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1 INTRODUCTION
The European Union aims to be climate neutral by
2050, an objective included in the European Green
DealandinlinewiththeEUʹscommitmenttoaction
global measures to combat climate change, taken
together with the Paris Agreement. Power from
offshorerenewablesourceswould playa
keyrolein
achievingthisgoal.Accordingtotheestimatesofthe
European Commission, electricity will represent at
least50%ofthetotalenergymixin2050,and30%of
futureelectricitydemandwillbeprovidedbyoffshore
windenergy.
“TheEuropeanCommissionestimatesthat240‐450
GW of offshore
wind power is needed by 2050 to
achieve this goal [1]. She is determined to drive
developmentoffshorewindandexploreits potential
intheseasandalongthecoastsofEurope,respecting,
at the same time, the ecological limits of natural
resourcesandtheinterestsofothersmaritimeusers”
[2,
3]. There are currently 110 offshore wind farms
(OWF) in operation with over 5,000 wind turbines.
Negativeeffectscouldoccurthroughoutthelifecycle
of an offshore wind turbine, on during the
construction,operation and decommissioningstages.
Lubricationofwindturbinesisveryimportantduring
their operation. The purpose of
this paper is to
presentadescriptionoffunctionalityofthecondition
monitoring system and of the influence of metal
particlesinoilsystem[4].
2 MATERIALSANDMETHODS
The wind turbine has automatic lubrication on
subsystems:blades, hub,gearbox, brake, etc. (Figure
1)[5].
Considerations Regarding Oiling System for Offshore
Wind Turbines
M.Panaitescu,F.V.Panaitescu,G.P.Panait&A.A.Scupi
ConstantaMaritimeUniversity,Constanta,Romania
ABSTRACT:Powerfromrenewablesourceswouldplayakeyroleinthefutureofelectricity.Thewindenergy
isoneofthegoalofEUʹscommitment,whichwanttodevelopoffshorewindpotential[1],[2].Lubricationof
wind turbines is very important for maintenance [3]
. The purpose of this paper is to present some
considerations about monitoring oiling system. This system monitors kinematic data in real time. The
importanceofmonitoringrealdatawiththissystemhelpustosimulatelubricationforvarioustypesofwind
turbinereducersinordertochoosetheoptimal
formofthelubricationsystemandforgoodmaintenance.
http://www.transnav.eu
the International Journal
on Marine Navigation
and Safety of Sea Transportation
Volume 17
Number 3
September 2023
DOI:10.12716/1001.17.03.0
7
564
Figure1.Windturbinecircuitsoflubrication.
Lubricationsystemsguaranteemachinedurability
andeliminatedowntime.
2.1 Thelubricationofwindturbineblades
In automatic operation, the bearing lubrication is
continuouslyoperatedatanintervalat6hours(canbe
parameterised). In this connection, the grease pump
and the 3/2 directional solenoid control valve are
simultaneously actuated by the
plant control via a
coupling relay. The power supply ensues via an
automatic circuit breaker of the turbine electric
(Figure2)[3].
The duration of the lubricating interval must be
determined in tests at various temperatures. It not
exceed20minutes. The pump buildsup pressure in
the lines which causes
all the distributors to be
supplied with grease. The plant control switches of
the grease pump and of the 3/2 directional solenoid
control valve at the same time. The distributors
delivertheirlubricanttothebearingandthepressure
switchisreset.
Figure2.Lubricationpumpcircuit[3]
Ifexternalfaultsoccurduringautomaticoperation,
lubricationishaltedandcontinuedagainatthepoint
where it was interrupted after the fault has been
eliminated.
2.2 Themonitoringoilysystem
Thissystemmonitorskinematicdataandreceivesreal
dataforpowerfrommaincontrollerofwindturbine
(Figure3)[6].
Figure3.Oilingautomaticmonitoringsystem[6]
Also, the sensor of this system detects metallic
particles in the oiling system (Figure 4) [6]. When
detect any vibration pattern deviation, respond by
sendingansignalalarmthroughthenetworksystem,
whichis connectedwiththewind turbine’stop box.
This box transmitted output to control unit of
monitoring system
and after to an external personal
computer.AllrealdataaremonitoringwithSCADA
system.Theimportanceofmonitoringrealdatawith
this system consists in: configuration of the system
withdivetrainkinematic data,fibberopticcablefor
all communications between top box, monitoring
systemandnacelle,softwaretools
fordataanalysis.
