Transcript ECE 310 - Cengage

Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
Chapter 1:
Introduction
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
Simple Power System
 Every power system has three major components
– generation: source of power, ideally with a
specified voltage and frequency
– load: consumes power; ideally with a constant
resistive value
– transmission system: transmits power; ideally as
a perfect conductor
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in
whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
Complications
 No ideal voltage sources exist
 Loads are seldom constant
 Transmission system has resistance, inductance,
capacitance, and flow limitations
 Simple system has no redundancy, so a power system will
not work if any component fails
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
Notation – Power
 Power: Instantaneous consumption of energy
 Power Units
Watts = voltage x current for dc (W)
kW
–
1 x 103 Watt
MW –
1 x 106 Watt
GW –
1 x 109 Watt
 Installed U.S. generation capacity is about
900 GW (about 3 kW per person)
 Maximum load of Champaign/Urbana about 300 MW
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
Notation – Energy
 Energy: Integration of power over time; energy is what
people really want from a power system
 Energy Units
Joule =
1 Watt-second (J)
kWh –
Kilowatt-hour (3.6 x 106 J)
 U.S. electric energy consumption is about 3600 billion
kWh (about 13,333 kWh per person, which means on
average we each use 1.5 kW of power continuously)
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
Power System Examples
 Electric utility: can range from quite small, such as an
island, to one covering half the continent
– there are four major interconnected ac power systems in
North American, each operating at 60 Hz ac; 50 Hz is
used in some other countries.
 Airplanes and Spaceships: reduction in weight is primary
consideration; frequency is 400 Hz.
 Ships and submarines
 Automobiles: dc with 12 volts standard
 Battery operated portable systems
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
North America Interconnections
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in
whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
Electric Systems in Energy Context
 Class focuses on electric power systems, but we first
need to put the electric system in context of the total
energy delivery system
 Electricity is used primarily as a means for energy
transportation
– Use other sources of energy to create it, and it is
usually converted into another form of energy when
used
 About 40% of US energy is transported in electric form
 Concerns about need to reduce CO2 emissions and fossil
fuel depletion are becoming main drivers for change in
world energy infrastructure
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whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
Sources of Energy – U.S.
About 86% Fossil Fuels
Biomass, 2.4
Other, 0.8
Hydro, 2.7
Nuclear, 8.1
CO2 Emissions (millions of
metric tons, and per quad)
Petroleum:
2598, 64.0
Natural Gas: 1198, 53.0
Coal:
2115, 92.3
Petroleum,
40.6
Natural Gas,
22.6
1 Quad = 293 billion kWh
(actual)
Coal, 22.9
1 Quad = 98 billion kWh
(used, taking into account
efficiency)
Source: EIA Energy Outlook 2007, Table 1, 2005 Data
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in
whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
Electric Energy by Sources, U.S.
Source: EIA State Electricity Profiles, 2006
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in
whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
Electric Energy by Sources, Calif.
Oregon is
71% Hydro,
while
Washington
State is
76% Hydro
Source: EIA State Electricity Profiles, 2006
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in
whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
Electric Energy by Sources, Illinois
Source: EIA State Electricity Profiles, 2006
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in
whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
Global Warming and the Power Grid
What is Known: CO2 in Air is Rising
Value was
about 280
ppm in 1800,
384 in 2007
Rate of
increase is
about 3 ppm
per year
Source: http://cdiac.ornl.gov/trends/co2/sio-mlo.htm
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in
whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
As is Worldwide Temperature
Baseline is 1961 to 1990 mean
Source: http://www.cru.uea.ac.uk/cru/info/warming/
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whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
Change in U.S.
Annual Average Temperature
[°C] = ([°F] - 32°) X 5/9
Source: http://www.sws.uiuc.edu/atmos/statecli/Climate_change/ustren-temp.gif
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whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
But Average Temperatures Are Not
Increasing Everywhere Equally
[°C] = ([°F] - 32°) X 5/9
Source : http://www.sws.uiuc.edu/atmos/statecli/Climate_change/iltren-temp.jpg
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in
whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
World Population Trends
Country
Japan
Germany
Russia
USA
China
India
World
2005
127.5
82.4
142.8
295.7
1306
1094
6449
2015
124.7
81.9
136.0
322.6
1393
1274
7226
2025
117.8
80.6
128.1
349.7
1453
1449
7959
%
-7.6
-2.1
-10.3
18.2
11.2
32.4
23.4
Source: www.census.gov/ipc/www/idb/summaries.html; values in millions;
percent change from 2005 to 2025
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whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
Eventual Atmospheric CO2
Stabilization Level Depends Upon CO2
Emissions
Regardless of what we do
in the short-term, the CO2
levels in the atmosphere will
continue to increase.
The eventual stabilization
levels depend upon how
quickly CO2 emissions are
curtailed.
