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"Time"Time--Varying Power Quality Issues:Varying Power Quality Issues:
An Overview of Advanced Modelling /An Overview of Advanced Modelling /Simulation and Control Approaches,Simulation and Control Approaches,Applications and Solutions"Applications and Solutions"
Dr. Paulo RibeiroDr. Paulo Ribeiro
Dr. Siddharth Suryanarayanan,Dr. Siddharth Suryanarayanan, JinglinJinglin XuXu, Dr. Michael Steurer,, Dr. Michael Steurer,Dr.Dr. SanjeevSanjeev SrivastavaSrivastava, Dr. David, Dr. David CartesCartes, and Dr. Steve Woodruff, and Dr. Steve Woodruff
Department of Engineering, Calvin College, Grand Rapids, MI 4954Department of Engineering, Calvin College, Grand Rapids, MI 49546.6.
CenterCenterfor Advanced Power Systems, Florida State University, Tallahassfor Advanced Power Systems, Florida State University, Tallahassee, FL 32310.ee, FL 32310.
May 21rstto 25th 2006FLORIANPOLIS (SC) BRASIL
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Vision (Strategy)Vision (Strategy)
RulesRules(Physical, Economics, and Business Imperatives and(Physical, Economics, and Business Imperatives and
Constraints)Constraints)
Road MapRoad Map(How Things Should Work to Bring Us to the Destination)(How Things Should Work to Bring Us to the Destination)
Man Has Three Sources of Information(To Guide His Path)
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SummarySummary -- OutlineOutline
This presentation provides an overview of theThis presentation provides an overview of thetimetime--varying power quality issues in powervarying power quality issues in powersystems.systems.
The phenomenon of time varying power qualityThe phenomenon of time varying power qualityis described and the various types of analyticalis described and the various types of analytical
and visualization tools available.and visualization tools available. Several examples of current research in the fieldSeveral examples of current research in the field
with emphasis on real time digital simulation,with emphasis on real time digital simulation,
hardware in the loop concept, active filtering,hardware in the loop concept, active filtering,other power electronic control concepts and useother power electronic control concepts and useof advanced signal processing tools such asof advanced signal processing tools such aswavelet transforms and Swavelet transforms and S--transform, andtransform, and
intelligent techniques such as fuzzy logic areintelligent techniques such as fuzzy logic areprovided.provided.
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The Big Picture
Tools Enabling
Reality Technique F Domain
Time Frequency
Time-Frequency
Evolutionary Spectrum
Probability
Spectral
Fourier
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Equipment designer or manufacturer: a perfect
sinusoidal wave, with no variations in the voltage,and no noise present on the grounding system.
Electrical utility: voltage availability or outage.
Industrial / end-user: the power that works for
whatever equipment the end-user is applying.
While each hypothetical point of view has a clear difference, it is
clear that none is properly focused.
The Bigger PictureThe Bigger Picture
What is Power Quality (Different Perspectives)?What is Power Quality (Different Perspectives)?
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What is Power Quality (Different Deviations)?
The Bigger PictureThe Bigger Picture
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What is Power Quality (Different Deviations)?
The Bigger PictureThe Bigger Picture
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Power Quality (Incompatibility) Problems and Solutions
Distributed Generation / Resources
Advanced Compensation Devices / PE Technologies
Intelligent Control and Protection Technologies
New Management Structures
Increased Equipment Sensitivity
Advanced Signal Processing / Intelligent IdentificationTechniques for Analysis and Diagnostic
Advances in Modeling and Simulation particularly related to
Visualizations, and Time-Varying Waveform Distortions
AnalysisReal Time Digital: Hardware-in-the-Loop
What is Power Quality
(Different Aspects and New Issues)?
