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UniGear type ZS1Medium voltage, arc-proof, air-insulated,metal-clad switchgear
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UniGear type ZS1
UniGear 550
Double Level UniGear
Double Busbar System UniGear
UniGear type ZVC
Marine Applications
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1UniGear type ZS1
Page Chap.
Description 4 1.1
Air-insulated 6 1.2
Loss of sevice continuity 8 1.3
Safe 10 1.4
Type-tested 12 1.5
Arc-proof 14 1.6
Vacuum circuit-breaker 16 1.7
Gas circuit-breaker 20 1.8
Vacuum contactor 22 1.9
Service trucks 24 1.10
Switch-disconnector 26 1.11
Instrument transformers 28 1.12
Measurement sensors 30 1.13
Distribution and automation 32 1.14
Automatic transfer systems 40 1.15
Typical units and technical data 42 1.16
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UniGear
The Refinementin MV Switchge
Characteristics• Metal-clad, air-insulated switch-
gear.• Suitable for medium voltage
distribution.• Guaranteed arc-proof units.• Factory-tested for indoor installa-
tions.• Tested in accordance with the
main international Standards.• Wide range of functional units
available for all installationsolutions.
• Compartments segregated bymetallic partitions.
• Modular structure, easily built-up.• Highly effective use of space.• Extremely compact contactor unit
with fuses.• Fitted with double-level units.• Start-up, maintenance and
service operations can be carriedout from the front.
• Apparatus handling with the doorclosed.
• Units can be installed against thewall.
• Limited and simple maintenanceactivities.
• Complete with mechanical safetyinterlocks.
• Earthing switch with full makingcapacity.
• Studied to guarantee maximumservice continuity.
• Complete apparatus range: gasand vacuum circuit-breakers, con-tactors and switch-disconnectors.
• Conventional or integratedprotection and measurementsystems.
• Fitted with conventionalinstrument transformers or newgeneration sensors.
Description
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1.1
ear
Applications
Utilities and Power Plants• Power generation stations• Transformer stations• Switching stations• Main and auxiliary switchgear.
Industry• Pulp and Paper• Cement• Textiles• Chemicals• Food• Automotive• Petrochemical• Quarrying• Oil and gas pipelines• Metallurgy• Rolling mills• Mines.
Marine applications• Rigs• Drilling platforms• Off-shore oil rigs• Tender ships• Passenger ships• Container ships• Tankers• Cable ships• Ferries.
Transport• Airports• Ports• Railways• Underground transport.
Services• Supermarkets• Shopping malls• Hospitals• Large infrastructures and civil
works.
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Air-insulated
The switchgear is modular and is built up byplacing standardised units side by side in acoordinated way. The switchgear is simple toconfigure and selection of the apparatus andinstruments does not imply dedicated solutions.The functional units of the switchgear areguaranteed arc proof in accordance with the IEC62271-200 Standards, appendix AA, class Aaccessibility, criteria 1 to 5. All the start-up,maintenance and service operations can becarried out from the front. The switchgear and theearthing switches are operated from the front withthe door closed. The switchgear can be wall-mounted. The range of apparatus for UniGearswitchgear is the most complete available on themarket, being able to count on vacuum and gascircuit-breakers and vacuum contactors with fuses.All this apparatus is interchangeable inside thesame switchgear unit. This makes use of a singleswitchgear-user interface possible, with the sameservice and maintenance procedure andoperations. The fixed version switch-disconnectorunits complete the range of apparatus. Theswitchgear can be fitted with conventional(transformers and releases) or innovative (sensorsand multi-purpose unit) measurement andprotection components.Apart from the traditional functional units, theUniGear switchgear is fitted with double-levelsolutions, compact units equipped with contactorswith fuses and double busbar systems. The use ofthese units allows extremely efficient use of space.
StandardsThe switchboard and main apparatus contained init comply with the following Standards:• IEC 60694 for general purposes.• IEC 62271-200 for the switchgear.• IEC 62271-102 for the earthing switch.• IEC 60071-2 for the insulation coordination.• IEC 62271-100 for the circuit-breakers.• IEC 60470 for the contactor.• IEC 60265-1 for the switch-disconnector.
Normal service conditionsThe rated characteristics of the switchboard areguaranteed under the following ambient conditions:• Minimum ambient temperature: – 5 °C• Maximum ambient temperature: + 40 °C• Maximum relative humidity: 95%• Maximum altitude: 1000 m a.s.l.• Presence of normal, non-corrosive and uncon-
taminated atmosphere.
As a leading company in research, developmentand innovation, ABB is able to provide the mostcomplete and suitable solutions for satisfyingpresent needs and future requirements ofproducers, distributors and users of electric power.The medium voltage switchgear is one of the mostimportant links in the electric distribution chainand ABB has developed the UniGear switchgearwith the aim of satisfying all requirements.UniGear is a combination of consolidatedsolutions and innovative components, both ofwhich are fruit of ABB technology.UniGear is medium voltage metal-clad switchgearwith a metal enclosure, suitable for indoorinstallations.Metal partitions segregate the compartments fromeach other and the live parts are air-insulated.
From generating stations down to installationdistribution substations, ABB provides the mostreliable and top quality solution for supplyingproducts, systems and services.As sole partner, ABB is the largest and mostcomplete supplier in the world of switchgear andsystems for electric power transmission anddistribution. ABB substations, cables,transformers, control systems and switchgear areused by our customers for efficient use of electricpower.
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1.2
Degrees of protectionThe degrees of protection of theswitchboards conform with IEC60529 Standards.UniGear switchboards are normallysupplied with the following standarddegrees of protection:• IP4X on the external housing.• IP2X inside the units.On request, the external housing canbe supplied with different degrees ofprotection up to a maximum of IP53.The electrical characteristics of theswitchboard can vary for ambientconditions other than those de-scribed and for higher degrees ofprotection than the standard ones.
Colour of the external surfacesRAL7035.
Electrical characteristics
Rated voltage
Rated insulation voltage
Rated power frequency withstand voltage
Rated lightning impulse withstand voltage
Rated frequency
Rated short-time withstand current
Peak current
Internal arc withstand current
Main busbar rated current
Branch connection rated current
Branch connection rated current
with forced ventilation
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24
50
125
50-60
…25
…63
…25
–
…2500
630
1250
1600
2000
2300
–
2500
–
17.5
17.5
38
95
50-60
…40
…100
…40
–
…4000
630
1250
1600
2000
2500
3150
3600
4000
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12
28
75
50-60
…50
…125
…40
…50
…4000
630
1250
1600
2000
2500
3150
3600
4000
7.2
7.2
20
60
50-60
…50
…125
…40
…50
…4000
630
1250
1600
2000
2500
3150
3600
4000
kV
kV
kV 1min
kV
Hz
kA 3s
kA
kA 1s
kA 0.5s
A
A
A
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Loss of service continuity
Compartments
Each unit consists of three power compartments:apparatus [A], busbars [B] and feeder [C].There are two versions available for closing theapparatus and feeder compartment doors - withscrews or central handle.Each unit is fitted with an auxiliary compartment[D], where all the instruments and cabling arehoused.Arc-proof switchgear is normally provided with aduct [E] for evacuation of the gases produced byan arc.All the units are accessible from the front and themaintenance and service operations can thereforealso be carried out with the switchgear wallmounted.The compartments are segregated from eachother by metallic partitions.
Main busbars
The busbar compartment contains the mainbusbar system connected to the fixed upperisolating contacts of the apparatus by means ofbranch connections.The main busbars are made of electrolytic copper.Up to 2500 A, the system is made with flat bus-bars; for currents between 3150 A and 4000 A, aspecial copper section is used.The busbars are normally covered with insulatingmaterial. There is a single busbar compartmentalong the whole length of the switchgear and thiscan be fitted with segregations for dividing eachunit into compartments.
Branch connections
The feeder compartment contains the branchsystem for connection of the power cables to thefixed lower isolating contacts of the apparatus.The branch connections are made of electrolyticcopper. They are made with flat busbars for thewhole range of currents and are normally coveredwith insulating material.
Earthing switch
Each incoming/outgoing feeder compartment canbe fitted with an earthing switch for cable earthing.The same device can also be used to earth thebusbar system (measurements and bus-tie units).It can also be installed directly on the main busbarsystem in a dedicated compartment (busbarapplications).The earthing switch has short-circuit makingcapacity.
With IEC 62271-200, new aspects relative to newdefinitions and classifications of MV switchgearhave been introduced. One of the most significantchanges introduced in this release is thatclassification of switchgear into metal-clad,compartmented and cubicle types has beencompletely abandoned. Revision of switchgearclassification rules has been based on the user’spoint of view, in particular on aspects like serviceand maintenance of the switchgear, according tothe requirements and expectations for goodsubstation management, from installation todismantling. In this context, Loss of ServiceContinuity has been chosen as a fundamentalparameter for the user.
According to the updated rules, UniGearswitchgear can be defined as follows:
1. Interlock-controlled accessible compartmentcompartment containing high-voltage parts,intended to be opened for normal operation and/ornormal maintenance, in which access is controlledby integral design of the switchgear andcontrolgear.
2. Procedure based accessible compartmentcompartment containing high-voltage parts,intended to be opened for normal operation and/ornormal maintenance, in which access is controlledby a suitable procedure combined with locking.
3. LSC2BBusbar, feeder and apparatus compartmentsphysically and electrically segregated.This is the category that defines the possibility ofkeeping other compartments and/or functionalunits energised when opening a main circuitcompartment.
4. Partition ClassMetal-enclosed switchgear and controlgearproviding continuous metallic partitions and/orshutters (if applicable), intended to be earthed,between opened accessible compartments andlive parts of the main circuit.Metallic partitions and shutters or metallic parts ofthem shall be connected to the earthing point ofthe functional unit.
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1.3
A
C
D
E
B
Control of the apparatus is from the front of theswitchgear with either manual or motor-operatedoperation.The position of the earthing switch can be seenfrom the front of the switchgear by means of anindicator.
Earthing busbarThe earthing busbar is made of electrolytic copper.It runs longitudinally all round of the switchgear,thereby guaranteeing maximum personnel andinstallation safety.
Insulating bushings and shuttersThe insulating bushings contained in the appara-tus compartment contain the fixed contacts forconnection of the apparatus with the busbarcompartment and feeder compartment respective-ly. They are single-pole type and are made ofepoxy resin. The shutters are metallic and areactivated automatically during movement of theapparatus from the racked-out position to theservice position and vice versa.
CablesSingle and three-core cables up to a maximum oftwelve per phase can be used depending on therated voltage, the unit dimensions and the cablecross section.The switchgear can be wall-mounted in the stationbecause the cables are easily accessible from thefront.
Gas exhaust ductThe gas exhaust duct is positioned above theswitchgear and runs along its whole length.Each power compartment is fitted with a flappositioned on the top of it. The pressure generatedby the fault makes it open, allowing the gas topass into the duct.Evacuation from the room of the hot gases andincandescent particles produced by the internalarc must normally be carried out. The UniGearswitchgear is fitted with a complete range ofsolutions to deal with all requirements, either inthe case where evacuation is possible directly atthe end of the switchgear, or when solutions fromthe front or rear are requested.Some installations, such as marine ones, do notallow conveyance of the gases to the outside ofthe room and therefore dedicated solutions havebeen realised to guarantee personnel safety and
conformity with the Standards, such as expansionchambers, absorbent filters and longitudinalevacuation chimneys.
Busbar applicationsEach switchgear unit can be fitted with an acces-sory busbar application:• current or voltage transformers for busbar
measurements• busbar system earthing switch• top entry duct to make interconnections be-
tween different pieces of switchgear.
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Safe
The UniGear switchgear is fitted with all theinterlocks and accessories needed to guaranteethe high level of safety and reliability both for theinstallation and operators.
InterlocksThe safety interlocks can either be the standardones [1-2-3] or those available on request [4-5].The former are foreseen by the Standards and aretherefore necessary to guarantee the correctoperation sequence. The latter can be supplied onrequest and they must be foreseen by the installa-tion service and maintenance procedures.Their presence guarantees the highest level ofreliability even in the case of an accidental errorand allows what ABB defines as an “error-free”system of interlocks.
KeysThe use of key interlocks is very important inrealising the interlocking logics between units ofthe same switchgear, or of other medium, low andhigh voltage switchgear. The logics are realised bymeans of distributors or by ringing the keys.The apparatus truck [6] can be locked in theracked-out position and the relevant lock key canonly be removed with the apparatus in this posi-tion. The earthing switch closing [7] and opening[8] operations can be locked by means of keys.The latter can only be removed with the earthingswitch in an opposed position to the lock to bemade. These locks can also be applied to theearthing switch of busbar applications.The apparatus racking-in/out operations [9] andearthing switch opening/closing [10] can beprevented by means of key locks, which preventinsertion of the relevant operating levers. The keylock can also be applied to the earthing switch ofbusbar applications. The keys can always beremoved.
PadlocksThe apparatus [11] and feeder [12] compartmentdoors can be locked in the closed position bymeans of padlocks. These can be applied to bothdoor closing versions - with screws or centralhandle.
The operations for apparatus racking-in/out [13]and earthing switch opening/closing [14] can beprevented by applying the padlocks to the inser-tion slots of the relevant operating levers.The padlock can also be applied to the earthingswitch of busbar applications.The metallic segregation shutters [15] can belocked by means of two independent padlocks inboth the open and closed positions.The switchgear is preset for using padlocks with a4 to 8 mm diameter.
Locking magnetsThe locking magnets are used to make automaticinterlock logics without human intervention.The apparatus racking-in/out [16] and the earthingswitch opening/closing [17] operations can beprevented. This magnet can also be applied to theearthing switch of busbar applications.The doors of the apparatus [18] and feeder [19]compartments can be locked in the closed posi-tion. The magnets can be applied to both doorclosing versions - with screws or with centralhandle.The magnets operate with active logics andtherefore the lack of auxiliary voltage makes thelock become operative.
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1.4
Standard safety interlocks (mandatory)
Additional safety interlocks (on request)
Padlocks
Locking magnets
Lock Condition
4 A Apparatus compartment door opening Truck in service or undefined position
B Apparatus racking-in Apparatus compartment door open
5 A Feeder compartment door opening Earthing switch open
B Earthing switch opening Feeder compartment door open
Lock Condition
1 A Apparatus racking-in/out Apparatus closed
B Apparatus closing Undefined truck position
2 A Apparatus racking-in Apparatus multi-contact plug unplugged
B Apparatus multi-contact plug unplugging Truck in service or undefined position
3 A Earthing switch closing Truck in service or undefined position
B Apparatus racking-in Earthing switch closed
6 Apparatus racking-in lock Can only be removed with the truck in the racked-out position
7 Earthing switch closing lock Can only be removed with the earthing switch open
8 Earthing switch opening lock Can only be removed with the earthing closed
9 Insertion of the apparatus Can always be removedraking-in/out crank lever
10 Insertion of the earthing switch Can always be removedoperating lever
11 Apparatus compartment door opening
12 Feeder compartment door opening
13 Insertion of the apparatus raking-in/out crank lever
14 Insertion of the earthing switch operating lever
15 Shutters opening or closing
16 Apparatus racking-in/out
17 Earthing switch opening and closing
18 Apparatus compartment door opening
19 Feeder compartment door opening
Accessory devices
20 Shutters fail-safe The device locks the shutters in the closed position when the apparatus is removed fromthe compartment. The operator cannot open the shutters manually. The shutters can onlybe operated by the apparatus truck or the service trucks.
21 Apparatus-switchgear The apparatus multi-contact plug and relative switchgear unit socket are equipped unitunit compatibility matrix compatibility matrix with a mechanical matrix, that disables apparatus racking-in into a
switchgear unit with an inappropriate rated current.
22 Circuit-breaker mechanical The apparatus compartment is equipped with a mechanical device, that enables circuit-operating mechanism breaker closing and/or opening directly by means of the front operating mechanism
pushbuttons, keeping the door closed. The controls can be operated with the circuit-breakers in the service and racked-out position.
Keys
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Type-tested
Arc withstand test.
