Modeling and Verification of Ultra-Fast Electro-Mechanical Actuators for HVDC Breakers

147 Pages·2015·7.05 MB·English

Modeling and Verification of Ultra-Fast
Electro-Mechanical Actuators for HVDC Breakers
ARA BISSAL
PhD Thesis
Stockholm, Sweden 2015
Electromagnetic Engineering
TRITA-EE 2015:010 School of Electrical Engineering, KTH
ISSN 1653-5146 SE-100 44 Stockholm
ISBN 978-91-7595-480-6 SWEDEN
Akademisk avhandlingsommed tillståndav KunglTekniskahögskolanframlägges
till offentlig granskning för avläggande av teknologie doktorexamen onsdagen den
22 maj 2015 klockan 10.00 i F3, Kungl Tekniska högskolan, Lindstedtsvägen 26,
Stockholm.
© Ara Bissal, May 2015
Tryck: Universitetsservice US AB
iii
Abstract
Thecontinuouslyincreasingdemandforcleanrenewableenergyhasrekin-
dled interest in multi-terminal high voltage direct current (HVDC) grids.
Although such grids have several advantages and a great potential, their
materialization has been thwarted dueto the absence of HVDCbreakers. In
comparison with traditional alternating current (AC) breakers, they should
operate and interrupt fault currents in a time frame of a few milliseconds.
Theaimofthisthesisisfocusedonthedesignofultra-fastelectro-mechanical
actuator systems suitable for such HVDCbreakers.
Initially, holistic multi-physics and hybrid models with different levels
of complexity and computation time were developed to simulate the entire
switch. These models were validated by laboratory experiments. Following
a generalized analysis, in depth investigations involving simulations comple-
mented with experiments were carried out on two of the sub-components of
the switch: the ultra-fast actuator and the damper. The actuator efficiency,
final speed, peak current, and maximum force were explored for different
design data.
The results show that models with different levels of complexity should
be used to model the entire switch based on the magnitude of the impulsive
forces. Deformations in the form of bending or elongation may deteriorate
the efficiency of the actuator losing as much as 35 %. If that cannot be
avoided, then the developed first order hybrid model should be used since
it can simulate the behaviour of the mechanical switch with a very good
accuracy. Otherwise, a model comprising of an electric circuit coupled to an
electromagnetic FEM model with a simple mechanics model, is sufficient.
It has been shown that using a housing made of magnetic material such
as Permedyn, can boost the efficiency of an actuator by as much as 80 %.
In light of further optimizing the ultra-fast actuator, a robust optimization
algorithm was developed and parallelized. In total, 20520 FEM models were
computed successfully for a total simulation time of 7 weeks. One output
from this optimization was that a capacitance of 2mF, a charging voltage of
1100V,and40turnsyieldsthehighestefficiency(15%)ifthedesiredvelocity
is between 10m/s and 12m/s.
The performed studies on the passive magnetic damper showed that the
Halbacharrangementgivesadampingforcethatistwoandahalftimeslarger
than oppositely oriented axially magnetized magnets. Furthermore, the 2D
optimization model showed that a copper thickness of 1.5mm and an iron
tubethat is 2mm thick is the optimum damper configuration.
Keywords: Actuators,Armature,Capacitors,Circuitbreakers,Coils,Damp-
ing, Eddy currents, Elasticity, Electro-mechanical devices, Electromagnetic
forces, Finite element methods, HVDC transmission, Image motion analy-
sis, Magnetic domains, Magnetic flux, Magnetic forces, Magnetic materials,
Magnets, Thermal analysis.
Sammanfattning
En ständigt ökande efterfrågan på ren, förnybar energi har återuppväckt
intressetförhögspändlikström(HVDC)ielnätmedfleräntvåändstationer.
Trots att dessa nät har flera fördelar och en stor potential har förverk-
ligandet förhindrats på grund av frånvaron av HVDC-brytare. I jämförelse
medenbrytareavväxelström(AC)måsteenHVDC-brytarekunnabrytaen
felström inom loppet av ett fåtal millisekunder.
Syftetmeddennaavhandlingärinriktatpåutformningenavultrasnabba
elektromekaniskaaktuatorsystemsomlämparsigförsådanabrytare.Dessaär
baserade på så kallade Thomsonspolar vilka består av en platt spiralformad
lindning vilken är kopplad till en uppladdad kondensator som sedan laddas
ur genom spolen som därvid alstrar en kraftimpuls.
