United States, 20052005
ENERGY SOURCES OF NON UTILITY GENERATION (NUG) CAPACITY
coal 17.8%
nuclear 8.3%
oiloil 5.75.7%%
otherother 3.13.1%%
hydrohydro 2.12.1%%
windwind 1.71.7%%
waste waste 1.51.5%%geothermal geothermal 0.70.7%%
natural gas natural gas 59.059.0%%
INCREASING ROLE OF NUG
Source : EIA, Net Generation by Energy Source by Type of Producer, 2006
non-utility utility
bill
ion
k
Wh
0
1000
2000
3000
4000
5000
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
120.76
0.00116.87
0.730
20
40
60
80
100
140
residential
commercial
industrial
other
U.S. ELECTRICITY CUSTOMERS
total consumers = 138.4 million
mill
ion
co
nsu
mer
s
Source : Energy Information Administration, Form EIA-861, “Annual Electric Utility data” released November 2006
120
US ELECTRICITY SALES IN 2005
total sales: 3,660 million MWh
total revenues: $ 228 billion
residential1,356 TWh
industrial1,275 TWh
commercial1,019 TWh
other7.5 TWh
residential$ 128 billion
industrial$ 110 billion
commer-cial $ 58
billion
other$ 0.6 billion
Source : Energy Information Administration, Form EIA-861, “Annual Electric Utility data” released November 2006
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