UniGear type ZS1Medium voltage, arc-proof, air-insulated,metal-clad switchgear

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47

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UniGear type ZS1

UniGear Double Level

UniGear type ZVC

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1UniGear type ZS1

Pag. Cap.

Description 4 1.1

Air-insulated 6 1.2

Metal-clad 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 18 1.8

Vacuum contactor 20 1.9

Service trucks 22 1.10

Switch-disconnector 24 1.11

Instrument transformers 26 1.12

Measurement sensors 28 1.13

Protection and control systems 30 1.14

Automatic transfer systems 32 1.15

Typical units and technical data 34 1.16

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UniGear

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Characteristics• Metal-clad, air-insulated

switchboard.• Suitable for medium voltage

distribution.• Guaranteed arc-proof units.• Factory-tested for indoor

installations.• Tested in accordance with the

main international Standards.• Wide range of functional units

available for all installationsolutions.

• Compartments segregated bymeans of metallic 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

�

Applications

Utilities and Power Plants• Power generation stations• Transformer stations• Switching stations• Main and auxiliary switchboards.

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 switchboard areguaranteed arc proof in accordance with the IEC60298 Standards, appendix AA, class A accessi-bility, criteria 1 to 6.All the start-up, maintenance and service opera-tions can be carried out from the front. Theswitchgear and the earthing switches are oper-ated from the front with the door closed. Theswitchboard can be wall-mounted.The range of apparatus for the UniGear switch-board 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 singleswitchboard-user interface possible, with thesame service and maintenance procedure andoperations. The fixed version switch-disconnectorunits complete the range of apparatus.The switchboard can be fitted with conventional(transformers and relays) or innovative (sensorsand multi-purpose unit) measurement andprotection components.Apart from the traditional functional units, theUniGear switchboard is fitted with double-levelsolutions and compact units equipped withcontactors with fuses. The use of these unitsallows extremely efficient use of space.

StandardsThe switchboard and main apparatus contained init comply with the following Standards:• IEC 60694 for general purpose.• IEC 60298 for the switchboard.• 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 of produc-ers, distributors and users of electric power.The medium voltage switchboard is one of themost important links in the electric distributionchain and ABB has developed the UniGearswitchboard with the aim of satisfying all require-ments.UniGear is the combination of consolidatedsolutions and innovative components, both ofwhich are the fruit of ABB technology.UniGear is a medium voltage metal-clad switch-board with 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 switchboards are used by ourcustomers for efficient use of electric power.

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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

24

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

12

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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Earthing switchEach 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.Control of the apparatus is from the front of theswitchboard with either manual or motor-operatedoperation.The position of the earthing switch can be seenfrom the front of the switchboard by means of anindicator.

Earthing busbarThe earthing busbar is made of electrolytic copper.It runs longitudinally all round of the switchboard,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 respec-tively. They are single-pole type and are made ofepoxy resin.The shutters are metallic and are activatedautomatically during movement of the apparatusfrom the racked-out position to the service positionand 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 switchboard can be wall-mounted in thestation because the cables are easily accessiblefrom the front.

Metal-clad

CompartmentsEach 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.The arc-proof switchgear is normally provided witha duct [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 switchboard wall-mounted.The compartments are segregated from eachother by metallic partitions.

Main busbarsThe 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 flatbusbars; for currents between 3150 A and 4000 A,a special copper section is used.The busbars are normally covered with insulatingmaterial. There is a single busbar compartmentalong the whole length of the switchboard and thiscan be fitted with segregations for dividing eachunit into compartments.

Branch connectionsThe 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.

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1.3

A

C

D

E

B

Gas exhaust ductThe gas exhaust duct is positionedabove the switchboard and runsalong its whole length.Each power compartment is fittedwith a flap positioned on the top of it.The pressure generated by the faultmakes it open, allowing the gas topass into the duct.Evacuation from the room of the hotgases and incandescent particlesproduced by the internal arc mustnormally be carried out. The UniGearswitchboard is fitted with a completerange of solutions to deal with allrequirements, either in the casewhere evacuation is possible directlyat the end of the switchboard, orwhen solutions from the front or rearare requested.Some installations, such as marineones, do not allow conveyance of thegases to the outside of the room andtherefore dedicated solutions havebeen realised to guarantee person-nel safety and conformity with theStandards, such as expansionchambers, absorbent filters andlongitudinal evacuation chimneys.

