Merlin Gerin Circuit breaker application guide

1 Merlin GerinCircuit breakerapplication guideMMMMMMMMMMMMMMERLIN Gerin multi 9C60NC63400Va6000242342410kA IEC - OFFO - OFFO - OFFO - OFF681357 Merlin Gerin multi 9C60NC25230Va600024178O - OFF10 kA IEC Gerin multi 9C60NC63400Va6000242342410kA IEC - OFFO - OFFO - OFFO - 22 SE90105%IralarmImIrIn=250A250NP93083 OFFMERLIN Gerin compactNS250 NUi 750V. Uimp AIEC947-2 UTE VDE BS CEI UNE NEMAUe(V)Icu(kA)Ics=100% Icu160 22 SE90105%IralarmImIrIn=250 AOFFMERLIN Gerin compactNS250 NUi 750V. Uimp AIEC947-2 UTE VDE BS CEI UNE NEMAUe(V)Icu(kA)Ics=100% Icu160/250 ApushtotrippushtotripMERLINGERIN multi 9ID'clicC3240 mA n 0,030A230Va2056420564ID'clicbi 40 ABS EN 61009a30003N1L13L2I . ONMERLIN Gerin multi 9NG 125 LIn = 125A220/240V380/415V440V500 VUe(V)5025156 IEC (kA) 22 SE90105%IralarmImIrIn=250A250NP93083 OFFMERLIN Gerin compactNS250 NUi 750V. Uimp AIEC947-2 UTE VDE BS CEI UNE NEMAUe(V)Icu(kA)Ics=100% Icu160/250 ApushtotrippushtotripIc P>Ir>ImtestfaultSTR 53 UE607590105 %IrIImIrIotrtm(s)x Inx Irx Iox Inon I2t off(s) at IrtestRtrtmImIrIMERLIN Gerin compactNS400 HUi (V)220/240380/415440500/525660/690100706 54035 IEC 947-2 UTE VDE BS CEIUNE NEMAIcu(kA)cat BIcs = 100% IcuIcw 6kA / 0,25sIn = 22 SE90105%IralarmImIrIn=250 AOFFMERLIN Gerin compactNS250 NUi 750V.

2 Uimp AIEC947-2 UTE VDE BS CEI UNE NEMAUe(V)Icu(kA)Ics=100% Icu160/250 ApushtotrippushtotripResetresetApIgI nIsdI iIrMicrologic 70 Ics = 100% Icu220/44052569010010085 Icw85kA/1sNX 32 H 947-2 UTEVDEBSCEIUNEASNEMAEN 60947-250/60 HzUeIcu(V)(kA)01253push OFFpush ONO OFFdischarged1 ContentsDescriptionCircuit breakers and system designThe requirements for electrical power distributionSafety and availability of energyStructure of LV electrical power distributionFunctions and technologies of protection devicesStandard BS EN 60947-2 current limitationCascadingDiscriminationEarth leakage protection discriminationRange of Circuit breakersDiscrimination rulesLV discrimination studyEnhanced discrimination and cascadingSupplementary requirementsTransformer informationCable fault reduction400Hz operationDC informationResidual current device selectionCircuit breaker markingsLV switch disconnectorsTechnical dataCascading tablesDiscrimination tablesType 2 co-ordinationtables for motor protectionCo-ordination with Telemecanique busbarSection123 Page3557721000 kVA1000 AMM100 A400 A100 A160 A75 kW16 A20 kV/400 V1000 kVA1600 A1000 kVA19 kA45 kA60 kA23 kA70 kAmainswitchboardbuilding utilitieslighting, heating.