Initialtutveckladesmultifysik-ochhybridmodellermedolikakomplexitet
och erforderlig beräkningstid för att simulera dessa aktuatorsystem.
Dessavalideradessedanmedlaboratorieexperiment.Däreftergenomfördes
eningåendemodelleringsstudie avaktuatorsystemetsingåendekomponenter,
den ultrasnabba aktuatorn och magnetiska dämparen. Aktuatorn verknings-
grad, sluthastighet, toppström och maximala kraft utforskades bl a för olika
designdata.
Resultaten visar att modeller av olika grad av komplexitet bör använ-
das för att modellera hela aktuatorn beroende på storleken av den alstrade
kraftimpulsen. Deformationer i form av böjning eller töjning kan försämra
verkningsgraden så mycketsom 35 %.
Omdessaeffekterintekanundvikas,bördenfullständigahybridmodellen
användaseftersomdenkansimuleraaktuatornsbeteendemedenmycketgod
noggrannhet. Annars är en modell bestående av en elektrisk krets med en
enkelmekanikmodellkoppladtillenelektromagnetiskFEMmodelltillräcklig.
Utförda studier visar att användningav en aktuatorfixtur gjord av mag-
netisktmaterial, exempelPermedyn,kanökaverkningsgradenhosaktuatorn
med upptill 80 %.
Medsyfteattytterligareoptimeradenultrasnabbaaktuatornutvecklades
enrobustoptimeringsalgoritmföranvändningavparallellakärnor.Meddenna
genomfördes under7veckorstidtotalt 20520 FEM-beräkningar. Ettresultat
från denna optimering var att en kapacitans på 2mF, en laddningspänning
av 1100V och 40 lindningsvarv ger en högsta verkningsgrad (15%) om den
önskade sluthastigheten ligger mellan 10m/s och 12m/s.
Genomfördastudieravdenmagnetiskadämparenvisarbl.a.attomdean-
vändapermanentmagneternautförsiformavettHalbacharrangemangmedför
dettaendämpandekraftsomärtvåochenhalvgångerstörreänommotsatt
axiellt orienterad magnetiserade magneter används.
Acknowledgements
Firstly,Iwouldliketoexpressmygratitudetomysupervisor,Prof. GöranEngdahl,
for his guidance, innovative ideas, and numerous comments throughout this PhD
thesis. SpecialthanksgoestoProf. RajeevThottappillilforhiscontinuoussupport,
and to Dr. Nathaniel Taylor for being one of the reviewers of this thesis. I’d also
like to thank Prof. Anders Eriksson, for being my pillar in mechanics.
A lot of this thesis work was made possible thanks to the collaborative and
fruitful working atmosphere at ABB AB Corporate Research. Therefore, I would
like to thank Dr. Mikael Dahlgren and Magnus Backman for trusting in me and
giving me the opportunity to work with Dr. Thomas Eriksson, Dr. Ener Salinas,
and Dr. Lars Liljestrand. Their advice and guidance was very beneficial especially
when it came to answering a lot of my technical questions. I was fortunate to get
to meet people like Dr. David Schaeffer, Dr. Zichi Zhang, Stephan Halen, Lars
Jonsson, Ola Jeppsson, Dr. Elisabeth Lindell, and Dr. Roberto Alves at ABB AB
Corporate Research. In my opinion, a nice working environment strongly depends
on the people whom you work with.
During my PhDstudies, I alsohad the privilegeof workingatABB DE Corpo-
rateResearchin Ladenburg,Germany,for a mobility of six months. I learneda lot
fromthisexperienceandhadthechancetoworkwithmanycompetentprofessionals
with different backgrounds such as Dr. Octavian Craciun, Dr. Veronica Biagini,
Dr. Christian Simonidis, Dr. Jörg Gebhadrt. Also, I would like to thank Dr.
Markus Schneider, Wolfgang Waldi, Dr. Guenther Mechler, Dr. Gregor Stengel,
Dr. Alexander Horch, and Dr. Ulf Ahrend. Last but not least, I would like to
express my gratitude to Dr. Andreas Decker, Dr. Arne Wharburg, Dr. Kim
Listmann,Dr. JanSchlake,AndreasSchader,andDietmar PostwithwhomI have
had very interesting discussions on the train from Darmstadt to Ladenburg. In
general, the hospitality and kindness of all my newfound German colleagues knew
no limits.