The UniGear switchgear has under-gone all the tests required by theinternational (IEC) Standards andlocal Standards (for example, theChinese GB and Russian GOSTstandards). Apart from this, the testsrequired by the main shippingregisters (LR, DNV, RINA, BV andGL) have been carried out for use ofthe switchgear in marine installa-tions.As indicated in the regulations ofthese standards, the tests werecarried out on the switchgear unitsconsidered most sensitive to theeffects of the tests and therefore theresults were extended to the wholerange.
The tests simulate situations which occur veryrarely or even never in the installations. Forexample, a short-circuit at the maximum currentlevel for which the installation has been designedis rather unrealistic because of the presence ofcurrent-limiting components (such as the cables)and because the power available is normally lowerthan the rated one.Apart from this, each switchgear unit is subjectedto the routine tests in the factory before its deliv-ery.These tests are aimed at a functional check of theswitchgear based on the specific characteristics ofeach installation.
Type tests:• Short-time and peak withstand current.• Temperature rise and main circuit impedance
measurements.• Dielectric test on main and auxiliary circuits.• Making and breaking capacity of the apparatus.• Earthing switch making capacity.• Mechanical operations.
Type tests required by the shipping regis-ters:• High ambient temperatures (45 °C).• Inclination.• Vibration.
Routine factory tests:• Visual inspection and check.• Mechanical sequence operations.• Cabling check.• Electrical sequence operations.• Insulation test.• Measurement of the resistance of the main
circuits.
Type tests:• Short-time and peak withstand currentThe test shows that the main power and theearthing circuits resist the stresses caused by thepassage of the short-circuit current without anydamage. It should also be noted that both theearthing system of the withdrawable apparatusand the earthing busbar of the switchgear aresubjected to the test. The mechanical and electri-cal properties of the main busbar system and ofthe top and bottom branch connections remainunchanged even in the case of a short-circuit.
• Temperature riseThe temperature rise test is carried out at therated current value of the switchgear unit andshows that the temperature does not becomeexcessive inside of it. During the test, both theswitchgear and the apparatus it may be fitted withare checked (circuit-breakers, contactors andswitch-disconnectors). Apparatus subject to testingin free air is able to withstand higher rated cur-rents than that inserted in a switchgear unit,therefore the rated current of the apparatusdepends on the characteristics of the switchgearand on the relevant ventilation system (natural orforced).
• DielectricThese tests check that the switchgear has suffi-cient capability to withstand the lightning impulseand the power frequency voltage. The powerfrequency withstand voltage test is carried out asa type test, but is also routine on every switchgearunit manufactured.
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1.5
Inclination test.
Vibration test.
• Apparatus making and breaking capacityAll the apparatus (circuit-breakers, contactors andswitch-disconnectors) are subjected to the ratedcurrent and short-circuit current breaking tests.Furthermore, they are also subjected to theopening and closing of capacitive and inductiveloads, capacitor banks and cable lines.
• Earthing switch making capacityThe earthing switch of the UniGear switchgear canbe closed under short-circuit. In actual fact, theearthing switch is normally interlocked to avoidbeing operated on circuits which are still live.However, should this happen for any one ofseveral reasons, safety of the personnel operatingthe installation would be fully safeguarded.
• Mechanical operationsThe mechanical life tests of all the operating partshighlight the reliability of the apparatus.General experience in the electro-technical sectorshows that mechanical faults are one of the mostcommon causes of a fault in an installation.The switchgear and apparatus it contains aretested by carrying out a high number of operations- higher than those which are normally carried outin installations in service. Moreover, the switchgearcomponents are part of a quality program systemand are regularly taken up from the productionlines and subjected to mechanical life tests toverify that the quality is identical to that of thecomponents subjected to the type tests.
Type tests required by the shipping regis-ters:
• High ambient temperaturesThe service conditions of the electrical apparatusin shipping installations are generally more severethan those in normal land applications.The temperature is certainly one of these factorsand for this reason the shipping register regula-tions require the switchgear to be able to operateat higher ambient temperatures (45 °C, but evenhigher) than those foreseen in the IEC Standards(40 °C).
The switchgear hasundergone the vibrationtest with a frequencyband from 2 to 100 Hzand with the followingmotion with:– 1 mm amplitude in
the frequency rangebetween 2 and 13.2Hz.
– 0.7 g accelerationamplitude in thefrequency rangebetween 13.2 and100 Hz.
• VibrationThe reliability and sturdiness of the UniGearswitchgear has been definitively proven by theresult of the withstand test to mechanical stressesdue to vibration. The service conditions on ship-ping installations and marine platforms require theswitchgear to work in environments stronglyaffected by vibrations, such as those caused bythe operating motors on board large cruise shipsor on the drilling plants of oil rigs.
• InclinationThe test is carried out by inclining the switchgear fora defined time up to 25° alternatively on all foursides and operating the apparatus (circuit-breaker,contactor and earthing switch).The test proves that the switchgear is able to resistthese extreme service conditions and that all theapparatus it contains can be operated without anyproblems and without being damaged.
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When developing modern medium voltage switch-gear, personnel safety must necessarily take firstplace and this is why the UniGear switchgear hasbeen designed and tested to withstand an internalarc due to a short-circuit current of the same levelas the maximum short-time withstand level.The tests show that the metal housing of UniGearswitchgear is able to protect personnel operatingnear the switchgear in the case of a fault whichevolves as far as striking an internal arc.An internal arc is among the most unlikely offaults, although it can theoretically be caused byvarious factors, such as:
• Insulation defects due to quality deterioration ofthe components. As an example, the causes canbe adverse environmental conditions and ahighly polluted atmosphere.
• Overvoltages of atmospheric origin or generatedby operation of a component.
• Incorrect operations due to not respecting theprocedures or to inadequate training of thepersonnel in charge of the installation.
• Breakage or tampering of the safety interlocks.• Overheating of the contact area, due to the
presence of corrosive agents or when theconnections are not sufficiently tightened.
• Entry of small animals in the switchgear.• Material left behind inside the switchgear during
maintenance operations.The characteristics of the UniGear switchgearnotably reduce the incidence of these causes ingeneration of faults, but some of them cannot beeliminated definitively.The energy produced by the internal arc causesthe following phenomena:• Increase in the internal pressure.• Increase in temperature.• Visual and acoustic effects.• Mechanical stresses on the switchgear struc-
ture.• Melting, decomposition and evaporation of
materials.Unless suitably controlled, these can have veryserious consequences for the operators, such aswounds (due to the shock wave, flying parts andthe doors opening) and burns (due to emission ofhot gases).
The test checks that the compartment doorsremain closed and that no components areejected from the switchgear even when subjectedto very high pressures, and that no flames orincandescent gases come out, thereby ensuringthe physical integrity of the personnel operatingnear the switchgear.Moreover that no holes are produced in theexternal freely accessible parts of the housing andfinally, that all the connections to the earthingcircuit remain efficacious, guaranteeing the safetyof personnel who may access to the switchgearafter the fault.The IEC 62271-200 Standard describes themethods to be used for carrying out the test andthe criteria which the switchgear must conform to.The UniGear switchgear fully conforms to all thecriteria indicated:1 The doors of the switchgear must remain
closed and no opening of the cover panels mustoccur.
2 Any part of the switchgear which may behazardous for personnel must not be ejected.
3 No holes must appear in the external housingof the switchgear in any parts accessible topersonnel.
4 The vertically and horizontally arranged fabricindicators placed outside the switchgear mustnot get burnt.
5 All the switchgear earthing connections mustremain effective.
In the case where classification IAC is proven bythe tests, the metal enclosed switchgear will bedesignated as follows:– General: classification IAC (initials for Internal
Arc Classified)– Accessibility: A, B or C (switchgear accessible to
authorized personnel only (A), to all (B), notaccessible due to installation (C))
– Test values: test current in kiloamperes (kA),and duration in seconds (s).
UniGear switchgear is classified IAC AFLR.When installing the switchgear, some fundamentalpoints must be taken into consideration:• Level of the fault current (16...50 kA).• Duration of the fault (0.1...1s).• Escape routes for the hot and toxic gases given
off by combustion of materials.• Dimensions of the room, with special attention
to the height.
Arc-proof
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1.6
The limiting systems are based on sensors whichexploit the pressure or light generated by the fault.The ITH and FRD devices (20 ms activation time)belong to the former family, whereas the TVOCand REA systems (3 ms activation time)belong to the latter.
ITHThe sensors consist of microswitches positionedon the top of the switchgear near the gas exhaustflaps of the three power compartments (apparatus,busbars and feeder). The shock wave makes theflats open and operate the microswitchesmconnected to shunt opening releases of the circuit-breakers.
FRDThis system consists of pressure sensors locatedin the auxiliary compartment and connected to thethree power compartments by means of smalltubes. The sensors detect the rising front of thepressure wave which develops on the outburst ofthe arc and react by making the circuit-breakersopen. The sensors are protected against theexternal environment and can be checked evenwith the switchgear in service.
TVOCThis system consists of an electronic monitoringdevice located in the auxiliary compartment whichthe optic sensors are subject to. These aredistributed in the various power compartments andare connected to the device by means of opticfibres. When a certain established light level isexceeded, the device opens the circuit-breakers.To prevent the system from interveningdue to light occasionally generated by externalphenomena (flash of a camera, reflections ofexternal lights, etc.), current transformers can alsobe connected. The protection module only sendsthe opening command to the circuit-breaker if itreceives the light and short-circuit current signalsimultaneously.
REAPlease refer to page 38.
The parameters of each specific plant mean thatevacuation of the hot gases and incandescentparticles must be checked very carefully in orderto ensure and maintain personnel safety.UniGear switchgear is fitted with a complete rangeof solutions to deal with all requirements, whenevacuation is possible inside the room, but alsowhen this is not compatible with the plant charac-teristics, as in the case of shipping installations.
UniGear switchgear offers complete passive typeprotection against the effects of a fault due to aninternal arc by means of its structure for a time of1s up to 40 kA and 0.5s at 50 kA.ABB has also developed protection systems whichallow very important objectives to be achieved:
• Detection and extinction of the fault, normally inless than 100ms.
• Limitation of the consequences of the fault onthe apparatus.
• Limitation of out of service.
For active protection against an internal arc,devices consisting of various types of sensors canbe installed in the various compartments, whichdetect the immediate outburst of the fault andcarry out selective opening of the circuit-breakers.
Steel
Copper
Cables
Arc duration anddamage caused
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VD4
Vacuum circuit-breaker
UniGear switchgear can be fitted with the widestrange of apparatus available on the market todayand of these the vacuum circuit-breaker nowoccupies a position of prime importance in allsectors of primary distribution.Vacuum circuit-breakers cover the whole range ofswitchgear parameters and therefore the wholerange of applications.Dozens of years of experience gained in develop-ing and using vacuum interrupters are todayreflected in the range of ABB circuit-breakers,which stand out for their exceptional electrical andmechanical characteristics, extremely longand low maintenance life, compactness and theuse of highly innovative construction techniques.ABB develops and produces a complete range ofinterrupters for use in circuit-breakers and contac-tors and for all medium voltage applications.
The VD4 medium voltage circuit-breaker interrupt-ers use the vacuum to extinguish the electric arcand as the insulating medium.Thanks to the unequalled properties of vacuumand the breaking technique used, current interrup-tion takes place without arc chopping and withoutovervoltages. Restoration of the dielectric proper-ties following interruption is extremely rapid.The VD4 circuit-breakers are used in electricaldistribution for control and protection of cables,overhead lines, transformer and distributionsubstations, motors, transformers, generators andcapacitor banks.
PolesThe VD4 medium voltage circuit-breakers usevacuum interrupters embedded in resin poles.Embedding the interrupter in the resin makes thecircuit-breaker poles particularly sturdy andprotects the interrupter itself against shocks,deposits of dust and humidity.The vacuum interrupter houses the contacts andmakes up the interruption chamber.ABB circuit-breakers use the most advancedvacuum breaking techniques: with radial magneticflow for circuit-breakers with medium-low perform-ances and with axial magnetic flow for those withhigh breaking capacity. Both techniques guaranteeeven distribution of the arc roots over the wholesurface of the contacts, allowing top performancesat all current values.The structure of a vacuum interrupter is relativelysimple. The housing is made up of a ceramicinsulator closed at the ends by stainless steelcovers.The contacts are made of pure copper andsintered chrome and are welded to the copperterminals. A metallic bellows allows movement ofthe moving contact-terminal group, at the sametime guaranteeing that the vacuum is maintainedin the interrupter.The interrupter components are welded in anenvironment under a very strong vacuum toguarantee a vacuum of less than 10-5 Pa in theinterrupter.The interrupter does not therefore contain anyionisable material. In any case, on detachment ofthe contacts, an electric arc is generated whichonly consists of the melted and vaporised materialof the contact.A metallic shield is integrated insidethe interrupter to capture the metallic vapoursgiven off during interruption, as well as for control-ling the electric field. The particular shape of thecontacts generates a magnetic field which forcesthe arc to rotate and to involve a much widesurface than that of a fixed contact arc. Apart fromlimiting the thermal stress on the contacts, all thismakes contact erosion negligible and, above all,allows the interruption process to be controlledeven with very high short-circuit currents. Theelectric arc remains supported by the externalenergy until the current passes through its naturalzero.The ABB vacuum interrupters are zero currentinterrupters and are free of any re-striking phe-nomena.
17
1.7
Apparatus-operator interfaceThe front part of the circuit-breaker represents theinterface of the apparatus with the user personnel.It is fitted with the following accessories:• Opening pushbutton.• Closing pushbutton.• Operation counter.• Indicator of the circuit-breaker open and closed
state.• Indicator of the charged or discharged state of
the operating mechanism springs.• Manual charging device of the operating mecha-
nism springs.• Override selector of the undervoltage release
(optional).
StandardsIEC 62271-100 for the circuit-breaker.
The rapid reduction of the current density and fastcondensation of the metallic vapours, simultane-ously with the instant of zero current, allow themaximum dielectric strength between the inter-rupter contacts to be re-established within a fewthousandths of a second. Supervision of thevacuum level is not necessary as the circuit-breaker poles are sealed-for-life pressure systemsand do not require any maintenance.
Operating mechanismThe VD4 circuit-breaker is fitted with a mechanicalstored energy type operating mechanism.Trip is free and therefore allows opening andclosing operations independent of the operator.The operating mechanism spring system can berecharged either manually or by means of ageared motor.The apparatus can be opened and closed bymeans of the pushbuttons on the front of theoperating mechanism or by means of electricreleases (shunt closing, shunt opening andundervoltage).The circuit-breakers are always fitted with an anti-pumping device to eliminate the possibility ofsimultaneous opening and closing commands,closing commands with springs discharged or withthe main contacts not yet in their run-end position.
TruckThe poles and operating mechanism are fixedonto a metal support and handling truck.The truck is provided with a wheel system whichmakes the operations for racking the apparatusinto and out of the switchgear unit possible withthe door closed. The truck allows efficient earthingof the circuit-breaker by means of the metallicstructure of the switchgear unit.The vacuum circuit-breaker truck can be motor-operated.The racking-out and racking-in operations can becarried out by means of electrical controls, eitherlocally by the operator or by a remote system.
18
Vmax
Vacuum circuit-breaker
Vmax medium voltage circuit-breakers are thesynthesis of ABB technology in designing andconstructing vacuum interrupters and of theexcellence of design, engineering and productionof the circuit-breakers. They find their idealuse in UniGear ZS1 type switchgear 550 mm wideup to 17.5 kV, 1250 A and 31.5 kA.Vmax circuit-breakers are used in electricaldistribution for control and protection of cables,overhead lines, transformer and distributionsubstations, motors, transformers, generators andcapacitor banks.
Insulating monoblocThe structure of Vmax is particularly innovativesince instead of have three distinct separate poles,it has a single insulating monobloc where thethree vacuum interrupters are housed. Themonobloc and operating mechanism, of themechanical type with a spring for operating energystorage, are fixed to a sturdy metallic frame. Thecompact structure ensures the same sturdinessand mechanical reliability as a traditional circuit-breaker consisting of an operatingmechanism/pole base cover and three separatepoles. The low speed of the contacts together withthe reduced run and the mass container, limit theenergy required for the operation and thereforeguarantee extremely limited wear on the system.This means the circuit-breaker requires limitedmaintenance.