Busbar applicationsEach switchgear unit can be fittedwith an accessory busbar applica-tion:• current or voltage transformers for

busbar measurements• busbar system earthing switch• top entry duct to make interconnec-

tions between different switch-boards.

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Safe

The UniGear switchboard 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. Theirpresence guarantees the highest level of reliabilityeven in the case of an accidental error and allowswhat ABB defines as an “error-free” system ofinterlocks.

KeysThe use of key interlocks is very important inrealising the interlocking logics between units ofthe same switchboard, or of other medium, lowand high voltage switchboards. The logics arerealised by means of distributors or by ringing thekeys.The apparatus truck [6] can be locked in theracked-out position and the relevant lock key canonly be removed with the apparatus in thisposition.The earthing switch closing [7] andopening [8] operations can be locked by means ofkeys. The latter can only be removed with theearthing switch in an opposed position to the lockto be made. 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. Thepadlock can also be applied to the earthing switchof busbar applications.The metallic segregation shutters [15] can belocked by means of two independent padlocks inboth the open and closed positions.The switchboard is preset for using padlocks witha 4 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 Open apparatus compartment door

5 A Feeder compartment door opening Open earthing switch

B Earthing switch opening Open feeder compartment door

Lock Condition

1 A Apparatus racking-in/out Closed apparatus

B Apparatus closing Undefined truck position

2 A Apparatus racking-in Unplugged apparatus multi-contact plug

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 Closed earthing switch

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 switch 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 closed position when the apparatus is removed from thecompartment. The operator cannot open the shutters manually. The shutters can only beoperated by the apparatus truck or the service trucks.

21 Apparatus-switchboard unit The apparatus multi-contact plug and relative switchboard unit socket are equippedcompatibility matrix with a mechanical matrix, that disables apparatus racking-in into a switchboard unit with an

inappropriate rated current.

22 Circuit beaker mechanical The apparatus compartment is equipped with a mechanical device, that enables circuitoperating 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 circuitbreakers in the service and racked-out position.

Keys

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Type-tested

The UniGear switchboard hasundergone all the tests required bythe international (IEC) Standardsand local Standards (for example,the Chinese 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 marineinstallations.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.

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 switchboard 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 the ratedcurrent value of the switchgear unit and showsthat the temperature does not become excessiveinside of it. During the test, both the switchboardand the apparatus it may be fitted with arechecked (circuit-breakers, contactors and switch-disconnectors). Apparatus subject to testing in freeair is able to withstand higher rated currents thanthat inserted in a switchgear unit, therefore therated current of the apparatus depends on thecharacteristics of the switchboard and on therelevant ventilation system (natural or forced).

• DielectricThese tests check that the switchboard hassufficient capability to withstand the lightningimpulse and the power frequency voltage. Thepower frequency withstand voltage test is carriedout as a type test, but is also routine on everyswitchgear unit manufactured.

Arc withstand test. 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 normallylower than the rated one.Apart from this, each switchgear unit is subjectedto the routine tests in the factory before its delivery.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 impendence

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 registers:• High ambient temperatures.• 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.

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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 switchboardcan be 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. Generalexperience in the electro-technical sector showsthat mechanical faults are one of the most com-mon causes of a fault in an installation. Theswitchboard and apparatus it contains are testedby 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 theshipping registers:

• High ambient temperaturesThe service conditions of the electri-cal apparatus in shipping installa-tions are generally more severe thanthose in normal land applications.The temperature is certainly one ofthese factors and for this reason theshipping register regulations requirethe switchboard to be able to operateat higher ambient temperatures(45°C, but even higher) than thoseforeseen in the IEC Standards(40°C).

• InclinationThe test is carried out by inclining the switchboardfor a defined time up to 25° alternatively on all foursides and operating the apparatus (circuit-breaker,contactor and earthing switch). The test prove thatthe switchgear is able to resist these extremeservice conditions and that all the apparatus itcontains can be operated without any problemsand without being damaged.

• VibrationThe reliability and sturdiness of the UniGearswitchboard 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 theswitchboard to work in environments stronglyaffected by vibrations, such as those caused bythe operating motors onboard large cruise shipsor on the drilling plants of oil rigs. The switchboardhas undergone the vibration test with a frequencyband from 2 to 100 Hz and with the followingmotion with:– 1 mm amplitude in the frequency range between

2 and 13.2 Hz.– 0.7 g acceleration amplitude in the frequency

range between 13.2 and 100 Hz.

