An efficient scalable time-frequency method for tracking energy usage of domestic appliances ...

183 Pages·2015·5.71 MB·English

An efficient scalable time-frequency method for tracking
energy usage of domestic appliances using a two-step
classification algorithm
Paula Meehan
BEng
ADissertationsubmittedinfulfilmentofthe
requirementsfortheawardof
DoctorofPhilosophy(PhD)
tothe
DublinCityUniversity
FacultyofEngineeringandComputing,SchoolofElectronicEngineering
Supervisors: Dr. StephenDaniels,Dr. ConorMcArdle
September8,2015
Declaration
I hereby certify that this material, which I now submit for assessment on the
programme of study leading to the award of a PhD is entirely my own work, and
that I have exercised reasonable care to ensure that the work is original, and does
not to the best of my knowledge breach any law of copyright, and has not been
taken from the work of others save and to the extent that such work has been cited
andacknowledgedwithinthetextofmywork.
Signed: (Candidate)
StudentID: 56412521
Date: September8,2015
Acknowledgements
IwouldliketothankallthepeopleinDublinCityUniversityandtheEnergyDe-
signLab,pastandpresent,whohelpedmealongmyPhDjourney. Thisworkwould
not have been possible without the financial support of the School of Engineering,
to whom I am grateful. I’d like to thank my supervisors, Dr. Stephen Daniels and
Dr. ConorMcArdle,fortheirsupportandguidance.
A special thanks to Shane and Jie, who made the Energy Lab a place I wanted
to work. I would especially like to thank all those friends who’ve spent time with
me and provided me with much needed chocolate (and wine!). Thanks to JP and
his special brand of motivation, to Jean, Kelly and Jackie for the nights out and to
RuaidhriandOisinwhowerealwaysreadyforacupofteaandachat.
ToScott,whoprobablyendeduplearningmoreaboutmyPhDthanheevercared
toknow,thankyouforputtingupwithme,cheeringmeupwhenthingsweretough
andbeingtheretolistentomydiscoveries.
To my family, particularly my parents Sheila and Paul, thank you for your love,
support,andunwavering(andmaybesometimesdeluded)beliefinme. Thereisno
doubt in my mind that this PhD would not have been possible without the support
frombothmyfamilyandfriends.
III
Contributions
List of peer reviewed contributions
• P. Meehan, C. McArdle and S. Daniels. An efficient scalable time-frequency
method for tracking energy usage of domestic appliances using a two-step
classificationalgorithm. Energies,7041-7066,2014,doi:10.3390/en7117041.
• P. Meehan, S. Phelan, C. McArdle and S. Daniels. Temporal and frequency
analysis of power signatures for common household appliances. Symposium
on ICT and Energy Efficiency and Workshop on Information Theory and
Security (CIICT 2012), pages2227,Stevenage,UK,July2012, doi:10.1049
/cp.2012.1856. InstitutionofEngineeringandTechnology.
• S.Phelan,P.Meehan,andS.Daniels. UsingAtmosphericPressureTendency
to Optimise Battery Charging in Off-Grid Hybrid Wind-Diesel Systems for
Telecoms. Energies,3052-3071,2013,doi:10.3390/en6063052.
• S. Phelan, P. Meehan, S. Krishnamurthy and S. Daniels. Smart energy man-
agementforoff-gridhybridsitesintelecoms. SymposiumonICTandEnergy
Efficiency and Workshop on Information Theory and Security (CIICT 2012),
pages 1521, Stevenage, UK, July 2012, doi:10.1049/cp.2012.1855. Institu-
tionofEngineeringandTechnology.
• J. Yang, S. Phelan, P. Meehan, and S. Daniels. A distributed real time sensor
networkforenhancingenergyefficiencythroughICT.SymposiumonICTand
EnergyEfficiencyandWorkshoponInformationTheoryandSecurity(CIICT
IV
2012), pages 814, Stevenage, UK, July 2012, doi:10.1049/cp.2012.1854. In-
stitutionofEngineeringandTechnology.
V
List of other contributions
• Paula Meehan and Stephen Daniels. Identification of Domestic Appliances
usingNILM.PresentationofworkatRINCEResearchDay,January2013.
• Paula Meehan and Stephen Daniels. Temporal and Frequency Analysis of
Power Signatures for Common Household Appliances. Presentation of work
atFacultyofDCUEngineeringResearchDay,August2012
• Paula Meehan and Stephen Daniels. Temporal and Frequency Analysis of
Power Signatures for Common Household Appliances. Poster presentation
at Symposium on ICT and Energy Efficiency and Workshop on Information
TheoryandSecurity(CIICT2012),July2012.
• Paula Meehan and Stephen Daniels. Monitoring Appliance Power Usage
from a Single Point of Measurement. Presentation of work at RINCE Re-
searchDay,January2012
• Paula Meehan and Stephen Daniels. Efficiency of Energy Systems. Poster
presentationatFacultyofDCUEngineeringResearchDay,May2011. (Best
posteraward).