The interrupters of the Vmax medium voltagecircuit-breakers are the same as those used in theVD4 and VM1 series. The Vmax series thereforeguarantees the same characteristics as thevacuum series mentioned above, i.e. interruptionof the currents without arc chopping and overvolt-ages and extremely rapid recovery of the dielectricproperties after the interruption.
Operating mechanismThe Vmax series is fitted with a mechanicaloperating mechanism of simple conception anduse, derived from the same mechanical operatingmechanism which equips the VD4 series.The stored energy operating mechanism with freetrip therefore allows opening and closing opera-tions independent of the operator. The springsystem of the operating mechanism can berecharged both manually and by means of ageared motor. Opening and closing of the appara-tus can take place both by means of the pushbut-tons located on the front of the operating mecha-nism, and by means of the electric releases (shuntclosing, shunt opening and undervoltage).The circuit-breaker is always fitted with a mechani-cal anti-pumping device to prevent repeatedsequences of opening and closing operationsfollowing simultaneous and maintained openingand closing commands (local and/or remote).
TruckThe poles and operating mechanism are fixedonto a metal supporting and handling truck.The truck is provided with a system of wheelswhich makes the racking-in and racking-outoperations of the apparatus into the switchgearunit with the door closed possible.The truck allows efficacious earthing of the circuit-breaker by means of the metallic structure of theswitchgear.
19
1.7
The conventional mechanical stored energy typeof operating mechanism of the VD4 circuit-breakers can be replaced with an operatingmechanism with magnetic actuator, thereby givingrise to the VM1 series of circuit-breakers.All the characteristics of the circuit-breakersdescribed in this chapter remain unchangedexcept for the operating mechanism.The operating mechanism is based on a greatlyreduced number of components:• Actuator with permanent magnets. The heart
of the operating mechanism consists of themagnetic actuator which carries out the closingand opening operations, and keeps the maincontacts in their positions taken up after theoperation. The magnet transmits the operatingmechanism to the interrupters by means of asingle transmission lever.
• Electronic control device. All the functions(trip, operation, energy charging and watchdog)are carried out from the integrated electroniccontroller. The circuit-breaker is fitted with amultivoltage direct and alternating currentfeeder.
• Capacitors. The energy required to switch theoperating mechanism is obtained by means ofan incorporated capacitor bank. The storedenergy guarantees the complete O-C-O reclos-ing sequence.reclosing sequence.
• Position sensors. The position of the circuit-breaker contacts is detected by means ofelectronic proximity sensors.
Apparatus-operator interfaceThe front part of the circuit-breaker represents theinterface of the apparatus with the user personnel.It is provided with the following accessories:• opening pushbutton• closing pushbutton• operation counter• indicator of the open and closed state of the
circuit-breaker• indicator of the charged and discharged state of
the operating mechanism springs• manual device for charging the operating
mechanism springs• selector for exclusion of the undervoltage
release (optional).
StandardsIEC 62271-100 for the circuit-breaker.
VM1
20
HD4
particularly sensitive to dielectric and dynamicstresses are installed (for example, old cables ortransformers).
PolesThe HD4 circuit-breaker poles use the autopufferbreaking system, combining the compression andself-blast techniques in a single solution.The autopuffer system is the most innovativetechnique in the field of gas circuit-breakers andoriginates from the high voltage apparatus.The combination of the compression and self-blasttechniques allows the best performances to beobtained at all current values. Both are alwayspresent, but whereas the former operates optimal-ly in switching low currents, the latter actseffectively during operation on higher currentvalues. The autopuffer technique allows the use ofa smaller quantity of gas than that required bycircuit-breakers based on other techniques. Forthe same reason, the gas pressure is also consid-erably reduced. The autopuffer technique guaran-tees the insulating withstand voltage and thebreaking capacity up to 30% of the rated one evenwith zero relative pressure.The whole range of HD4 circuit-breakers uses thesame gas pressure for all rated voltage levels (12-17.5-24 kV). SF6 gas pressure level monitoring isnot necessary, since the circuit-breaker poles aresealed-for-life pressure systems and are mainte-nance-free. In any case, they are fitted with apressure control device for checking that thecharacteristicsare not altered due to transport or incorrectoperations.
Operating mechanismThe HD4 circuit-breaker is fitted with a mechanicalstored energy operating mechanism. Trip is freeand therefore allows opening and closing opera-tions independent of the operator. The operatingmechanism spring system can be recharged eithermanually or by means of a geared motor. Theoperating mechanism is of the same type for thewhole series and has a standardised range ofaccessories and spare parts. All the accessorycomponents can easily be replaced by means ofplug-socket connectors.Opening and the closing of the apparatus can becarried out by means of the pushbuttons on thefront of the operating mechanism or by means ofelectric releases (shunt closing, shunt openingand undervoltage).
Gas circuit-breaker
The HD4 medium voltage circuit-breakers usesulphur hexafluoride gas (SF6) to extinguish theelectric arc and as the insulating medium.Thanks to the excellent properties of SF6 gas,interruption of the currents takes place without arcchopping and overvoltages. There is no restrikingphenomenon after interruption and the dielectricproperties following interruption arerecovered extremely rapidly.There are circuit-breakers for all electric powerdistribution applications. They can be particularlyrecommended for the use on capacitor banks,motors, transformers insulated in oil and ininstallations where components which are
The single and double-level switchgear can befitted either with vacuum circuit-breakers or withSF6 circuit-breakers.The ABB vacuum and gas series of circuit-breakers are mechanically interchangeable andthe same switchgear unit can therefore take eithertype of apparatus. Only ABB can offer apparatusbelonging to the two techniques for the wholerange of applications, voltage levels (12-17.5-24 kV), rated current (630...4000 A) and breakingcapacity (16...50 kA), giving the opportunity ofselecting those most suited to the installationcharacteristics and to the feeders to be switchedand protected. The long and proven experience ofABB shows that the two types of circuit-breakersare equally valid and complementary and there-fore allow optimised selection for their use.
21
1.8
HD4-HXA
The circuit-breakers are always fitted with an anti-pumping device to eliminate the possibility ofsimultaneous opening and closing commands,closing commands with springs discharged or withthe main contacts not yet in their run-end position.
TruckThe poles and operating mechanism are fixedonto a metal support and handling truck.The truck is provided with a wheel system whichmakes the operations for racking the apparatusout of and into the switchgear unit possible withthe door closed. The truck allows effective earthingof the circuit-breaker by means of the metallicstructure of the switchgear unit.
Apparatus-operator interfaceThe front part of the circuit-breaker represents theinterface of the apparatus with the user personnel.It is fitted with the following accessories:• Opening pushbutton.• Closing pushbutton.• Operation counter.• Indicator of the circuit-breaker open and closed
state.• Indicator of the charged and discharged state of
the operating mechanism springs.
The range of HD4 circuit-breakers is enriched bythe HXA version.This series of circuit-breakers keeps all thecharacteristics described in this chapter, butstands out for its ability to switch loads with strongunidirectional components.For breaking capacities of 40 kA or lower, they areable to switch loads with unidirectional compo-nents IDC = 100%, up to service voltage 13.8 kV;at 50 kA the unidirectional component percentageIDC is reduced to 50%.They can be used in all installations affected bystrong unidirectional components, but their naturalfield of application is found in switching andprotecting transformers of the auxiliary circuits inpower generating stations.They comply with the IEC 62271-100 Standards.
• Manual charging device of the operating mecha-nism springs.
• Override selector of the undervoltage release(optional).
• LED gas pressure indicator (optional).
StandardsIEC 62271-100 for the circuit-breaker.IEC 60376 for the SF6 gas.
22
V-Contact medium voltage contac-tors are apparatus suitable foroperating in alternating current andare usually used to control feederswhich require a high number ofoperations per hour.They are suitable for operating andprotecting motors, transformers andpower factor correction banks. Fittedwith appropriate fuses, they can beused in circuits with fault levels up to1000 MVA.The electrical life of V-Contactcontactors is defined as being incategory AC3 with 100,000 opera-tions (closing-opening), 400 Ainterrupted current.
The contactor remains in the closed position aslong as the electromagnet remains energised andopens automatically when the auxiliary voltage iscut off.
Operating mechanism with mechanicallatchingThis is a mechanical device which, on closing ofthe contactor, latches up the moving equipmentand keeps the contactor closed with the coils ofthe operating mechanism de-energised.The mechanical latching device includes the shuntopening release for instantaneous service, theopening pushbutton and the release device incase of fuse tripping.
FusesThe contactor is fitted with medium voltage fusesfor protection of the operated feeders.Coordination between the contactor, fuses andprotection unit is guaranteed in accordance withthe IEC 60470 Standards for apparatus in class C.The fuse-holder frame is usually preset for instal-lation of a set of three fuses per phase withaverage dimensions and type of striker, accordingto the following Standards:• DIN 43625.• BS 2692.The following fuses can be applied:• DIN type with a length of 192, 292 and 442 mm• BS type with a length of 235, 305, 410, 454 and
553 mm.The fuse-holder frames are fitted with a device forautomatic opening when even just one fuse blows.This same device does not allow contactor closingwhen even a single fuse is missing.The ABB range of fuses for transformer protectionis called CEF, whereas CEM is the one for motorsand capacitors.
Voltage transformerThe contactor can be fitted with a two-pole voltagetransformer complete with the relevant protectionfuses. The voltage transformer is used to supplythe coils of the contactor operating mechanism.Apart from power supply of the contactor, ito canalso supply other components of the switchgearunit (lamps, signalling devices, auxiliary relays,etc.) up to a maximum power of 50 VA.
The contactors consist of a monobloc of resincontaining the following components:• vacuum interrupters• moving equipment• control electromagnet• multivoltage feeder• accessories and auxiliary contacts.The V-Contact contactors are provided in thefollowing versions:• V7 for voltages up to 7.2 kV.• V12 for voltages up to 12 kV.Both versions are available with the operatingmechanism with electrical or mechanical latching.The V-Contact contactors are mechanicallyinterchangeable with the whole series of ABBcircuit-breakers and the same switchgear unit cantherefore take both types of apparatus withoutdistinction.
The same basic components of the V-Contactcontactor are also used to realise the UniGeartype ZVC compact apparatus. For the specificcharacteristics and the relevant applications referto chapter 3.
Operating mechanism withelectrical latchingClosing of the main contacts is obtained by meansof a control electromagnet. Opening is carried outthanks to the action of a counter spring.
Vacuum contactor
23
1500
2000
1500
kW
kVA
kVAR
5000
5000
4800
3000
4000
3000
1.9
Fuse according to BS Standards
(1) Limited by the fuses.(2) The internal arc with-
stand values are guar-anteed in the compart-ments on the supplyside of the fuses(busbars and appara-tus) by the structure ofthe switchgear and onthe load side (feeder) bythe limiting properties ofthe fuses.
Electrical characteristics
Maximum performances of the contactor with fuses
Motors
Transformers
Capacitors
Maximum load currents of the fuses
Feeder Transformers Motors Capacitors
Rated Fuse Maximum Fuse Maximum Fuse Maximumvoltage load load load
Fuse according to DIN Standards
StandardsIEC 60470 and IEC 60632-1 for the contactor.IEC 60282-1 for the fuses.
Rated voltage
Rated insulation voltage
Rated power frequency withstand voltage
Rated lightning impulse withstand voltage
Rated frequency
Rated short-time withstand current
Peak current
Internal arc withstand current (2)
Maximum rated current of the contactor
3.6
3.6
16
40
50-60
...50
…125
…40
…50
400
kV
kV
kV 1min
kV
Hz
kA(1)
kA
kA 1s
kA 0.5 s
A
12
12
28
75
50-60
…50
…125
…40
…50
400
7.2
7.2
20
60
50-60
…50
…125
…40
…50
400
3.6 kV 200A 160A 315A 250A 450A 360A7.2 kV 200A 160A 315A 250A 355A 285A12 kV 200A 160A 200A 160A 200A 160A
24
Service trucks
The UniGear range is equipped with all the servicetrucks needed to complete the switchgear andrequired for service operations and during mainte-nance work.The trucks are divided into four different types:• Earthing without making capacity.• Earthing with making capacity.• Cable test.• Isolation.
The earthing truck of the main busbars, during theracking-in phase, only lifts the top shutter andearths the contacts connected to the top branchconnections (and therefore to the main busbarsystem) by means of the switchgear structure.The earthing truck of the power cables, during theracking-in phase, only activates the bottom shutterand earths the contacts connected to the bottombranch connections (and therefore to the powercables) by means of the switchgearstructure.These trucks can also be used in the bus-tie unit.In this case, they earth one of the two sides of themain busbar system.
Earthing truck with making capacity (*)These trucks carry out the same function as theearthing switches with making capacity.They consist of circuit-breakers provided with top(earthing of the main busbars) or bottom (earthingof the power cables) terminals only. The contactswithout terminals are short-circuited by means of acopper bar and connected to earth bymeans of the apparatus truck.They keep all the characteristics of the circuit-breakers, such as full making and breakingcapacity on live circuits under fault conditions.They are used to ensure extremely effectiveearthing on circuits stressed by a fault. They allowopening and closing operations to be carried outrapidly with electric remote control.The use of these trucks foresees removal of theapparatus from the switchgear (circuit-breaker orcontactor) and its replacement with the truck.The units preset for use of the earthing trucksmust be provided with a key lock which, whenactivated, prevents its being racked-in.This truck is available in two versions:• Earthing of the main busbar system.• Earthing of the power cables.The earthing truck of the main busbars, during theracking-in phase, only lifts the top shutter andpresets the contacts connected to the top branchconnections (and therefore to the main busbarsystem) for closing to earth by means of operatingmechanism.
Earthing truck without making capacity (*)These trucks carry out the same function as theearthing switches without making capacity.They therefore have no capacity to earth livecircuits in fault conditions.They are used to ensure an additional fixed earth,as is required by some installation service andmaintenance procedures, as a further guaranteefor personnel.The use of these trucks foresees removal of theapparatus from the switchgear (circuit-breaker orcontactor) and its replacement with the truck.The units preset for use of the earthing trucksmust be provided with a key lock which, whenactivated, prevents their racking-in.This truck is available in two versions:• Earthing of the main busbar system.• Earthing of the power cables.
(*) Derived from HD4series.
25
1.10
The earthing truck of the power cables, during theracking-in phase, only activates the bottom shutterand presets the contacts connected to the bottombranch connections (and therefore to the powercables) for closing to earth by means of operatingmechanism.These trucks can also be used in the bus-tie unit.In this case, they earth one of the two sides of themain busbar system.
Power cable test truckThese trucks allow the insulation tests on thepower cables to be carried out without accessingthe feeder compartment or disconnecting thecables from the switchgear.The use of these trucks foresees removal of theapparatus from the switchgear (circuit-breaker orcontactor) and its replacement with the truck.The truck, during the racking-in phase, onlyactivates the bottom shutter and, by means of theconnectors it is fitted with, allows connection of thetest apparatus cables.This truck can only be used in the incoming/outgoing feeders with the door open.
Isolating truck (*)The isolating truck allows the top switchgearcontacts to be connected directly to the bottomones. Connection is made extremely safe by usingthe poles of the circuit-breakers to insulate theconnection busbars from the external environment.In the incoming/outgoing feeder units it connectsthe main busbar system to the power cables,whereas in the bus-tie, to the two sides of thebusbar system.This truck has its application in UniGear switch-gear for making incoming/outgoing feeders withouta circuit-breaker in radial networks, for makingcable connections between two pieces of switch-gear placed in front of each other, in makinginterconnection units and in creating the bus-tieriser configuration with double insulation (in thiscase, both the units are made up of bus-ties, theformer fitted with a circuit-breaker and the latterwith an isolating truck).The units preset for use of the isolating trucksmust be fitted with a key lock which, when activat-ed, prevents its being racked-in.
Main busbar system earthingtruck, without making capacity.
Power cable earthing truck,without making capacity.
Cable test truck.
Main busbar system earthingtruck, with making capacity.
Power cable earthing truck,with making capacity.