The Bigger PictureThe Bigger Picture
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Hospital withcogeneration (1.5 MW)
SubstationFeeder
Residentialphotovoltaic system (6
kW)
Utility-ownedPhotovoltaic site (500
kW)
Small wind turbine (10kW)
Factory with natural gas fuelcell (100 kW to 5 MW)
Residential Fuelcell (7 kW)
Utility-owned wind turbine
site (1 MW)
With permission of M. McGranaghan, and T. Key
What is Power Quality (New Topologies and Technologies)?
The Bigger PictureThe Bigger Picture
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Generation
Transmission
Performance Parameters
Planning
Operation
Economic Feasibility
Distribution
Power Quality (The Economics Perspective)?
The Bigger PictureThe Bigger Picture
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Accessibility
Security
Continuity
Reliability
Voltage (Power) Quality
Performance Parameters
The Bigger PictureThe Bigger Picture
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Special (Traction) LoadsSpecial (Traction) Loads
Electrification of CarajElectrification of Carajs Railways Railway(892Km(892Km 230/25/50kV). 76/77.230/25/50kV). 76/77.
Unbalance,Unbalance,
Voltage Fluctuations andVoltage Fluctuations andHarmonic DistortionHarmonic Distortion
The Bigger PictureThe Bigger Picture
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Harmonic Distortion onHarmonic Distortion onthe Transmission Gridthe Transmission Grid
Caused by:Caused by:
TV Receivers)TV Receivers)
Harmonic DistortionHarmonic Distortion
MeasurementsMeasurements -- 230kV230kV
SubstationSubstation -- During WorldDuring World
Cup Soccer GameCup Soccer Game
Fortaleza, Brazil, June 1986Fortaleza, Brazil, June 1986
Brazil 2 X 0 IrelandBrazil 2 X 0 Ireland
Measurement
Point
The Bigger PictureThe Bigger Picture
(World Cup Soccer and Harmonic Distortion)(World Cup Soccer and Harmonic Distortion)
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Summary of the MeasurementsSummary of the Measurements
55thth Harmonic VoltageHarmonic Voltage 230kV Bus230kV Bus
Match Time
The Bigger PictureThe Bigger Picture
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Voltage at the 230kVVoltage at the 230kV -- Detail of 13.2kV Residential FeederDetail of 13.2kV Residential Feeder
Disconnection (before the beginning of the match)Disconnection (before the beginning of the match)
Clearly indicates the origin the
harmonic source / contribution
to the 5th harmonic distortion
on the 230kV bus.
Led to Flexibility and
Higher Tolerance
The Bigger PictureThe Bigger Picture
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Distorted TimeDistorted Time--Varying WaveformsVarying Waveforms
is the Normis the Norm
138kV bus voltage THD
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0
20
40
60
80
100
120
PQ Disturbance
Power Outage
Cost of Power Outages and PQ Disturbances by Business SectorCost of Power Outages and PQ Disturbances by Business Sector
Total AnnualCost of Power
Outages and PQ Disturbancesby Business Sector
Cost of:
$14.3
$6.2
$34.9
$66.6-135.6
Source: Primen Study: The Cost of Power Disturbances to Industrial & Digital Economy Companies
DigitalEconomy
ContinuousProcess
Mfg.
Fabrication& Essential
Services
Other USIndustry
$Billion
TOTAL$119 - $188 Billion
40% GDP 60% GDP
The Biggest PictureThe Biggest Picture
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The Detail (Road Map) Picture
Combining Spectral and Probabilistic AnalysisHow can time-varying harmonic distortion be understood and analyzed from a
more mathematically precise perspective?
Based on some previous mathematical derivations and analysis it has been
observed:
1 - Similarity between spectral analysis and probability distribution functions
2 - The concept of generalized frequency
3 - The concept of evolutionary spectrum
10 1000
5
1010
0
ftj
10010 jContinuous Spectrum of a Non-Periodic
Waveform
30 20 10 0 10 20 300
5
1010
0
f
29.88329.883
lower upper
int
Probability Distribution Function of a
Non-Stationary Process
10 1000
5
1010
0
ftj
10010 j
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The Generalized Concept of Frequency
Suppose that X(t) is a deterministic function which has the form of adamped sine wave below and illustrated below.