I will always cherishmy time at KTH especially because of outstanding friends
such as Dr. Samer Sisha, Dr. Andreas Krings, Dr. Shuang Zhao, Dr. Respi-
cius Kiiza, David Fernando Ariza González, Cong-Toan Pham, and Dr. Antonios
Antonopoulos. A very special thanks goes to my friend and colleague Jesper
Magnusson,with whomI haveworkedthe mostwith throughoutmy PhD.I would
also like to thank Peter Lönn not only for his help in IT matters at KTH, but also
v
vi
for his jolly character.
IdeeplyappreciatehavinginvaluablefriendslikeRamiBouHadir,HaniDakhil,
Joseph Noufaily, Anthony Saliba, and Elie Karaa who have travelled all the way
from Lebanon to Sweden to support me for my PhD defense.
Iwouldalsoliketothankmysisterforhersweetness,love,andsupport. Special
thanksgoestomymotherforsacrificingherlife toraiseandsupportmeeverystep
of the way. I hope one day I can make you as proud of me as I am of you.
Lastbutcertainlynotleast,IwouldliketothankSilviaLohfinkforherextreme
kindness and never ending love. She was like a candle in the midst of darkness,
illuminating the countless winter nights I spent writing this PhD thesis.
Ara Bissal
Stockholm, May 2015

Contents
Contents viii
1 Introduction 1
1.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1.1 Why HVDC? . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1.2 Limitations of Multi-terminal HVDC Grids . . . . . . . . . . 2
1.1.3 HVDC Breakers . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 Objectives of the Thesis . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.3 Thesis Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4 Scientific Contributions . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.5 List of Publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2 The Mechanical Switch 9
2.1 Requirements of the Mechanical Switch . . . . . . . . . . . . . . . . 9
2.2 Switch Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.3 Modeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.3.1 Electromagnetic Modeling . . . . . . . . . . . . . . . . . . . . 13
2.3.2 Thermal Modeling . . . . . . . . . . . . . . . . . . . . . . . . 17
2.3.3 Mechanical Modeling . . . . . . . . . . . . . . . . . . . . . . . 18
2.4 Model Validations by Experiments . . . . . . . . . . . . . . . . . . . 22
2.5 Results and Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . 27
2.5.1 Models With Finer Segmentations . . . . . . . . . . . . . . . 32
3 The Ultra-Fast Actuator 35
3.1 State of the art . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
3.1.1 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
3.1.2 Modeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
3.2 Modeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
3.3 Experimental Validation . . . . . . . . . . . . . . . . . . . . . . . . . 38
3.3.1 The Experimental Setups . . . . . . . . . . . . . . . . . . . . 38
3.3.2 Results and Discussion . . . . . . . . . . . . . . . . . . . . . . 41
3.4 Sensitivity Analysis. . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
3.4.1 The Electrical Circuit . . . . . . . . . . . . . . . . . . . . . . 44
viii
CONTENTS ix
3.4.2 The Magnetic Circuit . . . . . . . . . . . . . . . . . . . . . . 51
3.4.3 The Shape of the Actuator . . . . . . . . . . . . . . . . . . . 59
3.5 Brute Force Optimization . . . . . . . . . . . . . . . . . . . . . . . . 72
3.5.1 Setup of the optimization model . . . . . . . . . . . . . . . . 74
3.5.2 Results and Discussion . . . . . . . . . . . . . . . . . . . . . . 75
4 The Composite Magnetic Damper 97
4.1 State of the Art . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
4.2 Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
4.3 Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
4.4 Modeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
4.4.1 Static modeling . . . . . . . . . . . . . . . . . . . . . . . . . . 99
4.4.2 Transient Modeling. . . . . . . . . . . . . . . . . . . . . . . . 99
4.5 Model and Concept Verification . . . . . . . . . . . . . . . . . . . . . 100
4.5.1 Small Scale Prototypes. . . . . . . . . . . . . . . . . . . . . . 100
4.5.2 Large Scale Prototype . . . . . . . . . . . . . . . . . . . . . . 103
4.6 Optimal Damper Design . . . . . . . . . . . . . . . . . . . . . . . . . 105
5 Conclusions and Future Work 111
5.1 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
5.2 Future Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
A Math Operators 113
B Symbols and Acronyms 115
Bibliography 119
List of Figures 128