Isolating truck.
(*) Derived from HD4series.
26
Switch-disconnector
The DF units are fitted with NAL typeswitch-disconnectors.These units are used to switch andprotect feeders and transformers orthe auxiliary services transformers inelectrical power stations.The NAL switch-disconnectors aremedium voltage air-insulated appara-tus consisting of a fixed support towhich the postinsulators are applied (top andbottom), the system of contacts(fixed and moving) and latchingpliers (of the fuses or of the insulat-ing bars).The switch-disconnector is fitted withtwo systems of moving blade con-tacts, the main one (passed throughby the load current with the switch inthe closed position) and the arc-breaking one (passed through by thecurrent during the opening andclosing operations). This solutions
means the main contacts are not stressed andtherefore keep the electrical characteristics of theapparatus unchanged.During switch-disconnector opening there iscompression of the air by means of the pistonscontained in the top insulator cylinders. At themoment of separation of the contacts, thanks togeneration of a blast of compressed air whichcomes out through special nozzles, the arc iscooled and de-ionised. This leads to a gradualincrease in the arc resistance which determines itsextinction. The movement of the pistons is syn-chronised with that of the arc-breaking contacts ofthe switch-disconnector so as to guarantee thehighest inflow of air at the moment of separation ofthe contacts and thereby obtain certain arcextinction.
The unit can be fitted with insulating bars (NALswitch-disconnector unit) or with medium voltagefuses (NALF switch-disconnector unit with fuses).The NALF switch-disconnector is fitted with anautomatic release mechanism for fuse tripping anduses fuses in accordance with DIN 43625 Stand-ards. The ABB range of fuses for transformerprotection is called CEF. Each unit is fitted with anearthing switch with making capacity for earthingthe cables.
Switch-disconnector control, like that of theearthing switch, comes from the front of theswitchgear by means of manual operation.The position of both pieces of apparatus can beseen directly from the front of the switchgearthrough an inspection window.The unit can be fitted with a set of three currenttransformers or with measurement sensors.
The DF unit consists of two power compartments:busbars and feeder. The latter contains both theswitch-disconnector and the connection terminalsof the power cables.Segregation between the power compartmentstakes place automatically with earthing switchclosure. An insulating shutter creates completeseparation between the fixed contacts of theswitch-disconnector, making the top ones inacces-sible to the operators. This makes maintenanceoperations on the cables and fuses possible,keeping the remainder of the switchgear inservice.
The switch-disconnector, earthing switch andaccess door to the feeder compartment areinterlocked with each other to guarantee maximumsafety for the personnel and correct operation.
Each unit is fitted with an auxiliary compartment,where the instruments and cabling are housed.All the units are accessible from the front andmaintenance and service operations can thereforebe carried out even with the switchgear wall-mounted.
StandardsIEC 60265-1 for the switch-disconnector.IEC 60282-1 for the fuses.
27
1.11
Rated power of the transformer (kVA)
kV 25 40 50 63 80 100 125 160 200 250 315 400 500 630 800 1000 1250 1600
Rated normal current of the fuse (A)
3 10 16 25 25 40 40 63 63 100 100 100 100
5 6 10 16 16 25 25 40 40 63 63 100 100 100 100
6 6 6 10 10 16 16 25 25 25 40 40 63 63 100 100
10 6 6 10 10 16 16 25 25 25 40 40 63 63 100 100
12 6 6 6 10 10 16 16 25 25 40 40 40 63 63 100 100 100
15 6 6 6 10 10 16 16 25 25 25 40 40 40 63 63 100 100
17 6 6 6 6 6 10 16 16 25 25 25 40 40 63 63 63 100 100
20 6 6 6 6 6 10 16 16 16 25 25 40 40 40 63 63
24 6 6 6 6 6 6 10 16 16 16 25 25 40 40 40 63 63
(1) Limited by the fuses.(2) The internal arc withstand values are
guaranteed in the compartment on thesupply side of the fuses (busbars) by thestructure of the switchgear and on theload side (feeder) by the limiting prop-erties of the fuses.
Rated voltage
Rated insulation voltage
Rated power frequency withstand voltage
Rated lightning impulse withstand voltage
Rated frequency
Rated short-time withstand current
Peak current
Maximum rated current of the fuses
Internal arc withstand current (2)
NALF switch-disconnector unit with fuses
Selection table of the fuses for protection transformers
Electrical characteristics
24
24
50
125
50-60
17.5
17.5
38
95
50-60
12
17.5
38
95
50-60
kV
kV
kV 1 m
kV
Hz
…20
…63
63
…25
…25
…100
63
…40
kA (1)
kA
A
kA 1 s
…25
…100
63
…40
Rated power of the transformer (kVA)
kV 25 40 50 63 80 100 125 160 200 250 315 400 500 630 800 1000 1250 1600
Rated normal current of the fuse (A)
3 10 16 25 25 40 40 63 63 100 100 100 100
5 6 10 16 16 25 25 40 40 63 63 100 100 100 100
6 6 6 10 10 16 16 25 25 25 40 40 63 63 100 100
10 6 6 10 10 16 16 25 25 25 40 40 63 63 100 100
12 6 6 6 10 10 16 16 25 25 40 40 40 63 63 100 100 100
15 6 6 6 10 10 16 16 25 25 25 40 40 40 63 63 100 100
17 6 6 6 6 6 10 16 16 25 25 25 40 40 63 63 63 100 100
20 6 6 6 6 6 10 16 16 16 25 25 40 40 40 63 63
24 6 6 6 6 6 6 10 16 16 16 25 25 40 40 40 63 63
28
Instrument transformers
Current transformersThe current transformers are of the type insulated in resin andare used to supply the measurement devices and protectioninstruments. These transformers can have a wound core or abushing bar with one or more cores, with performances andaccuracy classes suitable for the installation requirements.They conform to the IEC 60044-1 Standards.Their dimensions are in accordance with the DIN 42600 NarrowType Standard, in the Medium and Long Size versionsup to 2500A, whereas they are of the toroidal type in the rangeof currents from 3150 A to 4000 A.The current transformers can also be provided with a capacitivesocket for connection to voltage signalling devices.The current transformers are normally mounted on the load sideof the apparatus compartment for measurement of thephase currents of the switchgear unit. Mounting on the supplyside of the apparatus compartment is also possible (busbarapplications) for measuring the busbar currents or for realisingparticular protection schemes. The ABB range of currenttransformers is called TPU.
Toroidal current transformersThe toroidal transformers are of the type insulated in resin andare used to supply measurement and protection devices.These transformers can either be with a closed or openablecore.They can be used both for measuring phase currents or fordetecting the earth fault current.They conform with the IEC 60044-1 Standards.
TPU 1250 A.
TPU 2500 A.
Toroidal current transformer. TPU 3150 A.
29
1.12
Voltage transformersThe voltage transformers are of the type insulated in resin andare used to supply measurement and protection devices. Theyare available for fixed assembly or for installation on removableand withdrawable trucks.They conform with the IEC 60044-2 Standards.Their dimensions are in accordance with the DIN 42600 Narrowtype Standard.These transformers can have one or two poles, with perform-ances and precision classes suited to the functional require-ments of the instruments connected to them.When they are installed on removable or withdrawable trucksthey are fitted with medium voltage protection fuses.The withdrawable trucks also allow replacement of the fuseswith the switchgear in service. Truck racking-out with the doorclosed automatically operates closure of a metallic segregationshutter between the live parts of the switchgear and the instru-ment compartment.Fixed voltage transformers can be installed directly on the mainbusbar system in a dedicated compartment (busbarapplications).The ABB range of voltage transformers is called TJC, TDC,TJP.
Single pole VTs - type TJC.
Double-pole VTs - type TDC.
Single-pole VTs with fuse - type TJP.VT truck with fuses.
30
Measurement sensors
Characteristics of the sensors• Linear response over the whole measurement
field.• Excellent frequency response.• No hysteresis phenomenon.• High degree of immunity to electromagnetic
disturbance.• A single instrument for protection and measure-
ment devices.• Cl.1 overall class of measurement (sensors and
multi-purpose unit).• Any short-circuits or interruptions of the second-
ary circuit do not cause any damage.• The output signal remains very low even in
primary fault situations.• Test terminal blocks are not required.• Connection between the sensor and the meas-
urement and protection instrument is made withshielded cables and connectors.
Benefits provided by the sensors• Improvement of installation selectivity.• More efficient fault location.• Perfecting of fault analysis.• Simplification of engineering tasks.• More rapid and less costly switchgear modifica-
tions and upgrading.• Simple and safe maintenance operations.• Reduction in faults in the measurement and
protection apparatus.• Greater safety for operators thanks to the
absence of high induced currents or voltages inthe secondary circuit.
• Optimisation of maintenance programmes.• Reduction in control and testing times.• Reduction in the number of spare parts.
Introduction of digital technologies in electricalmeasurement and protection instruments hasgreatly changed the performances required oftransformers.The analogue input levels of the instruments havebeen significantly reduced when compared withthose of conventional systems.For this reason, ABB has introduced a new rangeof sensors which optimally covers the characteris-tics of the new generation instruments.The UniGear switchgear can be fitted with KEVCDtype sensors up to 2500 A.Their dimensions are in accordance with the DIN42600 Narrow Type Standard, in the Medium sizeversion.The current and voltage sensors or just the currentsensor can be incorporated at the same time inthe same resin body.The capacitive divider for connection to thevoltage signalling devices is also inserted.
31
1.13
Uout =R2
R1 + R2UpUout = M
dipdt
Voltage sensorThe voltage sensor consists of a resistive dividerthrough which the signal is taken up.The resistive element consists of a bar made ofceramic material.The output signal is a voltage directly proportionalto the primary voltage. The multi-purpose devicereproduces the measurement by means of thepartition ratio.They conform to the IEC 60044-7 Standards.
Current sensorThe current sensor consists of a Rogowski coilwithout the ferromagnetic core.The coil is formed by a uniform winding over aclosed non-magnetic core of constant crosssection. The induced voltage in the secondarycircuit is directly proportional to the variation in thelet-through current. The multi-purpose devicesintegrate the signal to obtain the current value.They conform to the IEC 60044-8 Standards.
Rogowski coil Resistive divider
The output signal (Uout) is a voltage (150 mV at50Hz and 180mV at 60Hz) proportional to thevariation in the current time (Ip); the currentmeasurement is obtained by integrating the signal.
The output signal (Uout) is a voltage directlyproportional to the primary voltage (Up). Thepartition ratio is 10000/1.
Characteristics of the current sensors• No saturation phenomenon.• Precise measurement of the fault currents as
well.• The sensor winding can remain open even with
the switchgear in service.• Just two coils cover the range from 0 to 2500 A.
Characteristics of the voltage sensors• No ferroresonance phenomenon.• The divider is unaffected by the effects of the
direct components.• The sensor can remain connected even during
switchgear voltage tests at power frequency.• A single divider covers the range from 0 to 24
rated kV.
32
Distribution and automation
IntroductionABB protection philosophy
With deliveries of protection releases to more than70 countries, ABB fully understands the need fordiverse protection philosophies as a result of locallegislation, environmental requirements andengineering practice. The main purpose of arelease protection system is to recognize anyabnormal power system conditions, or abnormallyoperating system components. Based on theinformation gathered, the protection system willinitiate corrective actions that return the system toits normal operating state.Release protection doesnot prevent network faults from arising, but it isactivated only when something abnormal hasoccurred in the power system. However, carefulselection of protection functions and methodsimproves the performanceand the reliability of theprotection system, thus minimizing the effects ofnetwork faults and preventing the disturbance fromspreading to the healthy parts of the network.
Advantages of a complete protectionsystemOperating speed, sensitivity, selectivity and reliabili-ty of the protection system need attention.There is a strong correlation between the operatingspeed of the protection system and the damageand danger caused by a network fault.Substation automation provides remote control andmonitoring capabilities, which speed up the locationof faults and the restoration of the power supply.
Fast operation of the protection releases alsominimizes post-fault load peaks, which togetherwith voltage dips increase the risk of the distur-bance spreading to healthy parts of the network.The sensitivity of the protection must be adequateto detect relatively high resistance earth faults andshort circuits in the most distant parts of thenetwork.Reliable selectivity is essential in order to limit theloss of power supply to as small an area aspossible, and to allow the faulted part of thenetwork to be reliably discovered. Correctiveactions can thus be directed to the faulty part of thenetwork, and the supply can be restored as rapidlyas possible.The protection system must have a high degree ofreliability. This also means that if e.g. the circuit-breaker fails to operate, the fault will be cleared bythe back-up protection.Substation automation (SA) puts the operator inperfect control of the substation. In addition, SAsystem improves the power quality of the transmis-sion and distribution network under normal opera-tion, but especially in a situation of disturbance andduring substation maintenance. An SA system orSCADA brings the full benefits of numericaltechnology into protection and control of networks.The terminals are easily set and parameterizedthrough easy and safe access via the operator’sworkplace.
Single-function and multi-function terminals
Proper protection methods and comprehensivefunctionality increase the performance of theprotection system. The definition of comprehensivefunctionality varies with the requirements of theprotected network. While single-functionprotection releases are sufficient for some networkapplications, more complex networks need ad-vanced multi-functional releases.Single-function releases include a set of protectionfunctions for a specific feeder application type. Themain advantages of these releases are redundancyand price. One or more single-function releasesprovide sufficient protection in most applicationareas. Multi-function terminals include a largenumber of protection functions that meet the needsof a lot of applications. In addition, they includecontrol, measurement, power quality monitoringand condition monitoring functions.The use of one single IED incorporating all thesefunctions increases system usability, reduces costsand diminishes the need for wiring in the switch-gear.
33
1.14
Feeder protection
General
The protection functions can be divided into twomajor groups: (1) protection functions that tripcircuit breaker of the faulted feeder on short-circuit, earth fault, etc.; (2) protection functionsthat monitor the operation of the feeder and therest of the network i.e. voltage, frequency andoverload protection functions (alarming / tripping).The basic requirements of the protection systemare adequate sensitivity and operation speed,taking into account the minimum and maximumfault currents occurring in the IED locations,selectivity, inrush currents and the thermal andmechanical strength of the lines behind therelaying point. In many cases, the above require-ments can be fulfilled with non-directional/direc-tional current or impedance measuring functionswith multiple stages. The purpose of the over- andundervoltage protection system is to monitor thevoltage level of the network. If the voltage leveldeviates from the target value by more than thepermitted margin for a specific time period, thevoltage protection system limits the duration of theabnormal condition and the stresses caused.To prevent major outages due to frequencydisturbances, the substations are usuallyequipped with underfrequency protection releases,which in turn control various load-sheddingschemes.
Fig. 1 Comparison between standardand high requirement
feeders
Fig. 2 Typical standard feeder Fig. 3 Typical high requirement feeder
These are just a few examples of the majorprotection functions for feeders. More details canbe found in the technical documentation producedfor the ABB protection releases.
Applications and featuresDepending on the requirements, a suitable IEDtype can be selected and configured in such a waythat an overall solution can be found for differentfeeder types.Generally, the required protection functionality ofthe above feeder types differs greatly betweeneach one depending on, for instance, the charac-teristics of the fault current sources and the typesof more advanced functions that may beneeded to fulfil the basic requirements of theprotection application.A few examples will be given below to illustrate therequirement level.
Recommended productsABB supplies a wide range of feederprotection releases and terminals tofulfil the requirements of each different
application. For an application with standardrequirements and a basic need for additionalfeatures, the REF 610, REX 521 units are excel-lent choices. For applications with higher function-ality requirements, the REF 54_ multifunctionterminals should be selected.
1) Optional arc protection 1) Optional Intermittent E/F protection
34
Fig. 4 Typical standard transformer protection. Fig. 5 Typical high requirement transformer protection.