X t( ) A e
t
2
2
cos 0 t +( )
40
40
vi
20 i
128
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100 50 0 50 100 1500
56
0
ftj
ftj
128128 j
FFT of X(t)
If we represent X(t) as a sum of sine and cosine functions with constant
amplitudes, we need to include components at all frequencies. However, we can
equally well describe X(t) by saying that it consists of two "frequency"
components, each having a time varying amplitude of
A e
t2
2
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Generalized FrequencyGeneralized Frequency
If we have a nonIf we have a non--periodic function X(t)periodic function X(t)
whose Fourier transform has an absolutewhose Fourier transform has an absolutemaximum at a point w0, we may define w0maximum at a point w0, we may define w0
as "the frequency" of this function, theas "the frequency" of this function, the
argument being that locally X(t) behavesargument being that locally X(t) behaves
like a sine wave with conventionallike a sine wave with conventional
frequency w0, modulated by a "smoothlyfrequency w0, modulated by a "smoothlyvarying" amplitude frequency.varying" amplitude frequency.
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The Concept of Evolutionary SpectrumThe Concept of Evolutionary Spectrum
Whereas the spectrum of a stationary process describes theWhereas the spectrum of a stationary process describes thepowerpower--frequency distribution for a whole process (over allfrequency distribution for a whole process (over all
time), the evolutionary spectrum is time dependent andtime), the evolutionary spectrum is time dependent anddescribes the local powerdescribes the local power--frequency distribution at eachfrequency distribution at eachinstant of time.instant of time.
The theory of evolutionary spectra is the only one which canThe theory of evolutionary spectra is the only one which can
preserve the physical interpretation for nonpreserve the physical interpretation for non--stationarystationaryprocesses.processes.
The evolutionary spectrum is a continuously changingThe evolutionary spectrum is a continuously changingspectrum or in other words, a timespectrum or in other words, a time--dependent spectrum.dependent spectrum.
It is not practical to estimate the spectrum at every instant ofIt is not practical to estimate the spectrum at every instant oftime. But if we assume that the spectrum is changingtime. But if we assume that the spectrum is changingsmoothly over time then, by using estimates which involvesmoothly over time then, by using estimates which involveonly local functions of the data, we may attempt to estimateonly local functions of the data, we may attempt to estimate
some form ofsome form ofaverageaverage spectrum of the process in thespectrum of the process in theneighborhood of any particular time instant.neighborhood of any particular time instant.
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The Concept of Evolutionary SpectrumThe Concept of Evolutionary Spectrum
Using the concept of evolutionary spectrum oneUsing the concept of evolutionary spectrum onecan confidently say that the behavior aroundcan confidently say that the behavior around
these two frequencies at a certain instant in timethese two frequencies at a certain instant in time
is sinusoidal can could linear summation methodsis sinusoidal can could linear summation methods
could be applied. At other frequencies the level ofcould be applied. At other frequencies the level of
confidence and meaning of the results are not beconfidence and meaning of the results are not betrusted.trusted.
50 100 150 200 250 3000
1
22
0
ftj
25610 j
1.191
0.896
vi
10 i
N
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The Concept of Evolutionary SpectrumThe Concept of Evolutionary Spectrum
Applied to timeApplied to time--varying harmonic distortionvarying harmonic distortion
seems a useful approach, and may help theseems a useful approach, and may help the
power quality engineer to better understand thepower quality engineer to better understand the
nature of such variations and properly utilizenature of such variations and properly utilize
analytical tools to predict their behavior.analytical tools to predict their behavior.
Further investigations and applications usingFurther investigations and applications using
practical waveforms together with fieldpractical waveforms together with fieldmeasurements are necessary to validate thismeasurements are necessary to validate this
approach.approach.
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Differentiating Between Transients and Harmonics
A proposed new definition:
Transient event: A power system event that has significant short term
impacts on voltages and currents in the system.