3 Distributionswitchboard -industrial/commercialnon-priorityfeeder spriority feedersdistributiondistributionenclosure distributionworkshop 13 Section 1 System requirementsCircuit breakers and system designSafety and availability of energyStructure of LV electrical power distributionFunctions and technologies of protection devicesStandard BS EN 60947-2 current limitationCascadingDiscriminationDiscrim ination rulesEarth leakage protection discriminationCoordination of protection devicesRange of Circuit breakersLV discrimination studyEnhanced discrimination and cascadingPage567101519212526283043464 GlossaryEDW:SCPD:IEC:BS:CT:CU:MSB:BBT:MV :Isc:Isc(D1):Usc:MCCB:BC:Icu(*):IcuD1(*) Ue:Ui:Uimp:In:Ith:Ithe:Iu:Icm:Icu:Ics:Ic w: x x Ir:Ii:Isd:ElectroDynamic WithstandShort Circuit protection deviceInternational Electrotechnical CommissionBritish StandardCurrent transformerscontrol UnitMain SwitchboardBusbar TrunkingMedium Voltage (1kV to 36kV)Short- Circuit currentShort- Circuit current at the point D1 is installedShort- Circuit voltageMoulded case Circuit -breakerBreaking CapacityUltimate Breaking CapacityUltimate Breaking Capacity of D1 Rated operational voltageRated insulation voltageRated impulse withstand voltageRated operational currentConventional free air thermal currentConventional enclosed thermal currentRated uninterrupted currentRated short- Circuit making capacityRated ultimate short- Circuit breaking capacityRated service breaking capacityRated short time withstand currentAdjustable overload setting currentConventional non-tripping currentConventional tripping currentInstantaneous tripping setting currentShort time tripping setting current5 The design of LV installations leads to basic protection devicesbeing fitted for three types of faults:c overloadsc short-circuitsc insulation of these protection devices must allow for.

4 C the statutory aspects, particularly relating to safety of people,c technical and economic chosen switchgear must:c withstand and eliminate faults at optimised cost with respect to the necessaryperformance,c limit the effect of a fault to the smallest part possible of the installation in order toensure continuity of of these objectives requires coordination of protection deviceperformance, necessary for:c managing safety and increasing durability of the installation by limiting stresses,c managing availability by eliminating the fault by means of the Circuit -breakerimmediately upstreamThe Circuit - breaker coordination means are:c cascadingc the insulation fault is specifically dealt with by earth fault protection devices,discrimination of the residual current devices (RCDs) must also be and availability of energyare the operator s of protection devicesensures these needs are met atoptimised and availability of energyThe requirements of electrical power distribution6 The various levels of an LV electrical installationEach of the three levels of the installation has specific availability and safety of LV electrical powerdistributionThe requirements of electrical power distributionSimplified diagram of a standard installation covering most of the cases observed in kVA1000 AMM100 A400 A100 A160 A75 kW16 A20 kV/400 V1000 kVA1600 A1000 kVA19 kA45 kA60 kA23 kA70 kAmainswitchboardbuilding utilitieslighting, heating, distributionswitchboard -industrial/commercialnon-priorityfeeder spriority feedersdistributiondistributionenclosure distributionworkshop 1 Level ALevel BLevel C7 Circuit - breaker functionsThis connection device is able to close and break a Circuit regardless of current up toits breaking functions to be performed are.

5 C close the Circuit ,c conduct current ,c open the Circuit and break the current ,c guarantee requirements concerning installation, cost optimisation, management ofavailability and safety generate technological choices concerning the A: the Main Switchboard (MSB)This unit is the key to the entire electrical power distribution: availability of supply isessential in this part of the Short- Circuit currents are high due to:v the proximity of the LV sources,v amply sized busbars for conveying high This is the area of the power Circuit -breakersFunctions and technologies of theprotection devicesOwn current compensationdiagramProtection devices and theircoordination must be suited tothe specific features of At the main switchboard, the needfor energy availability is greatest,c At the sub-distributionswitchboards, limitation of stressesin event of a fault is important,c At final distribution, user safety Main data of these Circuit -breakers:v of industrial type, meeting standard BSEN 60947-2,v with a high breaking capacity lcu from 40 to 150 kA,v with a nominal rating of 1000 to more than 5000 A,v category B:- with a high lcw from 40 kA to 100 kA 1 s- with a high electrodynamic withstand (EDW),v with a stored energy operating mechanism allowing source of supply is ensured by total discrimination:v upstream with the protection fuses of the HV/LV transformer (*),v downstream with all the feeders (time discrimination).

6 (*) The value of HV/LV discrimination lies above all in the fact that resumption of operation hasfewer constraints in LV (accessibility, padlocking). This offers considerable advantages forcontinuity of Circuit -breakers are designed for high currentelectrical distribution:v they are normally installed in the MSBs to protecthigh current incomers and feeders;v they must remain closed in event of short-circuits soas to let the downstream Circuit - breaker eliminate thefaults. Their operation is normally Withstand (EDW) and high thermalwithstand characterised by a short time withstandcurrent lcw are is designed to be as great as possible by an owncurrent compensation B: the subdistribution boardsThese boards belong to the intermediate part of the installation:c distribution is via conductors (BBT or cables) with optimised sizing,c sources are still relatively close: short- Circuit currents can reach 100 kA,c the need for continuity of supply is still very devices must consequently limit stresses and be perfectly coordinatedwith upstream and downstream LV is the area of the moulded case Circuit -breakersThese Circuit -breakers must open and break the current as quickly as possible.