Emissions from electricity
production are currently
about 40% of the total
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in
whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
Energy Economics
 Electric generating technologies involve a tradeoff between
fixed costs (costs to build them) and operating costs
– Nuclear and solar high fixed costs, but low operating
costs
– Natural gas/oil have low fixed costs but high operating
costs (dependent upon fuel prices)
– Coal, wind, hydro are in between
 Also the units capacity factor is important to determining
ultimate cost of electricity
 Potential carbon “tax” is a major uncertainty
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in
whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
Ball Park Energy Costs
Nuclear:
Coal:
Wind:
Hydro:
Solar:
Natural Gas:
$15/MWh
$22/MWh
$50/MWh
varies but usually water constrained
$150 to 200/MWh
8 to 10 times fuel cost in $/MBtu
Note: to get price in cents/kWh take price in $/MWh and
divide by 10.
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in
whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
Natural Gas Prices 1990s to 2008
1 dollar per million BTU = 3.41 dollars per megawatt-hour
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in
whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
Course Syllabus









Introduction and review of phasors & three phase
Transmission line modeling
Per unit analysis and change of base
Models for transformers, generators, and loads
Power flow analysis and control
Economic system operation/restructuring
Short circuit analysis
Transient stability
System protection
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in
whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
History of Electric Power Systems
 Early 1880s – Edison introduced Pearl Street dc system in
Manhattan supplying 59 customers
 1884 – Sprague produces practical dc motor
 1885 – invention of transformer
 Mid-1880s – Westinghouse/Tesla introduce rival ac system
 Late 1880s – Tesla invents ac induction motor
 1893 – First 3 phase transmission line operating at 2.3 kV
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in
whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
History, cont’d
 1896 – ac lines deliver electricity from hydro generation
at Niagara Falls to Buffalo, 32 km away
 Early 1900s – Private utilities supply all customers in
area (city); recognized as a natural monopoly; states step
in to begin regulation
 By 1920s – Large interstate holding companies control
most electricity systems
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in
whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
History, cont’d
 1935 – Congress passes Public Utility Holding Company
Act to establish national regulation, breaking up large
interstate utilities (repealed 2005)
 1935/6 – Rural Electrification Act brought electricity to
rural areas
 1930s – Electric utilities established as vertical monopolies
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in
whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
Vertical Monopolies
 Within a particular geographic market, the electric utility had
an exclusive franchise
Distribution
In return for this exclusive
franchise, the utility had the
obligation to serve all
existing and future customers
at rates determined jointly
by utility and regulators
Customer Service
It was a “cost plus” business
Generation
Transmission
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in
whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
Vertical Monopolies
 Within its service territory, each utility was the only game
in town
 Neighboring utilities functioned more as colleagues than
competitors
 Utilities gradually interconnected their systems so by
1970 transmission lines crisscrossed North America, with
voltages up to 765 kV
 Economies of scale resulted in decreasing rates, so most
every one was happy
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whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
Current Midwest Electric Grid
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in
whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
History, cont’d – 1970s
 1970s brought inflation, increased fossil-fuel prices, calls
for conservation and growing environmental concerns
 Increasing rates replaced decreasing ones
 As a result, U.S. Congress passed Public Utilities Regulator
Policies Act (PURPA) in 1978, which mandated utilities
must purchase power from independent generators located
in their service territory (modified 2005)
 PURPA introduced some competition
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in
whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
History, cont’d – 1990s & 2000s
 Major opening of industry to competition occurred as a
result of the National Energy Policy Act of 1992
 This act mandated that utilities provide “nondiscriminatory”
access to the high voltage transmission
 Goal was to set up true competition in generation
 Result over the last few years has been a dramatic
restructuring of electric utility industry (for better or worse!)
 Energy Bill 2005 repealed PUHCA; modified PURPA
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in
whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
Utility Restructuring
 Driven by significant regional variations in electric rates
 Goal of competition is to reduce rates through the
introduction of competition
 Eventual goal is to allow consumers to choose their
electricity supplier
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in
whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
State Variation in Electric Rates
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whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
The Goal: Customer Choice
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whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
The Result for California in 2000/1
OFF
OFF
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whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
The California-Enron Effect
WA
MT
ND
MN
OR
ID
SD
WY
NV
WI
CA
CO
PA
IL
KS
AZ
OK
NM
NY
MI
IA
NE
UT
VT ME
MO
AR
IN OH W
KY
TN
MS AL
TX
VA VA
N
H
MA
RI
CT
NJ
DE
D
M
C
D
NC
SC
GA
LA
AK
FL
HI
electricity
restructuring
delayed
restructuring
no activity
suspended
restructuring
Source : http://www.eia.doe.gov/cneaf/electricity/chg_str/regmap.html
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in
whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
August 14, 2003 Blackout
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whole or in part.
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Power System Analysis and Design, SI, 6e
Glover, Overbye, Sarma
2007 Illinois Electricity Crisis
 Two main electric utilities in Illinois are ComEd and
Ameren
 Restructuring law had frozen electricity prices for ten
years, with rate decreases for many.
 Prices rose on January 1, 2007 as price freeze ended;
price increases were especially high for electric heating
customers who had previously enjoyed rates as low as
2.5 cents/kWh
 Current average residential rate (in cents/kWh) is 10.4 in
IL, 8.74 IN, 11.1 WI, 7.94 MO, 9.96 IA, 19.56 CT, 6.09
ID, 14.03 in CA, 10.76 US average
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in
whole or in part.
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