Transient: The short term voltages and currents resulting from a transientevent, which are superimposed on the longer term system voltages and
currents.
Figure bellow illustrates the superimposition of slow and fast decayingtransients on a 60Hz waveform.
Waveform with Slow / Fast Transients and Harmonics
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Interharmonics and Probabilistic Methods
Considering that interharmonics are naturally time-varying harmonic
components, due to its non-integer nature which causes the waveform to
change with time, a proper probabilistic treatment for its time-dependent
behavior is required. Figure below shows the time-varying nature ofinterharmonics.
0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.12
0
21.598
1.88
y t( )
0.10 t
Waveform with Harmonic and Interharmonics
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Standards: Setting Practical LimitsStandards: Setting Practical Limits
Recommendations for harmonic limits go back to the 1960s with ERRecommendations for harmonic limits go back to the 1960s with ERG5/2G5/2(UK). Presently the primary harmonics standards are IEEE 519 an(UK). Presently the primary harmonics standards are IEEE 519 and IECd IEC6100061000--33--6.6.
The standards are widely used and the steady state limits have bThe standards are widely used and the steady state limits have beeneenaccepted without much difficulties.accepted without much difficulties.
The IEEE 519, however, is going through a very thorough revisionThe IEEE 519, however, is going through a very thorough revision whichwhich
may result in an increase of steady state values for low voltagemay result in an increase of steady state values for low voltage systems.systems.Also IEEE 519a is under revision and should propose some limitsAlso IEEE 519a is under revision and should propose some limits forforshortshort--term duration bursts of harmonics.term duration bursts of harmonics.
The impact on sensitive electronic loads needs to be further invThe impact on sensitive electronic loads needs to be further investigated asestigated asthe limits have been established primarily for limiting thermalthe limits have been established primarily for limiting thermal effects.effects.
Other cumulative effect aspects such as capacitor aging due to vOther cumulative effect aspects such as capacitor aging due to voltageoltagestress, and partial discharge are also taken into account.stress, and partial discharge are also taken into account.
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Other Aspects
Probabilistic indices for harmonic distortion, characterization of multipleelectronic loads, accuracy of commercial measuring instrumentation, which
indicated the need for careful considerations when dealing with voltage
fluctuation and time-varying harmonic distortion.
Also the possible utilization of fuzzy logic in diagnostic system proceduresand time-varying flexible limits are considered (see Figure below with
IEEE 95% THD limits, maximum THD, and short-duration bursts).
5 10 15 20 25 300
5
10
15
20
Volta
geTHD
20
0
THD519 i
THD_Max i
THDTime_Varying i
301 i
Flexible THD Limits versus Time
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Integrating ToolsIntegrating Tools
Visualizationtech
niques
Frequ
ency d
omain
meth
ods
T im e d o m a in m e th o d s
Fourier
analysis
Spectra
lanalysis
Wavelet
analysi
s
Inte
lligen
t / pa
ttern
recogn
ition t
echn
iques
Fuzz
y log
ic ba
sed ana
lysis
S -transfor
mP r
obabilistic
analysis
E volutionaryspec
tra
T im e-frequ
ency analysis
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Real Time SimulationReal Time Simulation
Hardware In The LoopHardware In The Loop
Real Time Digital Simulator
Universalcontroller
D/A
A/D Protection relay
M
AC/AC power converter
(Motor Drive)
External Hardware
System Data in Simulation
Hardware response
MG
G
G
Controller
Relay
DC Load
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Real Time Simulation for Time-Varying Harmonics
Due to the complexity of time-varying harmonic distortion the most effective
way understand the physical phenomena is to analyze it in real time. A
time-varying harmonic distortion assessment based on real-time (RT)
hardware-in-theloop (HIL) test-bed modeling and simulation has beenproposed See Figure bellow. The sensitivity for power quality deviations
of a computer power supplies and variable speed drive controller cards have
been tested in the platform.