7 Themain need is to avoid as far as possible stresses at cable and connection level andeven at load level. For this purpose, repulsion at contact level must be encouragedin order to eliminate the fault even as the current is possible diagramsare:c with a single repulsionloop,c with double repulsionc with an extractor, amagnetic core pushing orpulling the of a repulsion diagram Fm = magnetic forceThe repulsion effects can be enhanced by implementation of magnetic circuits:c with effects proportional to the current square (U-shaped attracting or expulsioncircuit),c with effects proportional to the current slope (di/dt) and thus particularly effectivefor high currents (lsc).Main data of the moulded case Circuit -breakers:c of industrial type, meeting standard BSEN 60947-2,c with a high breaking capacity (36 to 150 kA),c with a nominal rating from 100 A to 1600 A,c category B for high rating Circuit -breakers (> 630 A),c category A for lower rating Circuit -breakers (< 630 A),c with fast closing and opening and with three operating positions (ON/OFF/Tripped).

8 Continuity of supply is ensured by discrimination:c partial, possibly, to supply non-priority feeders,c total for downstream distribution requiring high energy requirements of electrical power distribution9 Level C: Final distributionThe protection devices are placed directly upstream of the loads: discrimination withthe higher level protection devices must be weak short- Circuit current (a few kA) characterises this This is the area of the Miniature Circuit -breakeriiFmiThese Circuit -breakers are designed to protect finalloads. The purpose is to limit stresses on cables,connections and technologies for the miniature Circuit -breakers,mainly used at this installation level, prevent suchstresses from miniature Circuit -breakers, limitation partly dependson the magnetic actuator. Once the mechanism hasbeen released, it will strike the moving contact makingit move at a high speed very early on. Arc voltage thusdevelops very quickly at a very early stage. For smallrating Circuit -breakers, specific pole impedancecontributes to miniature Circuit - breaker is ideal for domestic useand for the protection of auxiliaries; it then conforms tostandard BSEN the other hand, if it is designed for industrial use, itmust meet standard BSEN data of these Circuit -breakers:ccccc a breaking capacity to match needs ( Below 10 kA on average),ccccc a nominal rating of to 125 A according to the loads to be supplied,ccccc normally intended for domestic applications: conform to standard BSEN protection devices installed must provide:ccccc current limitation,ccccc operating convenience,ccccc absolute safety,as these devices are handled by non-specialist in dependability needs and technologies have led to a marked increase instandard requirements for industrial Circuit -breakers.

9 Conformity with standard IEC947-2, renamed IEC 60947-2 in 1997 and BSEN60 947-2 can be considered as anall-risk insurance for use of Circuit -breakers. This standard has been approved byall principlesStandard BSEN 60947-2 is part of a series of standards defining the specificationsfor LV electrical switchgear:c the general rules BSEN 60947-1, that group the definitions, specifications andtests common to all LV industrial switchgear,c the product standards BSEN 60947-2 to 7, that deal with specifications and testsspecific to the product BSEN 60947-2 applies to Circuit -breakers and their associated trip operating data depend on the trip units or relays that control theiropening in specific standard defines the main data of industrial Circuit -breakers:c their classification: utilisation category, suitability for isolation, the electrical setting data,c the information useful for operation,c the design measures,c coordination of protection standard also draws up series of conformity tests to be undergone by the Circuit -breakers.

10 These tests, which are very complete, are very close to real operatingconditions. Conformity of these tests with standard BSEN 60947-2 is verified byaccredited of main dataVoltageUerated operational voltagedataUirated insulation voltageUimprated impulse withstand voltageCurrentInrated operational currentdataIthconventional free air thermal currentItheconventional enclosed thermal currentIurated uninterrupted currentShort-circuitIcmrated short- Circuit making capacitydataIcurated ultimate short- Circuit breaking capacityIcsrated service breaking capacityIcwrated short time withstand currentTrip unitIradjustable overload setting current x Irconventional non-tripping x Ir conventional tripping currentIiinstantaneous tripping setting currentIsdshort time tripping setting currentCircuit- breaker categoryCategory BSEN 60947-2 defines two Circuit - breaker categories:c category A Circuit -breakers, for which no tripping delay is provided. This is normallythe case of moulded case Circuit -breakers can provide current category B Circuit -breakers, for which, in order to provide time discrimination,tripping can be delayed (up to 1 s) for all short-circuits of value less than the is normally the case of power or moulded case Circuit -breakers with highratings.