Ribeiro Power Quality

7/31/2019 Ribeiro Power Quality

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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)?



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What is Power Quality (Different Deviations)?



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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)?



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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)?



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Generation

Transmission

Performance Parameters

Planning

Operation

Economic Feasibility

Distribution

Power Quality (The Economics Perspective)?



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Accessibility

Security

Continuity

Reliability

Voltage (Power) Quality

Performance Parameters



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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



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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


(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



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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



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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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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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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


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


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



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




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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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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



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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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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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(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

Documents

Ribeiro Power Quality