Star t
Selec t ing
Tes ted sys tem s
S elec ting P Q
p h e n o m e n a
E n d
U niversal in ter face
(e .g . , po w er am pl if iers ,
and transducers )
Fir ing bo ard
Refe rence
vol tages
P rint res ul ts
T es t sys tem 2
T es t sys tem 1
T es t sys tem N
Sel f des igned
V ol tage sag
THD
Frequency change
Fir ingpu lses
D igita l s im ulator
Diagram of universal real time simulation
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Wavelets for Distortion Analysis and Measurements
Difficulties with the use the FFT-algorithm for time-varying distortionconditions o require new approaches. A wavelet transform maps the time-
domain signals in a real-valued time-frequency domain and overcomes the
FFT shortcomings. The use of wavelets for power quality analysis has been
broadly applied. The topic is explored in great detail by many researchersand recently related to measurement techniques to overcome FFT
limitations. Figure (a, b and c) below for an example of the application of
wavelets to continuously rising distorted current). In (b) and (c) we see the
real and reactive power coefficients associated with the current waveform(a).
(a)
(a)
Current Waveform (a) Real (b) and Reactive (b) Powers Coefficients Using Wavelets
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Case1
Wavelets Multi-Resolution Analysis with Signal,
Approximation and Detail Coefficients (1%)
Signal
Approximation
Coefficient
Detail Coefficients
5th Harmoni
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Case1
Wavelets Color Map
Transient (1%)5th Harmonic (1%)
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FFTCase1
0 50 100 150 200 250 300 350 400 450 5000
0.2
0.4
0.6
0.8
1
1.2
1.4
Frequency(Hz)
Abs.
Magn
itude
5th
Harmonic
5th harmonic detectable - Transient lost
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Case 2
Wavelets Multi-Resolution Analysis with Signal,
Approximation and Detail Coefficients (0.5%)
Signal
ApproximationCoefficient
Detail Coefficients
5th Harmoni
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Case 2
Wavelets Color Map
Transient (0.5%) 5th Harmonic (0.5%)
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Case 3
Wavelets Multi-Resolution Analysis with Signal,
Approximation and Detail Coefficients (0.1%)
Signal
ApproximationCoefficient
Detail Coefficients
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Case 3
Wavelets Color Map
Transient (0.1%) 5th Harmonic (0.1%)
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300 Hz time-varying sinusoidal and 420Hz stationary sinusoidal waveform
S Transform Modified Wavelet Color Map Coefficients
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Transients (1000Hz)
S Transform Modified Wavelet Color Map Coefficients
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Wavelets can determine the presence ofWavelets can determine the presence oftransients and harmonic distortions of very smalltransients and harmonic distortions of very smallvalues: up to less than 0.5%.values: up to less than 0.5%.
With values around 0.1% the detail coefficientsWith values around 0.1% the detail coefficientscan hardly detect the transient and harmonics.can hardly detect the transient and harmonics.
The color map seems more helpful in identifyingThe color map seems more helpful in identifying
both transients and harmonics as the magnitudeboth transients and harmonics as the magnitudeof the transients and harmonics values goof the transients and harmonics values gobellow 0.5%.bellow 0.5%.
These indicates the potential of wavelets toThese indicates the potential of wavelets toidentify signals (particularly transients and timeidentify signals (particularly transients and time--varying distortions) much more efficiently thanvarying distortions) much more efficiently thanFFT or any other signal processing technique.FFT or any other signal processing technique.
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( )Estimatei t
1( )i t
( )Load
i t
3( )i t
5 ( )i t
7( )i t
( )ni t
( )y t
1
Power Electronics and Controls
The adaptive algorithm identifies the amplitudes and the angles of the fundamental
and harmonic currents at a node. The identification results are used to generate the
reference signal for the filter. The harmonic selective feature of the filter lies in its
ability to eliminate specific harmonics, thereby improving power quality. In order to
achieve this objective, a reference signal is generated by using the combination ofdifferent estimation results of different harmonics or by one dominant harmonic.