1‐filter assembly; 2‐lubrication pump; 3‐ metal particle
sensor;4‐suctionhose;5‐motor.
Figure4.Lubricationsystemwithmetalparticlesensor[6]
2.3 Thesimulationoflubricationonwindturbinegearbox
The recent technology suggests using a pinion to
automatically lubricate open gears. This type of
monitoringrealdataisusefultosimulatelubrication
forvarioustypesofwindturbinereducersinorderto
choosetheoptimalformofthelubricationsystemand
forgoodmaintenance.
There are several types of gearboxes, the gears
varying in number between 4...7 as well as in size
(Figure5)[7].
565
Figure5.Thestructure,forcesandmotionsofwindturbine
gearbox.
“The statistical analysis and the graphical
presentation of the results of oil analyses are very
helpfultoolswhenassessingthetechnicalconditionof
machines.Basedontheprecisedataobtainedfromthe
analyses, the operators are able to maximize the
productionpotentialofthemachineparkandplanin
advance any
required service activities. Regular
lubricantmonitoringisanexcellenttoolthatprovides
a rich information on the technical condition of
machines“[9,10,11,12,13].
For simulation in 2 D the influence of metal
particle in oiling system of wind turbine, was
proposed a gearbox with two toothed wheels
(Table
1)(Figure6):
Table 1. The wind turbines normally gearbox data.
GearboxDiameter[mm] Numberofteeth
withtwotoothedwheels
1wheel12020
2wheel36060
Figure6.Gearingofthewheelsinthewindturbinegearbox.
The presence of oil in the gearbox is shown in
figure7:
Figure7.Theoilinsideofgearbox.
The oil occupies 75% of the casing volume. The
discretization network – Mesh consists of 49000
elements(Figure8):
Figure8.Thediscretizationnetwork.
Boundary conditions‐boundary limits are the
following:
TheEulerianmodelusedwith3phases(Figure9):
Phase1liquidoilwithadensityof890kg/m
3
;
Phase 2 solid – sawdust – scrapings, with a
density of 8000 kg/m
3
, occupies 2% of the oil
volume;
Phase 3 gaseous air with a density of 1.22
kg/m
3
.
Figure9.Distributionofthe3phasesinthegearbox.
Allobtainedresultssupportinterpretation.
566
3 RESULTSANDINTERPRETATIONS
Theresultsobtainedare:
Staticpressuredistribution‐increaseswithdepth
(asexpected,Figure10);
Figure10.Staticpressuredistribution.
The presence of metal in the lubricating oil is
visualized by the filings, which are uniformly
distributedin the oil. The wheels donʹt turn. The
sawdust is gravitationally pulled down (Figure
11);
Figure11.Themetalstreamlinesintheoil.
Inphase2,thestreamlinesshowushowthefiling
slides gently towards the base of the gearbox
(Figure11,Figure12);
Figure12.Thedistributionofsawdusttowardsthebaseof
thegearbox.
Theinterpretationsoftheseresultsare:
Apartofthepleatisdrawnintotheupperlayer,at
thecontactsurfaceoftheoilwiththeair,duetothe
surface tension, but its speed is very low, the
maximumvaluereaching0.00005m/s;
Itwasthenimposedthat
thegearsrotatelikethis:
thelargeronewith20rpminthetrigonometric
sense,
thesmallonewith60rpmclockwise.
Themaximumspeedisreachedontheoutsideof
thegearteethandhasavalueof0.438m/s.
Whenthegearsgetoutof
mesh,suctionisapplied
andthefilingsaredrawntotheteeth(Figure13);
Figure13.Thedistributionoffilings‐gearsgetoutofmesh
When the gears get in mesh, the compression is
done[12]andthefilingispushedoutoftheteeth
ofgear(Figure14);
Figure14.Thedistributionoffilings‐gearsgetinmesh.
The streamlines take the form of gear wheels
(Figure15);
Figure15.Phase2‐Velocitystreamlines.
After a few seconds of rotation, the following
aspectsappear:
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Theturbulenceincreasesalotaroundthegears[9,
10],a phenomenon visualized by thedistribution
of the velocity vectors (Figure 16, Figure 17) and
thecurrentlines(Figure18).
Figure16.Phase2‐Velocityvectorsdistribution.
