User Manual

DIR 1000587R0002 (L3821)
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3.1.6.3 Circuit-breaker state
TheLSIG-MMunitsrecordthestateofthecircuitbreakerbymeansofspecicwiringonthecircuitbreaker.Whenpresenceofcurrentisdetermined
withthecircuit-breakerinthe“OPEN”position,astateerrorissignaledbyawarningmessagebeingdisplayed
(seepar.3.5)and“warning”LEDlightingup.
3.1.7 Measurement functions
Thecurrentmeasuring(ammeter)functionisavailable.
Thedisplayshowshistogramswiththreephaseandneutralcurrentsonthemainpage.Inaddition,thecurrentofthephaseunderthegreatest
loadisgiveninnumericalform.Whereapplicable,theearthfaultcurrentisdisplayedonaseparatepage.
Theammeterfunctionsbothinself-poweringmodeandwithauxiliaryvoltage.Inthelattercase,ammeterandbacklightingarealwayson.Tolerance
fortheammetermeasuringchain(currentsensorplusammeter)isdescribedinparagraph3.1.9.10.
TheLSIG-MMreleasesprovideacompletesetofmeasurements:
-Currents:threephases(L1,L2,L3),neutral(Ne),earthfault
-Maintenance:numberofoperations,percentageofcontactwear,openingdatastorage
3.1.8 Watchdog
TheLSIG-MMunitsprovidesomewatchdogfunctionswhichcanguaranteepropermanagementofrelaymalfunctions.Thesefunctionsareasfollows:
 WatchdogforpresenceofAuxiliarypowersupplywith“plug”icondisplayed”.
RatingPlugvalidity.
 WatchdogforproperconnectionofTripCoil(TC).Anyfaultsareindicatedbyaspecialalarmmessageand“alarm”LEDcomingon;ifthe
communicationmoduleisinstalled,thisactivatestheopeningcoilcommand(Y0)whichopenstheCBwhentripisenabled.
3.1.9 Description of protection functions
3.1.9.1 Protection “L”
“L”istheonlyprotectionthatcannotbedisabledbecauseitisforself-protectionagainstoverloadingoftherelay.Thetypesoftripcurvesthatcan
besetaredividedintotwogroupsaccordingtothestandardtheyreferto.
Standard trip curve according to IEC 60947-2
Onlyonetypeofcurvecanbeset(t=k/I
2
)asdenedbyIEC60947-2standard.
Protectiontriptime-inversetime-isgivenbytheexpression:
wherel
f
≤ 12lnand1swherel
f
>12ln whereI
f
isthefaultcurrentand I
1
theprotectionthreshold.
NB:Timeexpressedinseconds.
Standard trip curve according to IEC 60255-3
Thereare3typesofcurvesthatcanbeset,denedbyIEC60255-3standardasA,BandC.
Protectiontriptime-inversetime-isgivenbytheexpression:
NB:Timeexpressedinseconds.
aandkaretwoparameters,suggestedbythestandard,whichvaryaccordingtotypeofslopeselected(e.g.fortypeBslopea=1andk=13.5);
bisaparameterintroducedbyABtoincreasethenumberofcurveswiththesameslope.Thisparameterisautomaticallycalculatedbysetting
parametert1(requiredtriptime3xI1).
3.1.9.1.1 Thermal memory “L”
Thethermalmemoryfunctioncanbeenabledforcableprotection.Itisbasedonthe“τL”parameterdenedasthetriptimeofthecurve(t1)
selectedat1.25xI1.
Releasetriptimecertainlyis100%oftheoneselected,afteratimeintervalτLhaspassedsincelastoverloadorsincelasttrip.Otherwise,triptime
willbereduced,dependingonoverloadoccurredandtimeelapsed.
LSIG-MMisttedwithtwoinstrumentstomakeupthisthermalmemory.Therstinstrumentoperateswhenthereleaseispowered(italsorecords
overloadsthathavenotlastedlongenoughtotriptherelease),whilethesecondworksevenwhenthereleaseisnotpowered,reducinganytrip
timesincaseofanimmediatere-closing,andisenabledassoonastheCBistripped.
ItistheLSIG-MMreleasethatautomaticallydecideswhichofthetwotouse,accordingtothevarioussituations.
NB:Thethermalmemoryfunctioncanonlybesetifthetypeofcurveselectedisthestandardone(t=k/I
2
)(seepar.3.1.9.1).
3.1.9.2 Protection “S”
Thisprotectioncanbedisabled;itcanbeofthexedtime(t=k)orinversetime(t=k/i
2
)type.Inthelattercase,triptimeisgivenbytheexpression
3.1.9.2.1 Thermal memory “S”
Thethermalmemoryfunctioncanbeenabledforcableprotectionintheeventthatthecurvewithinversetimeisselected.Thisisbasedonthe
“tS”parameterdenedastriptimeofthecurve(t2)selectedat1.5xI2.Theothercharacteristicsarethesameasthoseforthermalmemory“L”
(seepar.3.1.9.1.1).
where
( )
b
I
k
t •
−
=
1
α
I
f
isthefaultcurrentandI
1
theprotectionthresholdsetbyuser.
1
I
I
I
f
=
whereI
f
isthefaultcurrentandI
2
theprotectionthreshold.
where
max
100 t
2
(I )
f
2
,t
2
/I
n