MultiMulti Agents:Agents:
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MultiMulti--Agents:Agents:PQ MonitoringPQ Monitoring
Reconfiguration ExampleReconfiguration ExampleP Q A
I D A P Q A
P Q A
P Q AP Q A
P Q A
P Q A
P Q AP Q A
P Q AP Q A
P Q A
P Q A P Q A
P Q A
Intelligent Distribution Agent (IDA) and Power Quality Agent (PQA).
The locations of these agents are decided based on the availability of the measured
data and the components for which power quality needs to be monitored (e.g.,
sensitive loads, pulsed power loads, and generators).
The PQA reads the measured raw data from the electrical system, filters it, computespower quality indexes, and transmits the processed data to the IDA
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MultiMulti--Agents:Agents: PQ MonitoringPQ Monitoring
Reconfiguration ExampleReconfiguration Example Transmissionlevel
Distribution
levelIDA
PQAPQA
PQAPQA
IDA
PQA PQA
PQAPQA
IDA
PQA PQA
PQAPQA
IDA
PQA PQA
PQAPQA
IDA
PQA PQA
PQAPQA
IDA
PQA PQA
PQAPQA
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Case Studies on Flexible PQ ThresholdsCase Studies on Flexible PQ Thresholds
Purpose:Purpose: Establish proof of concept for introducing flexibleEstablish proof of concept for introducing flexible
thresholdsthresholds
Assumption:Assumption: Sensitivity studies have been conducted and VSensitivity studies have been conducted and VTHDTHD of Typeof Type
I has been relaxed toI has been relaxed to 9%9% ((exampleexample))
Metrics toMetrics to study effect of relaxed thresholdstudy effect of relaxed threshold Additional temperature rise due to harmonics andAdditional temperature rise due to harmonics and
associated life expectancyassociated life expectancy
Metrics quantified for 3 casesMetrics quantified for 3 cases
1)1) No additional current harmonic injections on DCNo additional current harmonic injections on DC--ZEDSZEDS
2)2) Current harmonic injections corresponding to relaxed VCurrent harmonic injections corresponding to relaxed VTHDTHD
3)3) TimeTime--varying current harmonic injections and loadvarying current harmonic injections and load
corresponding to maximum design criterioncorresponding to maximum design criterion
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Case study 1Case study 1
0.16280.1628 CCAdditional rise in tempAdditional rise in temp
1.21 %1.21 %VVTHDTHD (Phase C)(Phase C)
0 %0 %||77||
98.39 %98.39 %Life expectancyLife expectancy
0 %0 %||55||0.128680.12868 RR
System conditionsSystem conditions
No additional current harmonic injections
l
p
ph
hk V
V
h
= 121
l
p
phH
hkih V
V
hKT
= = 121
)(
1
2 22 TTT
T
K
E
ett +
=
Harmonic factor Additional rise in temperature (%)Life expectancy
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Case study 2Case study 2
2.152.15 CCAdditional rise in tempAdditional rise in temp
80.78 %80.78 %Life expectancyLife expectancy
8.35 %8.35 %VVTHDTHD (Phase C)(Phase C)
7.5 %7.5 %||77||9 %9 %||55||
0.128680.12868 RR
System conditionsSystem conditions
Current harmonic injections corresponding to
relaxed VTHD (9%)
Case study 3ase s u y
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Case study 3ase s u y
MaxMaxMinMinSystem parameterSystem parameter
21 sec21 sec15 sec15 sectt
3 %3 %
3 %3 %0.123820.12382
7.5 %7.5 %||77||
9 %9 %||55||0.128680.12868 R
R
Time varying current harmonic injections
1.50761.5076 CCAdditional riseAdditional rise
in tempin temp
6.31 %6.31 %VVTHDTHD (Phase C)(Phase C)
86.11 %86.11 %Life expectancyLife expectancy
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Fuzzy Logic in Power SystemsFuzzy Logic in Power Systems
Relatively few implemented applicationsRelatively few implemented applications
These are mainly focused on controllers andThese are mainly focused on controllers andsystem stabilizerssystem stabilizers
Prediction, Optimization and Diagnosis arePrediction, Optimization and Diagnosis are
growing areasgrowing areas
Fuzzy logic is great for diagnosing failureFuzzy logic is great for diagnosing failure
modes since there are rarely singlemodes since there are rarely single
