Voltage Control in the Future Power Transmission Systems

253 Pages·2018·10.526 MB·English

by  Nan Qin (auth.)

Springer Theses
Recognizing Outstanding Ph.D. Research
Nan Qin

Voltage Control in
the Future Power
Transmission Systems
Springer Theses
Recognizing Outstanding Ph.D. Research
Aims and Scope
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theses from around the world and across the physical sciences. Nominated and
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includeanextendedintroduction,aswellasaforewordbythestudent’ssupervisor
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and for other scientists seeking detailed background information on special
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contributions made by today’s younger generation of scientists.
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(cid:129) They must be written in good English.
(cid:129) ThetopicshouldfallwithintheconfinesofChemistry,Physics,EarthSciences,
Engineeringandrelatedinterdisciplinary fields such asMaterials,Nanoscience,
Chemical Engineering, Complex Systems and Biophysics.
(cid:129) The work reported in the thesis must represent a significant scientific advance.
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cance of its content.
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Nan Qin
Voltage Control in the Future
Power Transmission Systems
Doctoral Thesis accepted by
Aalborg University, Aalborg, Denmark
123
Author Supervisors
Dr. Nan Qin Prof. ClausLethBak
Department ofEnergy Technology Department ofEnergy Technology
Aalborg University Aalborg University
Aalborg Aalborg
Denmark Denmark
and Prof. ZhenChen
Department ofEnergy Technology
GridPlanning Aalborg University
Energinet Aalborg
Fredericia Denmark
Denmark
Hans Abildgaard
GridPlanning
Energinet
Fredericia
Denmark
ISSN 2190-5053 ISSN 2190-5061 (electronic)
SpringerTheses
ISBN978-3-319-69885-4 ISBN978-3-319-69886-1 (eBook)
https://doi.org/10.1007/978-3-319-69886-1
LibraryofCongressControlNumber:2017957835
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See how easy it is, once you know how?
To my wife, Si Chen
and my sons, Bohan Qin and Rubin Qin
’
Supervisor s Foreword
ItisagreatpleasuretointroduceDr.NanQin’sPh.D.thesisworkforpublicationin
theSpringeroutstandingthesesseries.Thebackgroundoriginallystemsfrommore
than 20 years of very fruitful cooperation between Danish Transmission System
Operator (TSO) Energinet and me. Before my employment as a university pro-
fessor, I worked in Energinet as a practicing engineer. This experience from the
earlyyearsaswellasanever-ongoingcooperationbothinresearchandeducations
within the area of Electric Power Systems has led to many really valuable results
over the years as well as a number of graduated B.Sc.’s, M.Sc.’s and Ph.D.’s of
which many today work in Energinet or other Danish power companies.
NanhadbeenemployedinEnerginetforsomeyearsbeforehestarteddiscussing
the possibility of taking an industrial Ph.D. as part of his work in Energinet. His
senior leader and later Ph.D. supervisor, Chief Engineer Hans Abildgaard (we
studiedtogetherandIhavebeencooperatingwithHansformanyyears)foundthat
it was a good idea and contacted me with an initial idea of the topic of such a
preliminary Ph.D. study plan.
This leads to an application at the Danish Innovationsfonden who can grant
supportforso-calledindustrialPh.D.’s.AnindustrialPh.D.isinitsmeritsequalto
a normal Ph.D., but is conducted in a very strong cooperation with an industry
participant, in this case Energinet. This assures that the research work is strongly
connected to the upfront research needs of the company. During the 3-year pro-
gress,thisisensuredbythecandidatebeingphysicallyinthecompanyforaperiod
equivalent to half of the study as well as conducting regular project meetings with
both academic supervisors and company supervisor and the team behind the pro-
ject.Thisleadstoresearchresultswhicharedirectlyapplicableinthedevelopment
ofthemeritsofthecompany.Asasupervisor,thisisaverysatisfyingprocesstobe
part of as the fruits of your own work together with the talented Ph.D. student
directly can be seen valuable and used in real life.
Nan Qin is a talented researcher. His topic requires an enormous overview of
boththepreviousworkconducted,practicesindifferentcountries,knowledgeofthe
ix
x Supervisor’sForeword
basicpowersystemtheories,aswellasanintodeepmathematicalinsightwhichcan
beconvertedintocomplicatedmathematicalprogramminginordertoshedlighton
the very complex behavior of an electric power transmission system. It has been
formulated a number of times that the electric power system is among the largest
and most complicated man-made machines. This is really visible and clear when
readingNan’swork.Thisisnotjustastand-alonesingularstudywith anumberof
easily identifiable variables but a highly complex and branch of study involving
power system optimization and future trends of operation of the power system.
Nan’s study is entitled “Voltage control in the future power transmission sys-
tem”.Thedesignandoperationofthetransmissionsystemofthefutureisgenerally
averychallengingtaskasthehugeinclusionofrenewablessuchassolarandwind
powerchallengestheoriginallayoutandoperationofthepowersystemasdesigned
decades ago with a structure different than the needs prescribed nowadays.
EspeciallyDenmark,whoareamongthetoprunnersintheworldofreplacingfossil
fuels with renewable sources, faces major challenges as the shutdown of conven-
tional generation being replaced by noncontrollable offshore wind power plants
leads to a very different set of operational conditions to maintain safe operation
of the power system. Furthermore, the partial replacement of the transmission
systemwithundergroundcablesposesahugechangeinthereactivepowerbalance
and pushes the need to using shunt reactors for compensation.
Nan’s work consists of an automatic voltage control decision-making process
formulatedintoaMORPF(Multi-stageoptimimalreactivepowerflow)framework
which is solved using nonlinear programming. His methods are implemented in a
model of the west-Danish power system and demonstrated using several realistic
casestudiesbaseduponrecordedoperationaldataandstatisticallybasedprognoses
of wind power production. The case studies show that the proposed method is
superiorwithregardtokeepingvoltageincontrolaswellasminimizingtheoverall
cost due to losses and switching actions.
ThisisacknowledgedbyEnerginetandNanistodayamongimplementingparts
ofhisworkinthenewSCADAsysteminEnerginet.Itisagreatpleasuretobethe
supervisor of such a piece of research work which can be seen having immediate
influence in the design of the control system of the future.
NanreceivedthefollowingfinalcommentsinhisassessmentofhisPh.D.thesis:
“With this research, we find that Nan Qin has delivered a practical and useful
engineeringcontributioninthefieldsrelatedtocoordinatedvoltagecontrolandloss
minimizationintransmissionnetworkswithalargepenetrationofwindpower.The
dissertationreportsasolidandadvancedengineeringworkbasedonstate-of-the-art
scientific methods.”
Besides this, Nan is a very nice person to work with. He is always very open
and attentive toward discussions and advises, and he possesses an enormous
work capacity. The extent of his work surely exceeds the usual expectations for a
Ph.D. thesis. Nanhadhis struggles andchallenges duringthemostcritical partsof
hisprogress,buthemanagedtogetherwithhissupervisorsalwaystoovercomethe
Supervisor’sForeword xi
mostdifficultandchallengingpartsofhisworkwhichhaveledtotheresultspresent
in your hand.
I sincerely hope you enjoy reading Nan’s thesis and that the results provided
may become useful.
Aalborg, Denmark Prof. Claus Leth Bak
June 2017