Transformer protection
General
The power transformer is an important componentand one of the most valuable discrete units in thepower distribution network. High availability of thepower transformer is therefore of particular impor-tance for preventing disturbances in the powerdistribution system. Although high-quality powertransformers are very reliable, insulation break-down faults sometimes occur. These faults -appearing as short-circuits and/or earth faults -generally cause severe damage to the windingsand transformer core. The damage is proportionalto the fault clearing time so the power transformermust be disconnected as quickly as possible. Thepower transformer has to be transported to aworkshop for repair, which is a very time-consum-ing procedure. The operation of a power networkwhere the power transformer is out of service isalways cumbersome. Therefore, a power transform-er fault often constitutes a more severe powersystem fault than a line fault, which can usually berectified fairly quickly. It is extremely important forfast and reliable protection releases to be used todetect transformer faults and initiate tripping.The size, voltage level and importance of the powertransformer determine the quantity and choice ofmonitoring and protection devices to be used to limitthe damage at a possible fault. When compared tothe total cost of the power transformer and the costscaused by a power transformer fault, the cost of theprotection system is negligible.
Distribution and automation
Applications and features
ABB divides transformer applications into standardtransformer protection applications and highrequirement transformer applications. The corefunctionality levels are as follows:
Basic requirement (Typically <1MVA)
• Sudden pressure (Buchholz) –relay• Residual current protection• Overcurrent protection• Earth fault protection• Overload protection• Imbalance protection• Oil level monitor
High requirement (Typically >5MVA)
• Sudden pressure (Buchholz) –relay• Residual current protection• Overcurrent protection• Restricted earth fault (REF) protection• Overload protection• Imbalance protection• Over/Undervoltage protection• Over/underfrequency protection• Oil level monitor
meas urement andsupervision of two-winding power trans-formers and powergenerator-transformerblocks in utility distribu-tion networks. It issuitable for applicationwhere on-load tap-changer control isrequired.Functionality forstandard transformerprotection is provided inthe REF542plusterminal.
Recommended products
The RET 541/543/545 TransformerTerminals are designed for compre-hensive protection, control,
35
1.14
Fig. 6 Typical standard motor protection. Fig. 7 Typical high requirement motor protection.
Motor protection
General
Motor protection is generally expected to provideovercurrent, imbalance, earth-fault and short-circuit protection. However, the fundamental issuefor motors is thermal protection, as overheating isthe worst threat for the motor.Motors need to be protected not only againstelectrical faults but also against any improper wayof running them. ABB solutions focus on advancedthermal protection that prevents improper use ofthe motors. The thermal overloadprotection is needed to protect the motor againstboth short-time and long-time overload and so it isof great importance for the performance of themotor. Overload conditions of short durationmainly occur during motor start-up.There are four crucial elements in thermal motorprotection. (1) The thermal overload protection isthe most important protection function of the motoras it monitors the thermal load and memorizes therelated events. (2) A cumulative start-up timecounter supporting the overload protection limitsthe number of consecutive cold starts. (3) Thethermal stress during any single start-up conditionis monitored by the start-up supervision function,which protects the motor against locked rotorsituations and too long start-up times. (4) Thefourth element in thermal motor protection isthermal protection based on RTD (ResistanceTemperature Detector) sensors. As RTD sensorsdirectly measure the temperature of the stator
Improper use of running motors does not neces-sarily break the equipment but shortens itslifetime.Therefore, a reliable and versatile motor protectionsystem not only protects the motor but alsoprolongs its life-cycle, which contributes to improv-ing the return on motor drive investments.
Applications and features
Thanks to comprehensive communication proto-cols, including the widely-used industrial protocols,such as Modbus RTU/ASCII and Profibus DP, ABBmotor protection releases and terminals can beeasily integrated into various control systems.
Recommended products
The REM 610 is designed forprotection of standard medium andlarge MV asynchronous motors in awide range of motor applications.
The typical size of protected motors ranges from500 kW to 2 MW.The REX 521 and REF542plus are suitable, whenthere is a need to have functionality control inaddition to motor protection.The REM 543/545 machine protection terminalsprovide high-end protection, including residualcurrent protection, for all sizes of asynchronous orsynchronous motors.
36
GeneralIn the complex world of communication, ABB hasmade a great effort to find communication busesand protocols that fulfil the requirements of asecure and efficient data flow. In addition to therecently introduced IEC 61850 protocol, ABB usesLON and SPA communication buses for communi-cation between releases. In addition to these,protocols such as IEC 60 870-5-103, Modbus,Profibus and DNP 3.0 and OPC interface areavailable. Depending on the application area,different protocols are used according to industryde-facto standards.
Utility Applications
IEC 61850
IEC 61850 is a flexible, future-proof standard thatcopes with changing requirements, philosophiesand technologies. The function of the IEC 61850standard is to ensure essential features, such asinteroperability between devices of differentsuppliers, free allocation of functions, adaptabilityto fast changing communication technology andfacility of engineering and maintenance. Thismeans that the long-term stability of the standardsafeguards investments of utilities. From thebeginning, ABB has taken a leading position inelaborating the corresponding standard in the fieldof substation automation.
SPA
The SPA protocol supported by all ABB releasesenables a wide range of distribution and automa-tion functions. The information content that can betransferred is similar to that of IEC 61850. For manyyears, the SPA protocol has been the backbonecommunication protocol for ABB releases and is awell-proven serial bus. To ensure EMI immunity theSPA protocol is run over an fibre optic network.
LON
The LON protocol is a fast bus-based protocolfeaturing both vertical (to a master system) andhorizontal communication. When horizontal com-munication is used, IEDs are able to exchange,such as interlocking information, over the communi-cation bus. This reduces the need for hard wiringbetween devices, thus saving costs. The LON busruns at a substantially higher speed than the serialbuses. ABB has defined extensions to the basicLON protocol, enabling any information appearingin distribution and automation to be efficiently andsecurely transferred. To ensure immunity to EMIdisturbances, the LON bus runs over optical fibres.
IEC 60 870-5-103
IEC 60 870-5-103 is a standard protocol designedexclusively for communication between protectionIEDs and a master system. Allowing IEDs ofdifferent vendors to be connected to a commonmaster system, it is widely supported in distributionand automation. The range of information that canbe transmitted with the IEC 60 870-5-103 protocolis smaller than the information range availablethrough the LON, SPA and IEC 61850 protocols.
DNP V3.0
The DNP protocol based on the IEC 60 870standard family was originally developed by asingle vendor, but has now evolved into an openstandard controlled by a user group. It is designedfor local communication within a substation,between a protection IED and an RTU (whichforwards information to a remote SCADA system).Furthermore, protection IEDs can be connecteddirectly to a remote system using this protocol. TheDNP has a multitude of options enabling it to beoptimized for different types of applications andcommunication environments (it can, for instance,be optimized to run over a slow communicationlink).
Distribution and automation
Communication
37
1.14
Industrial ApplicationsProfibus DP V1
Profibus is a major de-facto standard for connec-tivity to industrial systems. All ABB releases canbe connected to Profibus master systems usingthe SPA-ZC 302 SPA/Profibus converter. The SPA-ZC 302 supports the Profibus DP V1 protocol andcan handle up to 16 SPA devices. The speed ofthe Profibus is comparable with that of LON and issubstantially higher than the speed of the serialprotocols. To ensure EMI immunity, Profibus runsover a double-shielded twisted pair cable.Profibus is generally used when protection IEDinformation is to be transmitted to a controller orPLC.
Modbus
The Modbus protocol was first introduced byModicon Inc. and is a widely accepted communi-cation standard for industrial controllers and PLCs.It is a serial protocol designed for transfer ofbinary and numeric data in a genericformat. The Modbus as such does not recognizethe data model of a distribution and automationapplication (as the IEC 61850 does). The model-ling is done in the application of the Modbusmaster system. Modbus typically uses a twistedpair RS-485 bus network as the transmissionmedium.
OPC
OPC is commonly used tointerconnect systems inindustrial automation applica-tions. A system exchangingdata using OPC consists of anOPC Server (which providesdata and services) and anOPC Client (which receivesdata from and uses theservices of the OPC server).The OPC server and the OPCclient are both softwarecomponents running on PCs.The interaction between anOPC Server and an OPCClient can take place eitherlocally in a PC or over a LAN/WAN computer network (in thelatter case using DCOM as theintermediate protocol). Datafrom protection IEDs
can be made available in different ways throughan OPC interface. One option is to use the SPA/OPC or LON/OPC servers, which collect datafrom protection IEDs using LON or SPA and makethe data available in the OPC environment.Another option is to connect the protection IEDsto the COM 610 gateway. All data in the COM 610can be made available to an OPC client. OPC isusually used when the data from protection IEDsis to be transmitted directly to a control system (asopposed to Profibus and Modbus that usuallysupply data to a controller or a PLC) PC or over aLAN/WAN computer network (in the latter caseusing DCOM as the intermediate protocol).
38
Arc protectionGeneral
An electric arc short-circuit in a switchgearinstallation is normally caused by a foreign objectentering the unit or a component failure. The arccauses an explosion-like heat and pressure effectusually causing vast damage to the switchgearand the operation personnel. An adequate arcprotection system protects the substation againstarc faults by minimizing the burning time of thearc, thus preventing excessive heat and damage.It minimizes material damage and allows powerdistribution to be smoothly and safely restored.The system can also bring cost benefits evenbefore an arc fault occurs. As older switchgear ismore prone to arc faults, an arc protection systemwill effectively extend the life of the switchgear andmake more of investments. But what is even moreimportant, this technology can help save lives.Applications and featuresSources of arcing may beinsulation faults, malfunction-ing devices, defective bus orcable joints, overvoltage,corrosion, pollution, moisture,ferroresonance (instrumenttransformers) and evenageing due to electricalstress. Most of these arc faultsources could be preventedby sufficient maintenance.However, in spite of theprecautions taken, humanerrors can lead to arc faults.Time is critical when it comesto detecting and minimizingthe effects of an electric arc.An arc fault lasting 500 msmay cause severe damage to the installation.If the burning time of the arc is less than 100 msthe damage is often smaller, but if the arc isextinguished in less than 35 ms its effect is almostnegligible. Generally, protection releases appliedare not fast enough to ensure safe fault clearancetimes at arc faults. The operation time of theovercurrent release controlling the incomingcircuit-breaker may, for instance, have to bedelayed by hundreds of milliseconds for selectivityreasons. This delay can be avoided by installing anarc protection system.The total fault clearance time can be reduced to amax of 2.5 ms plus the circuit breaker contacttravel time.
Recommended products
The REA 101 arc protection system with its REA103, REA 105 and REA 107 extension units, aredesigned to be used for protection of medium andlow-voltage air-insulated switchgear.The REA 101 central unit type operates independ-ently or together with other REA 101 units.REA is the fastest arc protection system on themarket, providing tripping times down to 2.5 ms.REA is equipped with a fast integrated overcur-rent-sensing element and therefore works inde-pendently of other feeder protection units. TheREF 610 feeder protection release includes anoptional arc protection function for the feedercompartment.
Distribution and automation
Fig. 8 Typical setup with REA 101 and subunits 103
Furthermore, on cable compartment faults, auto-reclosures can be eliminated by using arc protec-tion.
39
1.14
Selection guide
Application
Feeder application ■ ■
High requirement feeder application ■ ■
Transformer application ■ ■
High requirement transformer application ■
Motor protection ■ ■ ■ ■
High requirement motor application ■
Generator & synchronous motor ■
Distance protection ■
Arc protection for feeder cubicle ■ ■
Arc protection system
Communication
IEC 60870-5-103 ■ ■ ■ ■ ■
IEC 61850 ■* ■* ■* ■* ■* ■*
DNP 3.0 ■ ■ ■ ■
SPA ■ ■ ■ ■ ■ ■
LON ■ ■* ■ ■ ■ ■*
Modbus ■ ■ ■ ■ ■
Profibus ■* ■* ■* ■* ■* ■*
Additional functions
Fault locator ■
Web interface ■
CAN interface ■
On load tap changer control ■
Disturbance recording ■ ■ ■ ■ ■ ■
Withdrawable release mechanics ■ ■
Condition monitoring ■ ■ ■ ■ ■
Single line diagram HMI** ■ ■ ■
Remote control ■ ■ ■ ■
Power quality monitoring ■ ■
Sensor inputs ■ ■ ■ ■
Auto re-closure 5 shots 3 shots 5 shots
RTD*** inputs 8 8 8 6
* With interface adapter** HMI - Human Machine Interface
*** RTD - Resistive Temperature Detector
REF 54_ REF 610 REX 521 RET 54_ REM 54_ REM 610 REA 10_
40
Automatic transfer systems
Single-line diagram ofUniGear switchgear withREF542plus architectureapplied, suitable for carryingout automatic and manualtransfer (ATS), as well as theswitchgear protections andmeasurements.
Automatic transfer systems are used to ensuremaximum service continuity, supplying the powerusers uninterruptedly.All this is possible using various systems based ondifferent kinds of techniques.The most common of these are given below, withthe relevant average transfer times:
• Delayed: 1500 ms
• Depending on the residualvoltage: 400-1200 ms
• Synchronised (ATS): 200-500 ms
• High speed (HSTS): 30-120 ms
The first two systems are the simplest and canalso be made with conventional logics and instru-ments. They guarantee average transfer times andcan therefore be used in installations wherevoltage gaps are not particularly critical.On the other hand, the other two systems (ATS –Automatic Transfer System and HSTS – HighSpeed Transfer System) require microprocessor-based apparatus with high technological content.They guarantee fast transfer times and theirapplication is in plants where the process isparticularly critical. Transfers which are notextremely fast would cause serious malfunctionsor stoppage of the process itself.ABB is able to offer all the transfer systems, fromthe simplest to the most complex.
ATSThe REF542plus unit can be used in mediumvoltage switchgear to manage automatic andmanual transfer between two different incomingfeeders.The time needed for automatic transfer carried outby means of the REF542plus unit is between 200and 300 milliseconds (including the circuit-breaker operating times). This time can vary withinthe range indicated in relation to thecomplexity of the software transfer logics.Switchgear equipped with REF542plus, suitablyprogrammed, are complete and efficient systemsable to manage transfer between one powersupply system and an alternative one, or toreconfigure the network, passing from doubleradial distribution to a simple system, in a fullyautomatic way.It is also possible to carry out the same operationmanually from a remote control station, or from thefront of the switchgear with supervision of the userpersonnel.Manual transfer means making the passageparallel: by means of the synchronism controlfunction (synchro-check – code 25) implementedfrom the REF542plus, the power supply lines areclosed simultaneously with synchronisation of thevoltage vectors to then return to being disconnect-ed when transfer has taken place. The applicationsdescribed do not require additional instruments.
41
1.15
Unit 1 Unit 2
N.O. N.C.
Unit 1 Unit 2
N.C. N.C.
N.O.
HSTSThe HSTS System (High Speed Transfer System) is the ideal solution for critical industrial processeswhere the lack of electric power even for just one or two cycles can cause stoppage of the productionprocess and considerable damage to equipment.This system, which is fully integrated in the switchgear, is able to transfer distribution of power from themain switchgear unit to an alternative emergency supply in a few milliseconds. This avoids long andcostly machine stoppages, damage to production equipment, and dead production restarting times.The HSTS SUE 3000 system makes it possible to obtain transfer times equal to 100 ms with the use ofall conventional circuit-breakers and 30 ms with VM1 circuit-breakers equipped with a magnetic actuatorin the high speed version and up to 1250 A.
HSTS system in the configu-ration with two circuit-break-ers without bus-tie: when thelack of voltage in the mainpower supply unit of theswitchgear is detected, theclosing command of the re-serve unit and the openingcommand of the main unitare launched simultane-ously.
HSTS system in the configu-ration with three circuit-breakers with bus-tie: whenthe lack of voltage in one ofthe two power supply unitsis detected, the closing com-mand of the bus-tie and theopening command for theswitchgear unit without volt-age are launched simultane-ously.