measurements that definitively indicatemeasurements that definitively indicate
impending failureimpending failure
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Possible
Problems
Caution Severe
Distortions
Dangerous
Levels
Normal
Levels
3 4 5 6 7 8 9 THDv in %0
1
No
rmal
Below
Normal
Over
Heating
Very
Hot
Below
Nor
mal
90
100
110
120
150
Equ ip
men
tH
eatin
g
Tem p
er a
tur e
(Celsiu
s) Harmonic Distortion (THDv)Versus Equipment Heating
Color Code Harmonic Criteria
No Problem
Caution
Possible Problems
Imminent Problems
A New Approach
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Basic Diagnostic ModelBasic Diagnostic Model
Designed using MATLAB, Simulink andDesigned using MATLAB, Simulink and
Fuzzy logic toolboxFuzzy logic toolbox System has two inputs; harmonic voltageSystem has two inputs; harmonic voltage
and temperatureand temperature
Fuzzy Controller processes inputs andFuzzy Controller processes inputs and
outputs a degree of dangeroutputs a degree of danger
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Basic System with InputsBasic System with Inputs
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Fuzzy ControllerFuzzy Controller
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Membership RulesMembership Rules
Membership Rule Map
If Harmonic Voltage is medium and
the temperature is below_normalthen no problem
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Expanded SystemExpanded System
Considers variation in fundamentalConsiders variation in fundamental
voltage, third, fifth, and seventhvoltage, third, fifth, and seventhharmonics, total harmonic distortion, andharmonics, total harmonic distortion, and
temperaturetemperature
These ranges are derived from IEEE 519These ranges are derived from IEEE 519--
19921992 Recommended Practices andRecommended Practices and
Requirements for Harmonic Control inRequirements for Harmonic Control inElectric Power SystemsElectric Power Systems
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Input VariationsInput Variations
Input Variations
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Expanded Simulink ModelExpanded Simulink Model
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Expanded Simulink ModelExpanded Simulink Model
Similar to basic modelSimilar to basic model
Has three different fuzzy logic controlHas three different fuzzy logic controlstructuresstructures
Each input is analyzed with temperatureEach input is analyzed with temperature
to determine degree of dangerto determine degree of danger
Outputs are divided into four bins: noOutputs are divided into four bins: no
problem, caution, possible problems, andproblem, caution, possible problems, andimminent problemsimminent problems
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Simulation ResultsSimulation Results
Simulation is run forSimulation is run for24 hour period with24 hour period withnew inputs every 2new inputs every 2minutesminutes
Output can beOutput can beanalyzed for eachanalyzed for eachcomponentcomponentindividually orindividually or
collectively by lookingcollectively by lookingat the THD (bottom)at the THD (bottom)
Statistical of the Fuzzy LogicStatistical of the Fuzzy Logic
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Statistical of the Fuzzy LogicStatistical of the Fuzzy Logic
Processing AnalysisProcessing Analysis System can be run with uniform orSystem can be run with uniform or
Gaussian distributions on the inputsGaussian distributions on the inputs
Uniform Input Gaussian Input
Statistical of the Fuzzy LogicStatistical of the Fuzzy Logic
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Statistical of the Fuzzy LogicStatistical of the Fuzzy Logic
Processing AnalysisProcessing Analysis
No Problem Caution Possible Problems Imminent Problems
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Inputs represent possible typical harmonic levelsInputs represent possible typical harmonic levels System would require more tuning before actualSystem would require more tuning before actual
implementation.implementation.