Figure17.Phase2‐Velositydistributionafterfewseconds.
Figure18.Phase2.Streamlinesdistribution.
Finally,canobserved:
themaximumvalueofspeedwhenthegearsgetin
meshis4.388.10
‐1
m/s;
themaximumvalueofthe streamlines velocityis
4.272.10
‐1
m/s;
when the turbulence increases a lot around the
gears, the maximum value of velocity vectors is
4.388.10
‐1
m/s.
4 CONCLUSIONS
Thissystemwhichisusedformonitoringinrealtime
a metal particles is useful because sent a signal to
every 145 seconds to the monitoring device when a
particleisdetected.Whenappearafault,afaultsignal
is sent to the controller of automatic control
oiling
system.Thesechangesinthe operationalparameters
ofthewindturbineareinfluencedbyclimatechanges,
changes in temperatures, pressures, loads generated
bychangesinwindspeeds.Thecostsofrepairingor
reconditioningsomesystems,generatedbythelackof
continuous or defective monitoring of the wind
turbinesʹoperation,are
veryhigh,especiallythecosts
for gearboxes. The greater the wind force, the most
vulnerable the gears are. In this case, the offshore
wind turbines are the most susceptible to damage.
Thegearwheelteethmusthaveappropriatebending
strengthaswellasstrength.Thedangerous moment
appearwhenthe
teethcontacteachotherinthearea
of the pitch circles where no slip occurs, then mean
theoilfilmismissing.
ACKNOWLEDGMENT
Authors gratefully acknowledge to this material support
path received under Project BLOW2023‐2028‐ Black Sea
FLoatingOffshoreWind,GrantAgreementNº:101084323.
REFERENCES
[1]PeshcoV., Mendel B., MullerS.,MarkonesN.,Mercker
M., et.al., “ Effects of offshore windfarms of seabird
abundance:Strong effects in spring and in the breeting
season”,Marineenvironmentalresearch,2020
[2]https://www.europarl.europa.eu/meetdocs/2014_2019/pl
mrep/COMMITTEES/PECH/DT/2021/03‐
17/1217673RO.pdf
[3]https://gewindenergy.com,**GEDocumentationsWind
TurbinesSystems,2009.
[4]Panaitescu F.V., Panaitescu M., Juganaru
D.E.,”
Monitoring and data acquisition for a consumption
system based on renewable energies”, Int. Journal of
ModernManufacturingtechnologies,Vol.XIV,no.3,pp
184‐190,DOI10.54684,2022.
[5]https://lubemec.grouphes.com/wind‐power‐lubrication‐
maintenance,**”Automaticlubricationsolutions”,2023.
[6]https://gewindenergy.com,**GEDocumentationsWind
TurbinesGeneratorSystemsGE2.5xl,50Hz,
2009.
[7]https://www.lubetechnologies.com/wind.html, “ Wind
powqer generation‐Lubrication systems for wind
turbines”,2023.
[8] J. Ukonsaari, N.Bennstedt, “ Wind Turbines gear box”,
EnergiforskJournal,47,2016.
[9]Krzysztof Płonka, ” Lubricating oil analysis in wind
turbines gearboxes – part 1”, available on
https://www.ecol.com.pl/en/lubricating‐oil‐analysis‐in‐
wind‐turbines‐
gearboxes‐part‐1/.
[10]Bejger,A.,Frank,E.,Bartoszko,P.,“Failureanalysisof
windturbineplanetarygear”,EnergiesJournal,14,6768,
http://doi.org/10.3390/en14206768,2021.
[11]LatiffiantiE.,ShengS.,DingY.,“Windturbinegearbox
failure detection through cumulative sum of
multivariate time series data “, Energy Journal, vol.10,
https://doi.org/10.3389/fenrg.2022.904622,2022.
[12]
Park, C., Huang, J. Z., and Ding, Y. “ A Computable
Plug‐InEstimatorofMinimumVolumeSetsforNovelty
Detection.Operations Res.58, 1469–1480.
doi:10.1287/opre.1100.0825,2010.
[13] Pang, B., Tian, T., and Tang, G.‐J. “ Fault State
Recognition of Wind Turbine Gearbox Based on
Generalized Multi‐Scale Dynamic
Time
Warping”,Struct. Health Monit.20,3007–3023.
doi:10.1177/1475921720978622,2021.