42
Typical units and technical data
Single-line diagram of typical units
IF - Incoming/outgoingfeeder
BT - Bus-tie R - Riser RM - Riser with measure-ments
M - Measurements IFD - Direct incoming/outgoing feeder
IFDM - Direct incoming/outgoing feederwith measurements
DF - Switch-disconnectorunit
Rem
ovab
le
With
draw
able
With
draw
able
Rem
ovab
le
With
draw
able
43
1.16
Single-line diagram of the busbar applications
Current transformers Voltage transformers Duct entry Earthing switch
Circuit-breaker Contactor Switch-disconnector
Isolating barSwitch Socket and plug
Voltagetransformers
Currenttransformers
Fuse Cable entryEarth Busbar entry
Key to components
Standard components
Accessories
Alternative solutions
Graphical symbols
44
Typical units and technical data
... 12 kV - ... 31.5 kADepth (mm) 1340 1340 1340Height (mm) 2100/2200/2595 (1) 2100/2200/2595 (1) 2100/2200/2595 (1)Height with gas exhaust duct (mm) 2675 2675 2675Width (mm) 650 800 1000Rated current (A) 630 1250 1600 2000 2500 630 1250 1600 2000 2500 630 1250 1600 2000 2500IF Incoming/outgoing (3) (2) (2)BT Bus-tieR RiserRM Riser with measurementsM MeasurementsIFD Direct incoming/outgoingIFDM Direct incoming/outgoing with measurementDF Switch-disconnector unit (4)
... 12 kV - ... 50 kADepth (mm) 1340 1390 1340 1390Height (mm) 2100/2200/2595(1) 2100/2200/2595(1) 2100/2200/2595(1) 2100/2200/2595(1)Height with gas exhaust duct (mm) 2675 2675 2675 2675Width (mm) 800 800 1000 1000Rated current (A) 630 1250 1600 2000 2500 3150 3600 4000 630 1250 1600 2000 2500 3150 3600 4000IF Incoming/outgoing 40kA (2) (2)BT Bus-tie 40kAR RiserRM Riser with measurementsM MeasurementsIFD Direct incoming/outgoingIFDM Direct incoming/outgoing with measurement
... 17.5 kV - ... 31.5 kADepth (mm) 1340 1340 1340Height (mm) 2100/2200/2595 (1) 2100/2200/2595 (1) 2100/2200/2595 (1)Height with gas exhaust duct (mm) 2675 2675 2675Width (mm) 650 800 1000Rated current (A) 630 1250 1600 2000 2500 630 1250 1600 2000 2500 630 1250 1600 2000 2500IF Incoming/outgoing (2) (2)BT Bus-tieR RiserRM Riser with measurementsM MeasurementsIFD Direct incoming/outgoingIFDM Direct incoming/outgoing with measurementDF Switch-disconnector unit (4)
... 17.5 kV - ... 40 kADepth (mm) 1340 1390 1340 1390Height (mm) 2100/2200/2595(1) 2100/2200/2595(1) 2100/2200/2595(1) 2100/2200/2595(1)Height with gas exhaust duct (mm) 2675 2675 2675 2675Width (mm) 800 800 1000 1000Rated current (A) 630 1250 1600 2000 2500 3150 3600 4000 630 1250 1600 2000 2500 3150 3600 4000IF Incoming/outgoing (2) (2)BT Bus-tieR RiserRM Riser with measurementsM MeasurementsIFD Direct incoming/outgoingIFDM Direct incoming/outgoing with measurement
45
1.16
B
C
D
A
E
C
A
E
D
Notes(1) The height of the unit is a function of the height of the instrument compartment, available in the 580, 705 and 1100
mm versions. The instrument compartment of the unit from 3150A to 4000A is only available in the 705 and 1100mm versions.
(2) Version only available with vacuum circuit-breakers.(3) For the characteristics of the unit equipped with contactor refer to pages 20-21.(4) For the characteristics of the unit equipped with switch-disconnector refer to pages 24-25.
Unit compartmentsA ApparatusB Main busbarsC FeederD InstrumentsE Gas exhaust duct
... 24 kV - ... 25 kADepth (mm) 1560 1560Height (mm) 2200/2325/2720 (1) 2200/2325/2720 (1)Height with gas exhaust duct (mm) 2775 2775Width (mm) 800 1000Rated current (A) 630 1250 1600 2000 2500 630 1250 1600 2000 2500IF Incoming/outgoing (2) (2)BT Bus-tie (2)R RiserRM Riser with measurementsM MeasurementsIFD Direct incoming/outgoingIFDM Direct incoming/outgoing with measurementDF Switch-disconnector unit (4)
Width Depth
Hei
ght
(1)
Hei
ght w
ith g
as e
xhau
st d
uct
46
47
2UniGear 550
Page Chap.
Description 48 2.1
Characteristics 50 2.2
Typical units and technical data 52 2.3
48
The latest item in the large family of UniGearproducts is the panel called UniGear 550 whichmirrors all the construction characteristics of thestandard panel.UniGear 550 is available up to a maximum panelcurrent of 1250A: The circuit-breaker designatedfor this product is called Vmax/L.The peculiarity of this panel is its size. In fact, itonly measures 550 mm in width which makes it avery compact and versatile product.It has been built so that it can be connecteddirectly to the standard panel. In fact, it has thesame overall dimensions (height and depth) andthe same omnibus busbars up to a maximumcurrent value of 4000A.For this panel, too, positioning against the wall ispossible. In fact, all the putting into service andmaintenance operations can be carried out directlyfrom the front.Accessing the cable area is particularly convenientby easily removing the base of the circuit-breakercompartment. In this way, accessibility is in-creased.As a standard solution, it is possible to connect upto three single-pole cables per phase (maximumcross-section of 185 mm²), or two cables perphase (maximum cross-section of 300 mm²).
Description
The connection height of the cables in relation tothe floor is 600 mm.
UniGear 550 uses toroidal transformers as thestandard solution, which are fixed onto a “CT Rod”.As an optional solution, the transformers can beinserted on a DIN rail.The panel has been built to be able to insert thefixed voltage transformers, positioned on the frontof the panel itself. The capacitive signal for indicat-ing voltage present is connected directly to theinsulators which support the busbars on the cableside. The surge arresters can also be inserted inthe cable area.
The UniGear 550 switchgear is fitted with all theinterlocks and accessories needed to guaranteetop level safety and reliability for the installation andfor the operators.
UniGear 550 has undergone all the tests requiredby the International Standards (IEC) and localstandards (for example the GB, Chinese andRussian GOST standards).
49
2.1
Rated voltage
Rated insulation voltage
Rated power frequency withstand voltage
Rated lightning impulse withstand voltage
Rated frequency
Rated short time withstand current
Peak current
Internal arc withstand current
Main busbar rated current (1)
Branch connection rated current
12
12
28
75
50-60
31.5
80
31.5
630…4000
630 - 1250
12
12
38
95
50-60
31.5
80
31.5
630…4000
630 - 1250
17,5
17,5
38
95
50-60
31.5
80
31.5
630…4000
630 - 1250
kV
kV
kV 1m
kV
Hz
kA 3s
kA
kA 1s
A
A
Electrical characteristics
(1) Up to 4000A if coupled with other UniGear units.
Apart from this, UniGear 550 is completing theseries of certifications required by the regulationsof the major shipping registers (LR, DNV, RINA,BV and GL) for use of the switchgear in marineinstallations.In accordance with the IEC 62271-200 Standard,UniGear 550 is defined as follows:
– PM (Partition metallic): i.e. it is provided withmetallic shutters and partitions between theoperating parts and an open compartment.
– LSC2B (Loss of service continuity): service ofthe main busbar and of the cable compartmentis guaranteed when a normal maintenanceoperation is to be carried out in one of thecompartments of the main circuit (e.g. circuit-breaker compartment).
– IAC AFLR (Internal arc classified): UniGear 550is classified as IAC AFLR, i.e. it is accessiblefrom the front, side and rear having respectedthe five criteria during the internal arc tests.
50
Characteristics
These units are designed to be equipped with thefollowing instruments:– Ring core type current transformer (standard).– Block type current transformer (optional).– Bushing type current transformer (optional).
Ring core type of current transformerThanks to the new digital protection and measur-ing instruments, the use of low power measuringinstruments can easily be extended to primarydistribution switchgear as well.These current transformers are arranged on asupport inside the switchgear (CT rod) and abovethe cable terminals to be unaffected by thefollowing choices: number of cables, cross sectionand type of terminations.These CT rods are designed to be equipped witha maximum of two current transformers per phase(metering and protection) and with the followingdimensional requirements:– minimum internal diameter: 30 mm;– maximum external diameter: 190 mm;– maximum height: 80 mm.
Ring core type current transformer.
Block type current transformerAs an alternative to the above specified currentmeasuring instruments, application of a set perphase of block type current transformers, currentsensors and combi-sensors is possible with adedicated design.
Their use is required in the case of a great needfor just a few units, such as fiscal metering onincoming feeders (Class 0.2), residual currentprotection on transformer feeders, etc.The use of block type current transformers will inany case allow application of ring core typecurrent transformers on cables.
Bushing type current transformerIn a large part of the market, and especially inthose strongly affected by BS concepts, there iswidespread use of the bushing type currenttransformers.
Bushing type current transformer.
Block type current transformer.
51
2.2
ST1-UG Earthing SwitchThe 550 panel is equipped with ST1-UG typeearthing switch. This device is a patented switchwith rectilinear movement.It is fitted with a snap action operating mechanismfor positive high speed closing and is sized toconduct the rated short circuit making currentwhen close to underload.The speed of the snap action closing operation isindependent of controls.The switch is equipped with an earthing bladewhich connects the three phases via the earthingpins placed on the copper bars of the cableconnecting system.The earthing bar is electrically connected to earthby a stranded copper conductor.The snap action closing mechanism of the earth-ing switch functions independently of the rotationof the drive shaft.The switching speed and torque achieved areindependent of the action of the operating mecha-nism.On the other hand, in the opening process, thetoggle springs have no effect on the speed ofcontact separation.A manual operating lever is provided for operationof the switch.
The switch has been tested at two closing opera-tions at 100% of the rated short-circuit makingcurrent. The device is provided with auxiliaryswitches for signalling the open and closedpositions, operated by the rod mechanism.
The following are available on request:– Locking magnet– Key locks for open and closed positions– Padlock.
52
Single-line diagram of the typical units
IF - Incoming / Outgoing feeder BT - Bus-tie R - Bus Riser RM - Bus Riser withmeasurements
M - Measurements IFD - Direct Incoming /Outgoing
IFDM - Direct Incoming /Outgoing withmeasurement
Typical units and technical data
Rem
ovab
le
Rem
ovab
le
Rem
ovab
le
Rem
ovab
le
With
draw
able
53
Unit width 550mm
Rated current [A] – 630 1250
Incoming / Outgoing feeder
Incoming / Outgoing with measurements
Bus Tie
Bus Riser
Bus Riser with measurements
Measurements
Direct Incoming / Outgoing
Direct Incoming / Outgoing with measurement
Switch-disconnector unit
12-17.5 kV
IF
IFM
BT
R
RM
M
IFD
IFDM
DF
– Depth (mm): 1340– Height (mm): 2200 - (1) 2595 with higher instrument compartment)– Height with gas exhaust duct (mm): 2675
2.3
Unit compartmentsA ApparatusB BusbarC FeederD InstrumentsE Gas exhaust duct
Width Depth
Hei
ght (
1)
Hei
ght w
ith g
as e
xhau
st d
uct
54
55
3Double Level UniGear
Page Chap.
Description 56 3.1
Characteristics 58 3.2
Typical units and technical data 60 3.3
56
IF IF
IF IF IF IF
IF IF
IF IF IF
RM RMBT
630A
1250A
630A 630A
630A
1250A
1250A
IF
IF
IF
IF
Description
Its use is recommended in installa-tions with a high number of feeders,fitted with either circuit-breakers orcontactors. It can be used as a motorcontrol center for applications up to12 kV.All the electrical characteristics of thedouble and single-level units areidentical. The overall rated current ofthe busbar system is given by thesum of the currents of the two topand bottom half-busbars. The double-level units can becoupled directly to single-level units,with the possibility of extension atboth ends of the switchgear.The switchgear requires access fromthe rear for the installation andmaintenance procedures, whilst allthe service operations are carriedout from the front.The double-level UniGear switchgearcan be used in two typical configura-tions:• Complete with double-level.• Compound with simple and
double-level.
UniGear is a single busbar systemswitchgear in the double-levelconfiguration. Each panel consists oftwo completely independent super-imposed units and is functionallyidentical to two single-level unitsplaced side by side.Thanks to the numerous typical unitsavailable, the switchgear can besuitably configured to satisfy allinstallation requirements.Each unit can be equipped withcircuit-breakers or contactors, as wellas with all the accessories availablefor conventional switchgear units. Allthe significant components areidentical to those used for the single-level units and therefore the sameservice and maintenance proceduresare guaranteed.The double-level UniGear switchgearmainly stands out for its efficient useof space. All the configurations allowa drastic reduction in the spaceoccupied, with special regard to thewidth of the switchgear (30...40% intypical configurations).
Complete double-level con-figuration.
57
3.1
The complete solution only usesdouble-level panels to realise all thetypical units: incoming feeders, bus-tie, riser, busbar measurement andoutgoing units.The compound one, on the otherhand, uses both the simple anddouble-level solution: the former forthe incoming feeders, bus-tie andriser compartments, the latter for thebusbar measurement and outgoingunits.The complete double-level solutionachieves the maximum objective ofreducing dimensions and can beused for relatively limited ratedcurrents (1600 A maximum current ofthe incoming feeders). It is normallyused to make local distributionswitchgear, with a limited number ofoutgoing feeders.The field of application of thecompound solution is, on the otherhand, for main distribution switch-gear, with high rated currents(3150 A maximum current of theincoming feeders) and numerousoutgoing feeders.
Electrical characteristics
Rated voltage
Rated insulation voltage
Rated power frequency withstand voltage
Rated lightning impulse withstand voltage
Rated frequency
Rated short-time withstand current
Peak current
Internal arc withstand current
Main busbar rated current
Branch connection rated current
17.5
17.5
38
95
50-60
…40
…100
…40
-
…1600
630
1000
1250
1600
12
12
28
75
50-60
…50
…125
…40
…50
…1600
630
1000
1250
1600
7.2
7.2
20
60
50-60
…50
…125
…40
…50
…1600
630
1000
1250
1600
kV
kV
kV 1min.
kV
Hz
kA 3s
kA
kA 1s
kA 0.5s
A
A
Compound configurationwith simple and double level.
58
Characteristics
CompartmentsEach panel consists of two superimposed units [1st
level and 2nd level] and each unit is therefore madeup of three independent power compartments:apparatus [A], busbar [B] and feeder [C].There is metallic segregation between all thecompartments.In its middle part, the panel is fitted with a com-partment to take the auxiliary instruments of boththe units [D]. This solution means the machine-user interfacing apparatus is at a convenientheight. In the top part of the panel, an additionalcompartment is available to house any furtherinstruments provided [d].The arc-proof switchgear is normally fitted with aduct for evacuation of the gases produced by anarc [E]. Each compartment of the unit placed onthe 2nd level is fitted with a flap on the top of it. Thepressure generated by the fault makes this open,allowing the gas to pass into the duct.The gases produced by faults generated in thepower compartments of the unit placed on the 1st
level are evacuated towards the main duct bymeans of a dedicated duct placed laterally to theswitchgear [e]. Each compartment of the unitplaced on the 1st level is fitted with a flap posi-tioned on the side of the switchgear. The pressuregenerated by the fault makes this open, allowingthe gas to pass into the duct. This solution meansthe units placed on the 2nd level are notinvolved in the effects of the fault.The apparatus compartments are accessible fromthe front. Door closing of these compartments isavailable in two versions, with screws or centralhandle. Removal of the apparatus from theswitchgear (circuit-breakers, contactors andmeasurement truck) placed on the two levels andfrom its relative compartments takes place bymeans of a single dedicated fork-lift truck. Thistruck can also be used for the same proceduresfor the single level units.The busbar and cable compartments are accessi-ble from the rear of the switchgear by means ofremovable panels.All the normal service operations are carried outfrom the front, whereas maintenance and start-upoperations also require access from the rear of theswitchgear.The fact that the switchgear is clearly identified asbelonging to the two superimposed units, makes itimpossible to carry out incorrect operations.
The characteristics of the busbar system, branchconnections, earthing busbar, earthing switch,insulator bushings and shutters are the same asthose for the single-level units. A maximum of sixsingle or three-core cables per phase can beused depending on the rated voltage, on the unitdimensions and on the cross-section of the cables.