VI
Contents
Acknowledgements III
Contributions IV
ListofFigures XII
ListofTables XVIII
Abstract XXI
1 Introduction 1
1.1 Researchobjectives . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2 Solutionandcontributions . . . . . . . . . . . . . . . . . . . . . . 5
1.3 Organisationofthesisdocument . . . . . . . . . . . . . . . . . . . 7
2 Literaturereviewofdomesticapplianceidentification 9
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2 Anoverviewofloadidentification . . . . . . . . . . . . . . . . . . 10
2.3 Applicationsofloadidentification . . . . . . . . . . . . . . . . . . 10
2.4 Loadidentificationsignalacquisitiontechniques . . . . . . . . . . . 13
VII
2.5 Appliancecharacterisationsignaturetypes . . . . . . . . . . . . . . 15
2.5.1 Steadystatesignatures . . . . . . . . . . . . . . . . . . . . 15
2.5.2 Transientsignatures . . . . . . . . . . . . . . . . . . . . . 22
2.5.3 Ambientsignatures . . . . . . . . . . . . . . . . . . . . . . 25
2.6 Applianceclassificationalgorithmsandperformancemetrics . . . . 27
2.6.1 Performancemetrics: accuracy . . . . . . . . . . . . . . . . 33
2.6.2 Performancemetrics: complexity . . . . . . . . . . . . . . 36
2.6.3 Performancemetrics: efficiency . . . . . . . . . . . . . . . 37
2.7 Summarytableofstateoftheart . . . . . . . . . . . . . . . . . . . 37
2.8 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
3 Measurementtoolsandtechniques 41
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
3.2 Measurementsensors . . . . . . . . . . . . . . . . . . . . . . . . . 42
3.2.1 Currentsensor . . . . . . . . . . . . . . . . . . . . . . . . 43
3.2.2 Voltagesensor . . . . . . . . . . . . . . . . . . . . . . . . 45
3.2.3 Temperaturesensor . . . . . . . . . . . . . . . . . . . . . . 46
3.3 Dataacquisitiondevice . . . . . . . . . . . . . . . . . . . . . . . . 46
3.4 Calibrationofthemeasurementsystem . . . . . . . . . . . . . . . . 47
3.5 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
4 Ananalysisoftheelectricalsystem 51
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
4.2 Voltagesource . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
4.3 Domesticappliancesaselectricalloads . . . . . . . . . . . . . . . . 56
4.3.1 Appliancesandoperationmodes . . . . . . . . . . . . . . . 56
VIII
4.3.2 Typicalappliancesfoundinahousehold . . . . . . . . . . . 61
4.3.3 Appliancetestset . . . . . . . . . . . . . . . . . . . . . . . 62
4.3.4 Appliancecurrentvariationduringoperation . . . . . . . . 70
4.4 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
5 IdentifyingappliancesusingsignaturesbasedonFFTharmonicsanda
naiveBayesclassifier 73
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
5.2 Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
5.3 Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
5.3.1 Signaturelibrary . . . . . . . . . . . . . . . . . . . . . . . 78
5.3.2 NaiveBayesclassifier . . . . . . . . . . . . . . . . . . . . 80
5.4 Experimentalprocedure . . . . . . . . . . . . . . . . . . . . . . . . 82
5.5 ResultsandAnalysis . . . . . . . . . . . . . . . . . . . . . . . . . 84
5.5.1 UsingthesteadystateFFTtoidentifyappliancesinisolation 85
5.5.2 Identifying appliance combinations and comparing using a
virtual signature library versus a real measured signature
library . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
5.6 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
6 Atwostepclassificationmethodthatusesatimefrequencysignature 92
6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
6.2 Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
6.3 Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
6.3.1 Event detection and the extraction of the FFT signature of
anevent . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
IX
6.3.2 Signaturelibrary . . . . . . . . . . . . . . . . . . . . . . . 102
6.3.3 StepI:classifyloadTYPEusingthetransientsignal . . . . 104
6.3.4 Step II: classifying appliance using steady state signal and
naiveBayesclassifier . . . . . . . . . . . . . . . . . . . . . 107
6.4 Experimentalprocedure . . . . . . . . . . . . . . . . . . . . . . . . 108
6.5 ResultsandAnalysis . . . . . . . . . . . . . . . . . . . . . . . . . 111
6.5.1 Accuracyofeventdetection . . . . . . . . . . . . . . . . . 111
6.5.2 AccuracyofTYPEclassification . . . . . . . . . . . . . . . 112
6.5.3 Differences between TYPE I and II appliance steady state
signatureswithrespecttovoltage . . . . . . . . . . . . . . 114
6.5.4 Accuracyofapplianceidentification . . . . . . . . . . . . . 115
6.5.4.1 Effectofbackgroundappliances . . . . . . . . . 118
6.5.4.2 Effectofnumberofharmonicsinsignature . . . . 119
6.5.5 ApplyingTYPEclassificationatOFFevents . . . . . . . . 120
6.6 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
7 Conclusion 125
7.1 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
7.2 Contributionsofthiswork . . . . . . . . . . . . . . . . . . . . . . 128
7.3 FutureWork . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
8 Appendices 133
8.1 Measurementboxschematic . . . . . . . . . . . . . . . . . . . . . 133
8.2 Voltageandharmonicsmeasuredindifferentenvironments . . . . . 136
8.3 Applianceharmonicdistributions . . . . . . . . . . . . . . . . . . . 141
8.4 Transientsignalprofileandrateofchangeplotsforallappliances . . 142
X