System will be soon implemented and testedSystem will be soon implemented and testedusing RTDS (real time digital simulator withusing RTDS (real time digital simulator withhardware in the loop ) at CAPS (Center forhardware in the loop ) at CAPS (Center forAdvanced Power Systems / Florida StateAdvanced Power Systems / Florida StateUniversity) as part of an ONR ESRDC Project.University) as part of an ONR ESRDC Project.
The system will be implemented in a multiThe system will be implemented in a multi--equipment scenario together with a loss of lifeequipment scenario together with a loss of life
predictor of equipment of motors andpredictor of equipment of motors andtransformers, etc. subjected to harmonictransformers, etc. subjected to harmonicdistortions.distortions.
Possible Laboratory Tests Using RTDS
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Possible Laboratory Tests Using RTDS
Power Supply Case
dc-to-dc
Converter ComputeLoad
Rectifier
Bridge
CsSmoothingCapacitor
HarmonicsDistorted
Current
Identify voltage harmonic distortion levels in terms of THD and
Waveforms which can cause performance degradation on PC switch-mode
power supply and other electronic loads. A computer monitor could beattached to the power supply.
0 0.02 0.042
0
22
2
f11t( )
0
0.040 t
AC Voltage Input
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Amplifier
Input Power
PC Power Supply
RTDS Controls
Data Acquisition, etc
Load
RTDS Test Implementation
(Simple Case)
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RTDS Test Implementation
Power Supply Failure
VTHD ~ 20%
Time-Varying
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Input
Voltage
Output
Voltage
Surge In Peak Vac
Surge Out Peak Vdc
Fundamentals of a PC Power Supply
500 Hz Wave Surge Test
Fundamentals of a PC Power SupplyCritical Components
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CCritical components and typical range of technology in usethat impact power supply application concerns
Application
Concerns
CCritical Components Types or Range of Values
Impact on Power
Source
Harmonics DC link capacitor 330 F ~ 1000 F
Boost converter with or without
Filtering EMI filters 20dB/dec @ fc = 9 kHz ~ 260 kHz
low pass or band pass filter
Critical Components
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RTDS Test Implementation
(Hardware in the Loop Case)
Amplifier
Input PowerMotor Controller
RTDS Controls
Data Acquisition, etc
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Challenges
Research and Development
DG and Renewables IntegrationCompatibility with Transmission Requirements and Load
Sensitivity
Levels of Penetration per Technology
Integration of Communications and Computer Control
Systems IssuesState Estimation for Contingency Analysis
Modeling and Simulation: Graph Visualization e SoftwareIntegration
Real Time Hardware in the Loop
Probabilistic Aspects and Novel Techniques
Technology Development
C
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Challenges
Education
Philosophy: Maintain Balance Between Strong
Fundamentals & New Technologies and Concepts
Power Electronics (Voltage Source Converters:
Statcom)Artificial Intelligence (Neuro Nets, Fuzzy Logic, etc.)
Signal Processing (Wavelets, Kalman, etc.)
Modeling Simulation (Load Flow Stability Harmonics - Transients)
Probability Methods
Approach: New Topics Via Research / Paper Projects
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In SummaryIn Summary
Power Quality has a dynamic, timePower Quality has a dynamic, time--varying naturevarying nature
which with the increased complexity and sensitivitywhich with the increased complexity and sensitivityof equipment needs to be properly understood andof equipment needs to be properly understood andaddressed. Traditional methods are not sufficient.addressed. Traditional methods are not sufficient.
Advanced techniques and technologies, includingAdvanced techniques and technologies, includingrealreal--time modeling / simulation, power electronicstime modeling / simulation, power electronicssolutions, signal processing and controls applicationssolutions, signal processing and controls applicationsare available to assist in these tasks.are available to assist in these tasks.
These developments have the potential to aid theThese developments have the potential to aid thepower systems engineer to design and operate thepower systems engineer to design and operate thesystem with superior performance over traditionalsystem with superior performance over traditional
methods used for studying power quality issuesmethods used for studying power quality issuesti l l d titi l l d ti i ditii diti