ConfigurationsThe typical units available allow the most suitableconfigurations for the installation requirements.The incoming/outgoing feeder panel [IF] is the onemost widely used: both switchgear levels consistof units of this type and can be used both asincoming and outgoing feeders.The bus-tie [BT] and riser [R] units are used tomake complete double-level switchgear. Theseunits are positioned on the 2nd level, whereas theincoming/outgoing feeder units are included in the1st level. The bus-tie units can be fitted withcurrent transformers on the load side of the circuit-breaker for busbar measurement. Installation ofthe current transformers on the supply side is alsopossible to realise special protection schemes.The riser compartment is also available in theversion with withdrawable instrument truck withvoltage transformers with fuses [RM].The compound configuration with simple anddouble-level requires connection between the twopieces of switchgear by means of the connectionunit. This unit makes all the connections betweenthe two types of switchgear (busbars, earthingbusbar, gas exhaust duct, ducts for connection ofthe auxiliary circuits) and can integrate theearthing switch of the busbars [J] and also thewithdrawable instrument truck with voltage trans-formers with fuses [JM]. These units are posi-tioned on the 2nd level, whereas the incoming/outgoing feeder units are included on the firstlevel.
59
3.2
1
2
3
4
4
1
2
3
2° Level
1° Level
1 Door of the apparatus compartment2 Racking-in/racking-out operation3 Earthing switch operation4 Control unit
60
Typical units and technical data
Single-line diagram of typical units
2° L
evel
1° L
evel
IFIncoming/outgoingfeeder
BTBus-tie
RRiser
RMRiser withmeasurements
JConnection unit
JMConnection unit withmeasurements
IFIncoming/outgoingfeeder
IFIncoming/outgoingfeeder
IFIncoming/outgoingfeeder
IFIncoming/outgoingfeeder
IFIncoming/outgoingfeeder
IFIncoming/outgoingfeeder
With
draw
able
With
draw
able
Key to components
Standard components
Accessories
Alternative solutions
61
3.3
B1
C1
D
A2
EB2
C2
A1A1
D
A2
d d
e
... 12 kV - ... 50 kADepth (mm) 1976Height (mm) 2698 (1)Height with gas exhaust duct (mm) 2698 (1)Width (mm) 750 750 900 900Rated short-time current (kA) ... 31.5 .. 31.5 ... 50 ... 50Rated current (A) 630 1000 1250 16002nd IF Incoming/outgoing (2)1st IF Incoming/outgoing (2)
2nd B T Bus-tie1st IF Incoming/outgoing
2nd R Riser1st IF Incoming/outgoing
2nd R M Riser with measurements1st IF Incoming/outgoing
2nd J Connection 1250A1st IF Incoming/outgoing (2)
2nd J M Connection with measurements 1250A1st IF Incoming/outgoing (2)
... 17.5 kV - ... 40 kADepth (mm) 1976Height (mm) 2698 (1)Height with gas exhaust duct (mm) 2698 (1)Width (mm) 750 750 900 900Rated short-time current (kA) ... 31.5 .. 31.5 ... 40 ... 40Rated current (A) 630 1000 1250 16002nd IF Incoming/outgoing1st IF Incoming/outgoing
2nd B T Bus-tie1st IF Incoming/outgoing
2nd R Riser1st IF Incoming/outgoing
2nd R M Riser with measurements1st IF Incoming/outgoing
2nd J Connection 1250A1st IF Incoming/outgoing
2nd J M Connection with measurements 1250A1st IF Incoming/outgoing
Notes(1) The height of the switchboard in the compound configuration with simple and double-level is the same as that of the double-level unit.(2) For the characteristics of these units equipped with contactor refer to page 22.
Unit compartmentsA ApparatusB Main busbarsC FeederD InstrumentsE Gas exhaust ductWidth Depth
Hei
ght
62
63
4Double Busbar System UniGear
Page Chap.
Description 64 4.1
Characteristics 66 4.2
Typical units 68 4.3
Technical data 70 4.4
64
Most switchgear used in installations with normalservice conditions is based on single busbarsystems.When compared with double busbar switchgear,single busbar switchgear is definitively easier tooperate and maintain, requires less space and thetotal cost of the installation is lower (equipment,site procedures, maintenance, square metres,etc.).
The use of double busbar switchgear may benecessary when some of the following featuresare required:– Operation of incoming feeders with non-syn-
chronised circuit breakers.– Load shedding of outgoing feeders with a
different level of importance during emergencyconditions.
– Isolation of particular outgoing feeders from thenormal network.
– Outgoing feeders balancing on two busbarsystems during normal service.
– Flexibility during inspection and maintenanceprocedures without load interruption.
– Extension without switchgear shutdown.
The double busbars systems are based on twodifferent schemes:– Two busbars systems, two line disconnectors
and one circuit breaker (pure double busbarssystem).
– Two busbars systems, two circuit breakerscompartments with one or two circuit breakers(duplex system).
Both the schemes provide full busbar systemredundancy (physical isolation between sourcebusbar systems) and allow uninterrupted andreliable service conditions.
The first solution has two main advantagescompared with the second one:– Free access to one busbar system during
maintenance operations while the other is inservice.
– Fast switching between the two busbar systemsduring emergency situations thanks to the useof line disconnectors.
Single Busbar Section.
Description
65
4.1
Electrical characteristics
24
24
50
125
50-60
...25
...63
…25
1250...2500
630...2000
–
12
12
28
75
50-60
...31.5
...80
…31.5
1250...4000
630...3150
3600...4000
kV
kV
kV 1min.
kV
Hz
kA 3s
kA
kA 1s
A
A
A
17.5
17.5
38
95
50-60
...31.5
...80
…31.5
1250...4000
630...3150
3600...4000
Rated voltage
Rated insulation voltage
Rated power frequency withstand voltage
Rated lightning impulse withstand voltage
Rated frequency
Rated short time withstand current
Peak current
Internal arc withstand current
Main busbars rated current
Branch connection rated current
Branch connection rated current with forced ventilation
The second solution has two main advantagescompared with the first one:
– Incoming feeders and very important outgoingfeeders can be equipped with two circuit-breakers in order to allow apparatus redundancyas well.
– Circuit-breaker maintenance and testing withoutfeeder shutdown.
– Fewer number of components and less switchingapparatus.
Thanks to the numerous typical units available, theswitchgear can be suitably configured to satisfy allinstallation requirements.
Double Busbar Section.
Each unit can be equipped with circuit-breakers orcontactors, as well as with all the accessoriesavailable for conventional switchgear units.All the significant components are identical tothose used for the single level and double levelunits and therefore the same service and mainte-nance procedures are guaranteed.The units can be arranged as required by theinstallation requirements, but, according to thetechnical literature, the switchgear must beconfigurable as per the following two schemes:– Single busbar section– Double busbar section
66
CompartmentsEach panel is made up of four independent powercompartments: apparatus (A), busbar 1 (B1),busbar 2 (B2) and feeder (C). There is a metallicsegregation between all the compartments.In its front/top part the panel is fitted with a com-partment to take the auxiliary instruments (D).The arc-proof switchgear is normally fitted with aduct for evacuation of the gases produced by anarc (E).Each compartment of the unit is fitted with a flap onthe top of it. The pressure generated by the faultmakes this open, allowing the gas to pass into theduct.The apparatus compartment is accessible from thefront. Door closing of these compartments isavailable in two versions, with screws or centralhandle.Removal of the apparatus from the switchgear(circuit-breakers, contactors and trucks measure-ments) and from its relative compartments takesplace by means of a single dedicated truck.The busbar and cable compartment are accessiblefrom the rear of the switchgear by means ofremovable panels.All the normal service operations are carried outfrom the front, whereas maintenance and start-upoperations also require access from the rear of theswitchgear.It is not possible to achieve full front access to allcompartments and components with the doublebusbar system switchgear, so installation notstanding against the wall is mandatory.
Line disconnectorsIF unit line disconnectors are designed to act astwo positions switches - open and closed positions- and operation is manual (e.g. without springs).The opening and closing operation of the linedisconnector is operated from the front of thepanel.The position of the line disconnector is indicated onthe front of the panel with reliable indicators.The line isolators are clearly separated and therelevant busbar compartments must be segregatedfrom each other in order to achieve the following:A fault generated in one compartment (e.g. insula-tion discharge) will not generate any damage to theothers or require the shutdown of the unit.It should be possible to carry out maintenance andalso extend the switchgear with additional unit/s,keeping one of the two busbars systems energised.They are provided of limit switches for the positiondetection.The line disconnectors can be operated manuallyor, as an option, motor operated. Motor operation islocked while the manual-operating crank is insertedinto the operating slot.The line disconnectors are provided with thenecessary interlocking facilities.
Characteristics
67
4.2
The interlocks between the two line disconnectorsand the circuit breaker are implemented by meansof locking magnets. This solution allows maximumflexibility and the required service conditions.The line disconnector consists of a moveablecopper tube included inside an epoxy insulator.Electrical contact is guaranteed by two or fourconnection springs (depending on the rating of thedisconnector). Additional protective insulating capsare mounted on both sides of the insulator, thusproviding the device with a high level of reliability.
1 – Door of the apparatus compartment2 – Control unit3 – Racking-in/racking-out operation4 – Earthing switch operation5 – Open/closed line disconnector B16 – Open/closed line disconnector B2
68
Typical units
Single-line diagram of the typical units
IF - Incoming/Outgoing IF and IFM - Busbar A Duplex IF and IFM - Busbar B Duplex
BTT - Transv. Bus Tie M - Metering BTL - Longitudinal Bus Tie
69
4.3
Single-line diagram of the typical units
RL - Bus Riser Long. RLM - Bus Riser Long. with Metering
Busbar applications
Top-mounted VTs Top-mounted earthing switch Top entry duct
70
Technical data
– Depth (mm): 2021– Height (mm): 2075 - (2595 with higher instrument compartment)– Height with gas exhaust duct (mm): 2700
IF and IFM duplex feeders, M, BTL, RL and RLM will be available for both A and B busbar system connections.
12-17.5 kVUnit width (mm) 650
Rated current (A) 630 1250 1600 2000 2500 3150 3600 4000
IF Incoming/outgoing feeder
IF Incoming/outgoing duplex feeder
IF Incoming/outgoing duplex with measurement
BTT Transverse bus-tie
M Measurements
BTL Longitudinal bus-tie
RL Longitudinal riser
RML Longitudinal riser with measurement
12-17.5 kVUnit width (mm) 800
Rated current (A) 630 1250 1600 2000 2500 3150 3600 4000
IF Incoming/outgoing feeder
IF Incoming/outgoing duplex feeder
IF Incoming/outgoing duplex with measurement
BTT Transverse bus-tie
M Measurements
BTL Longitudinal bus-tie
RL Longitudinal riser
RML Longitudinal riser with measurement
12-17.5 kVUnit width (mm) 1000
Rated current (A) 630 1250 1600 2000 2500 3150 3600 4000
IF Incoming/outgoing feeder
IF Incoming/outgoing duplex feeder
IF Incoming/outgoing duplex with measurement
BTT Transverse bus-tie
M Measurements
BTL Longitudinal bus-tie
RL Longitudinal riser
RML Longitudinal riser with measurement
71
4.4
– Depth (mm): 2570– Height (mm): 2400 - (2720 with higher instrument compartment)– Height with gas exhaust duct (mm): 2700
M, BTL, RL and RLM will be available for both A and B busbar system connections.
Unit compartmentsA ApparatusB1 Busbar 1B2 Busbar 2C FeederD InstrumentsE Gas exhaust duct
Hei
ght (
1)
Hei
ght w
ith g
as e
xhau
st d
uct
Width Depth
24 kVUnit width (mm) 800
Rated current (A) 630 1250 1600 2000
IF Incoming/outgoing feeder
BTT Transverse bus-tie
M Measurements
BTL Longitudinal bus-tie
RL Longitudinal riser
RML Longitudinal riser with measurement
24 kVUnit width (mm) 1000
Rated current (A) 630 1250 1600 2000
IF Incoming/outgoing feeder
BTT Transverse bus-tie
M Measurements
BTL Longitudinal bus-tie
RL Longitudinal riser
RML Longitudinal riser with measurement
72
73
5UniGear type ZVC
Page Chap.
Description 74 5.1
Characteristics 76 5.2
Typical units and technical data 78 5.3
74
IF IFIF BT R IF
IF IF IFIF IF IF IF IF
Description
The UniGear range is completed by thecompact contactor unit with fuses. Thisuses vacuum contactors and is designedspecifically for motor, transformer andcapacitor bank switching and protectionfor rated voltages up to 7.2 kV and ratedcurrents up to 400 A. Thanks to the useof fuses as the main means of protection,it can be used in installations with faultcur-rents up to 50 kA.This unit is able to combine maximumaccessibility of all the components withthe most limited dimensions availableon the market today for medium voltageswitchgear. The innovative integrationof the components offers a solution withextremely reduced weight and footprint,allowing efficient use of space in electricalinstallations.The most evident characteristic of this unitis its extreme compactness, just 325 mm.It therefore finds ideal application in installationswith a high number of contactor outgoing feedersor in situations with very limited space available.The use of the contactor unit with fuses is prefera-ble to the use of circuit-breakers when a highnumber of daily operations is required.The interrupters for use in the contactor guaranteean extremely high number of closing and openingoperations under normal load conditions and witha maximum rated short-time withstand currentof 6 kA.The electrical life of the contactor is defined asbeing in category AC3 with 100,000 operations(closing-opening), 400 A interrupted current.
The use of medium voltage protection fusesstrongly limits the fault let-through energy, allowingthe contactor to be used in installations even withhigh fault currents.This characteristic also helps to safeguard thelevels of insulation and increase the electrical lifeof the cables and of the connected machine.For the same reason, the switchgear unit can useearthing switches for the power cables withreduced making capacities compared to the rest ofthe switchgear components, but suitable in anycase for the fault current available on the load sideof the fuses.
75
5.1
Electrical characteristics
Rated voltage
Rated insulation voltage
Rated power frequency withstand voltage
Rated lightning impulse withstand voltage
Rated frequency
Rated short-time withstand current
Peak current
Internal arc withstand current (2)
Main busbar rated current
Branch connection rated current
Maximum performances of the
contactor with fuses
Rated voltage
Motors
Transformers
Capacitors
Maximum load currents of the fuses
(1) Limited by the fuses.(2) The internal arc with-
stand values are guar-anteed in the compart-ments on the supplyside of the fuses (bus-bars and apparatus) bythe structure of theswitchgear and on theload side (feeder) by thelimiting properties of thefuses.
7.2
7.2
20
60
50-60
…50
…125
…40
…50
…4000
400
3.6
3.6
16
40
50-60
…50
…125
…40
…50
…4000
400
kV
kV
kV 1min.
kV
Hz
kA (1)
kA
kA 1s
kA 0.5s
A
A
7.2
4000
4500
2000
3.6
2000
2250
1000
kV
kW
kVA
kVAR
TransformersFuse Maximum
load
FeederRated
voltage3.6kV7.2kV
450A (2x250) 360A450A (2x250) 360A
550A (2x315) 360A550A (2x315) 360A
CapacitorsFuse Maximum
load550A (2x315) 400A550A (2x315) 400A
MotorsFuse Maximum
load
The limiting properties of the fuses also allow cables with reduced cross-sections to be used for the connection between the switchgear and themachines to be protected (reductions between 60 and 80% can be obtained),leading to a considerable reduction in costs.The unit can be coupled directly with the main switchgear, with possibility ofextension on both ends of the switchgear. The same service and mainte-nance procedures are guaranteed as well as full wall-mounting.
StandardsIEC 60470 for the contactor.IEC 60282-1 for the fuses.
76
Characteristics
CompartmentsEach unit consists of three power compartments:apparatus, busbar and feeder.The apparatus and feeder compartments areaccessible from the front by means of a singleaccess door. Door closing is carried out withscrews.Each unit is fitted with an auxiliary compartment,where all the instruments and cabling are housed.The arc-proof switchgear can be fitted with a ductfor evacuation of the gases produced by an arc.All the units are accessible from the front andmaintenance and service operations can thereforealso be carried out with the switchgear wall-mounted.The compartments are segregated from eachother by metallic partitions.
Integration of the componentsThe switchgear is built up around three basicfunctional structures, consisting of macro blocks ofepoxy resin where the components of the switch-gear are incorporated. The top block [A] containsthe whole system of branch connections (towardsthe main busbars and towards the cable terminals)and the fixed contacts (for connection of thecontactor to thebusbar and feeder compartment).The bottom block [B] creates the insulationrequired between the phases at cable terminallevel and that of the fixed contacts of the earthingswitch.The third block [C] is represented by the mainbody of the withdrawable contactor.Segregation between the apparatus, busbar andfeeder compartments is carried out by means of asystem of metallic shutters. These are activatedautomatically during movement of the apparatusfrom the racked-out position to the serviceposition and vice versa. In the case where back-feed of the unit from the cable side is not possible,the bottom segregation shutter of the latter can beeliminated. Even in the unlikely case of back-feed,safety of the operating personnel is guaranteed inany case by the presence of an interlock onlyallowing the unit door to be opened after thepower cable earthing switch has been closed.
The current transformers are normally coupledonto the bottom branch connections of the topmonobloc. They are of the toroidal type and arecompletely insulated from the medium voltagesystem. They can also be replaced from the frontof the switchgear after having removed thecontactor and the shutter segregation system.The unit can also be equipped with toroidaltransformers placed on the power cables in thefeeder compartment.Each unit can be equipped with an earthing switchto earth the cables. The earthing switch is fittedwith short-circuit making capacity up to12.5 kA x 1s and 31.5 kA peak. The apparatus iscontrolled from the front of the switchgear withmanual operation. The position of the earthingswitch can be seen from the front of the switch-gear by means of an indicator.The characteristics of the busbar system, earthingbusbar and gas exhaust duct are the same asthose of the other UniGear units. A maximum oftwo single and three-core cables per phase can beused, depending on the rated voltage and on thecross-section of the cables.
ContactorThe apparatus is dedicated to use in this typicalunit.The epoxy resin monobloc [C] contains theconnections embedded between the top isolatingcontacts, the fuse connections, vacuum interrupt-ers and finally the bottom isolating contacts. Thisstructure also houses the following components:vacuum interrupters, moving equipment, controlelectromagnet, multivoltage feeder and auxiliarycontacts.The contactor can be fitted with an operatingmechanism with electrical or mechanical latching.The contactor can be fitted with a two-pole voltagetransformer complete with protection fuses. Thevoltage transformer must be used for supplyingthe coils of the contactor operating mechanism.The contactor is fitted with medium voltage fusesfor protection of the operated feeders. Coordina-tion between contactor, fuses and protection unitis guaranteed in accordance with the IEC 60470Standards for apparatus in class C.
77
5.2
C
B
A
The monobloc also acts as a fuse-holder frameand is preset for installation of one or two sets ofthree fuses per phase with average type ofdimensions and striker, according to the BS 2692Standard, with a maximum length of 454 mm.The contactor has an automatic opening devicewhen even a single fuse blows.Contrary to the apparatus of the conventionalcompartment, where the connections of theauxiliary circuits of the apparatus with the auxiliaryunit are made by means of a plug-socket systemwith manual coupling, the contactordedicated to this unit uses an automatic couplingsystem. This is activated automatically duringmovement of the apparatus from the racked-outposition to the service position and vice versa.
78
1
2
3
A
B
C
D
E
Off
M~3M~3
M~3M~3
M~3M~3
M~3M~3
1 2
3
A
B C D E
Typical units and technical data
Single-line diagram of the typical units
Key to components
Contactor with electrical latching
Contactor with mechanical latching.
Two-pole voltage transformer for supplying the con-trol circuits
Typical motor start-ups
Direct
Reverse direction
Reactor
Autotransformer
Star-delta
Standard components
Accessories
Alternative solutions
79
5.3
B
C
D
A
E
C
A
E
D
The contactors used to operate each motor areinterlocked together by means of electromechanicaldevices.These operate by means of locking magnets withactive logics and therefore auxiliary voltage cut-offmakes the lock operative. The starting and switch-ing sequences can be fully automated by means ofthe REF542plus unit.The unit software makes the control logics and itsgreat flexibility allows it to be adapted efficaciouslyto the characteristics of the machine to be operat-ed. The interlocks between the contactors dedicat-ed to operation of the machine can also be man-aged safely by the REF542plus unit.
The compact contactor units with fuses in theUniGear range have been specifically studied tooffer the best performances with direct motorstarting, as this is the type most widely used.The switchgear can, however, also be used forcomplex starting, which requires the use of severalcontactor units.The connections between the various units usedduring the starting and running stage, such asbetween the machines (motor, reactor, autotrans-former), are made using cables.The phase inversions are carried out directly onthe output of the switchgear by means of thepower cables. The units which make the starcentre of the machines must be positioned at theend of the switchgear.
... 7.2 kV - ... 50 kADepth (mm) 1125
Height (mm) 2200/2595 (1)
Height with gas exhaust duct (mm) 2675
Width (mm) 325
Rated current (A) 200 400
IF Incoming/outgoing
(1) The height of the unit isa function of the heightof the instrument com-partment, available inthe 675 and 1070 mmversions.
Width
Depth
Hei
ght (
1)
Hei
ght w
ith g
as e
xhau
st d
uct
Unit compartmentsA ApparatusB Main busbarsC FeederD InstrumentsE Gas exhaust duct
80
81
6Marine Applications
Page Chap.
Description 82 6.1
Characteristics 84 6.2
Typical units and technical data 86 6.3
82
In the recent past, the electrical network of marineplants was manufactured with low voltage compo-nents. The increase in power and short-circuitcurrent has obliged shipyards to move to mediumvoltage.In the beginning 3.6kV was used in most cases,but the current requirements are 7.2 and 12kV.The plants are rapidly reaching the limits (50kA)even at these voltages and the long-term vision isfor 12kV only.The use of 13.8kV could be taken into considera-tion (few builders have already used this voltage).The switchgear suitable for marine applications istherefore 7.2-12kV switchgear (with the option for17.5kV), with the need for many dedicated fea-tures and some special typical units.The temperature range, vibrations and variableinclination are particularly severe conditionsaffecting the functional efficiency of on-boardcomponents such as the switchgear.Other conditions (e.g. high humidity and salineconcentration) only affect off-board equipment andtherefore not the switchgear.ABB is the leading manufacturer of air-insulatedswitchgear for marine applications, installed by allmain shipyards (Brazil, China, Denmark, Finland,France, Germany, Japan, Korea, Italy, Norway,Singapore, Spain, UK and USA).
Over 5,000 ABB panels are in service in the worldon board all kind of ships. ABB delivers about 500units per year.
Registers and end-customers (shipyards or shipowners) require switchgear manufactured tocomply with Shipping Register test requirementsfor on-board apparatus.For this purpose, tests have been performed incompliance with the main Shipping Registerregulations; DNV, LR, RINA, BV, GL and ABSregulations.
Description
83
6.1
The Marine Market can be divided into fourdifferent segments:– Passenger vessels (cruise ships and ferries).– Industrial vessels (shuttle tankers, drill ships, oil
carriers, cargo vessels, etc.).– Rigs (drill and oil rigs).– Navy (Military navy).
In this type of plants where there is high humidityand saline concentration as well as a variabletemperature range, the vibrations and the variabletrim are particularly severe conditions affecting thefunctional efficiency of ships, tankers, containerships, etc.Moreover, in order to guarantee the necessarycomfort and facilities, high electrical powergeneration plants and control systems must beconcentrated in significantly reduced overalldimensions.UniGear, coupled with double level and/or ZVC,offers a wide range of apparatus and control unitsto satisfy marine installation requirements.
ApplicationsUniGear apparatus provides ideal technicalsolutions for marine applications:– Arc-proof construction, mechanical safety
interlocks, automatic segregation shutters andapparatus control with the door closed guaran-tee personnel safety during installation, mainte-nance and service;
– High degree of protection (up to IP43) on theexternal enclosure;
– Metallic partitions between each compartmentand earthing of all components accessible topersonnel: apparatus, shutters, doors and thewhole switchgear frame;
– High fire resistance thanks to scarce use ofplastic and resins: the auxiliary equipment andwiring are highly self-extinguishing.
Ambient conditions for classification of on-board apparatus
– Ambient temperature from 0 °C to + 45 °C– Inclination up to 25° permanent
Vibration in the frequency range of 2 … 100Hz at the following motion width
– 1mm amplitude in the frequency range of 2…13.2Hz– 0.7g acceleration amplitude in the frequency range of 13.2…100Hz
Electrical characteristics
kV
kV
kV 1 m
kV
Hz
kA 3s
kA
kA 1s
kA 0.5s
A
A
A
12
12
28
75
50-60
...50
...125
…40
...50
1250...4000
630...3150
3600...4000
7.2
7.2
20
60
50-60
...50
...125
…40
...50
1250...4000
630...3150
3600...4000
Rated voltage
Rated insulation voltage
Rated power frequency withstand voltage
Rated lightning impulse withstand voltage
Rated frequency
Rated short-time withstand current
Peak current
Internal arc withstand current
Main busbars rated current
Branch connection rated current
Branch connection rated current with forced ventilation
84
1 Gas exhaust duct2 Flaps3 Top chimneysArc venting system
The features required, which are not part of thestandard design, are described below.
Degree of ProtectionThe standard external degree of protection ofmarine switchgear is IP42 or IP43.
Wiring ductEvery switchgear unit is equipped with the top-mounted interconnection wiring duct and the totalswitchgear height must be 2500 mm (2530 mmwith gas duct and top chimneys). The duct is fixedon the top of the auxiliary compartment.
Gas ductUniGear is always in the arc-proof version andtherefore equipped with the gas duct.The duct is fixed on the top of the auxiliarycompartment. In marine plants, the exhaust gasescannot normally be evacuated out of the room andtherefore the gas duct must always be closed onboth the end-sides and equipped with top chim-neys.If there are cases where it is possible to evacuatehot gases out of the room, the standard gas ductcan be supplied.
CablesSingle Level UniGearSingle level IF and IFM units will mainly be in thedeeper version (1840-1890 mm). This design willallow the following targets to be achieved:– bottom and top cable entry;
Characteristics
– appropriate cable terminal distance (minimumrequirements):- 700mm in case of bottom entry;- 1000mm in case of top entry.
Standard depth IF units (1340-1390 mm) are alsoused as an alternative in case of problems withspace.This feeder version will only allow bottom cableentry and a cable terminal distance in the range of440…535 mm, depending on the rated current.
UniGear ZVCBottom cable entry units are equipped with twocables per phase. The terminal distance from thefloor is 630 mm. The unit is 1124 mm deeper.Top cable entry units are equipped with two cablesper phase. The terminal distance from the ceilingis 900 mm. The unit is 1654 mm deeper.
Double Level UniGearDouble level units will be in the standard depthdesign. All the described recommendations forsingle level units must be applied to double levelunits.The cable terminal distance of IF units is 600 mmfor all the following configurations:– Bottom entry– Top entry– Bottom and top entry.
DoorsAs standard, all the doors (auxiliary, apparatusand feeder compartments) are equipped with anappropriate stop to fix them in the open position.
85
6.2
Compound configuration with single level, double level and ZVC
Thermo-graphic inspectionThermo-graphic inspection is normally required onpower cables terminations and sometimes on mainbusbar systems.Customers are normally much more sensitive tothe former, because cable termination faultsrepresent a considerable part of all the faults inswitchgear, whereas faults in main busbar systemsare quite rare.Thermo-graphic inspection and supervision can bedone in two ways:
– Temporary inspection by means of an IR camerathrough an appropriate inspection window.
– Continuous supervision by means of IR sensorslocated inside the switchgear.
The first system (temporary inspection) requires anIR camera and an inspection window for eachcompartment to be supervised.The second system (continuous supervision)requires the SensyCal IR system. This is a non-touch temperature monitoring system based on IRtemperature probes connected to a central unit (12sensors can be plugged in to each central unit).Due to the switchgear design constraints, the mainbusbar thermo-graphic inspection can only becarried out using the SensyCal IR system, whereasthe power cables can be supervised with both theSensyCal IR and the IR camera.
Outgoingfeeders withcircuit-breakers
Metering unit
Outgoingfeeder
Incomingfeeder
Slimcontactorfeeder
Slimcontactorfeeder
Incomingfeeder
Bus tie Bus riser Metering unit
Outgoingfeeder
With regard to Double Level UniGear, we can pointout that due to the switchgear design constraints,both the main busbar and the power cablesthermo-graphic inspection can only be carried outusing the SensyCal IR system.
Outgoingfeeders withcircuit-breakers
86
The units required, which are not part of thestandard design, are described below.
Earthing transformer unitsFrom the electrical point of view, marine plants arebased on isolated networks (isolated neutralpoint).The main consequences regard the following:– the network can be operated with single-phase
earth fault;– earth fault detection is very difficult, due to the
very low earth fault current.In order to increase this and therefore allowreleases to operate on single-phase earth faults,two solutions can be used:– connecting the secondary winding of the
generator to ground by means of a resistor;– installing an earthing transformer in the network.
For this reason, the UniGear range must beenriched with two addition typical units:– ME: Busbar metering unit with earthing trans-
former feeder;– RE: Rise with earthing transformer feeder.
In the case of switchgear with a single busbarsection, ME can be used for this purpose; in thecase of switchgear equipped with two busbarsections, both ME and RE units must be used, inorder to cover all the schemes.
Additional features of M and R unitsOut of choice, M and R units should be equippedwith fixed VTs instead of withdrawable VTs withfuses.In this configuration the so-called “VT compart-ment” will be used as an additional auxiliarycompartment. It must be fully segregated from thepower compartments with metallic partitions anddesigned as an auxiliary compartment withrespect to the safety rules.The inside rear and side walls of the compartmentmust be fitted with the grid plate for fixing theauxiliary equipment. This will be equipped with therelevant left-hand side duct for wiring entry fromthe bottom and exit to the top-mounted auxiliarycompartment.
Typical units and technical data
M – Metering with earthingtransformer.
RLM – Bus Riser withmetering and earthingtransformer.
87
6.3
– Depth (mm): refer to the above table.– Height (mm): 2530 mm (gas duct with top chimneys included).– (1): Bottom and top cable entry.– (2): Bottom cable entry.– (3): Up to 50kA with V-Contact
Unit width/depth (mm) 650 / 1840
Rated current (A) 630 1250 1600 2000 2500
IF Incoming/outgoing feeder (1) (3)
IFM Incoming/outgoing with measurement (1) (3)
7.2-12 kV – 40-50 kA
Unit width/depth (mm) 650 / 1340
Rated current (A) 630 1250 1600 2000 2500
IF Incoming/outgoing feeder (1) (3)
BT Bus-tie
R Riser
RE Riser with earthing transformer
RM Riser with measurements
M Measurement
ME Measurement with earthing transformer
7.2-12 kV – 31.5 kA
Unit width (mm) 800 1000
Unit depth (mm) 1840 1890 1840 1890
Rated current (A) 630 1250 1600 2000 2500 3150 4000 630 1250 1600 2000 2500 3150 4000
IF Incoming/outgoing feeder (1)
IFM Incoming/outgoingwith measurement (1)
Unit width (mm) 800 1000
Unit depth (mm) 1840 1890 1840 1390
Rated current (A) 630 1250 1600 2000 2500 3150 4000 630 1250 1600 2000 2500 3150 4000
IF Incoming/outgoing feeder (1)
BT Bus-tie
R Riser
RE Riser with earthing transformer
RM Riser with measurements
M Measurement
ME Measurement with earthingtransformer
88
Notes
1
ABB Power Technologies S.p.A.Unità Operativa SaceVia Friuli, 4I-24044 DalmineTel: +39 035 395111Fax: +39 035 395874E-mail: [email protected]://www.abb.com
ABB s.r.o.Org. unit EJFVidenská 117, 619 00 BrnoCzech RepublicTel: +420 5 4715 2413, 1111Fax: +420 5 4715 2190E-mail: [email protected]://www.abb.com
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