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When developing modern medium voltageswitchgear, personnel safety must necessarilytake first place and this is why the UniGearswitchboard has been designed and tested towithstand an internal arc due to a short-circuitcurrent of the same level as the maximum short-time withstand level.The tests show that the metal housing of theUniGear switchboard is able to protect personneloperating near the switchboard in the case of afault which evolves as far as striking an internalarc.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 of

the 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 switchboard

during maintenance operations.The characteristics of the UniGear switchboardnotably reduce the incidence of these causes ingeneration 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 switchboard

structure.• Melting, decomposition and vaporation 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 switchboard. Moreover that no holes areproduced in the external freely accessible parts ofthe housing and finally, that all the connections tothe earthing circuit remain efficacious, guarantee-ing the safety of personnel who may access to theswitchboard after the fault.The IEC 60298 Standard describes the methodsto be used for carrying out the test and the criteriawhich the switchboard must conform to in appen-dix AA. The UniGear switchboard fully conforms toall the parameters indicated in the Standard forapparatus of class A type accessibility and to allthe criteria indicated:1 The doors of the switchboard must remain

closed and no opening of the cover panelsmust occur.

2 Any part of the switchboard which may behazardous for personnel must not be ejected.

3 No holes must appear in the external housingof the switchboard in any parts accessible topersonnel.

4 The vertically arranged fabric indicators placedoutside the switchboard must not get burnt.

5 The horizontally arranged fabric indicatorsplaced outside the switchboard must not getburnt.

6 All the switchboard earthing connections mustremain effective.

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.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.The UniGear switchboard is fitted with a completerange of solutions to deal with all requirements,when evacuation is possible inside the room, butalso when this is not compatible with the plantcharacteristics, as in the case of shipping installa-tions.

Arc proof

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1.6

ITHThe sensors consist of microswitches positionedon the top of the switchboard near the gas exhaustflaps of the three power compartments (apparatus,busbars and feeder). The shock wave makes theflats open and operate the microswitches con-nected 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 switchboard in service.

TVOCThis system consists of an electronic monitoringdevice located in the auxiliary compartment whichthe optic sensors are subject to. These are distrib-uted in the various power compartments and areconnected to the device by means of optic fibres.When a certain established light level is ex-ceeded, the device opens the circuit-breakers. Toprevent the system from intervening due to lightoccasionally generated by external phenomena(flash of a camera, reflections of external lights,etc.), the current transformers can also be con-nected. The protection module only sends theopening command to the circuit-breaker if itreceives the light and short-circuit current signalsimultaneously.

REAThis device is a true protection relay, incorporatingthe active protection functions against fault due toan internal arc, protections against short-circuitovercurrent and the supervisory function of thecircuit-breaker. This system uses a network of opticfibres suitably located around the switchboard(radial or ring) and connection to the currenttransformers to detect the fault and operate thecircuit-breaker.

The UniGear switchboard offers complete passivetype protection against the effects of a fault due toan internal arc by means of its structure for a timeof 1s 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 in

less than 100ms.• Limitation of the consequences of the fault on

the 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 and carryout selective opening of the circuit-breakers.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 tothe latter.

Steel

Copper

Cables

Arc duration anddamage caused

16

The UniGear switchboard can befitted with the widest range ofapparatus available on the markettoday and of these the vacuumcircuit-breaker now occupies aposition of prime importance in allsectors of primary distribution.Vacuum circuit-breakers cover thewhole range of switchboard param-eters and therefore of the wholerange of applications.Dozens of years of experiencegained in developing and usingvacuum interrupters are todayreflected in the range of ABB circuit-breakers, which stand out for their

exceptional electrical and mechanical characteris-tics, extremely long and maintenance-free life,compactness and the use of highly innovativeconstruction techniques.ABB develops and produces a complete range ofinterrupters for use in circuit-breakers and contac-tors and for all medium voltage applications.

VD4The VD4 medium voltage circuit-breaker interrupt-ers use the vacuum to extinguish the electric arcand as insulating medium.Thanks to the unequalled properties of vacuumand the breaking technique used, current interrup-tion takes place without arc chopping and withoutgeneration of overvoltages. There is no restrikingphenomenon after interruption and restoration ofthe dielectric properties following interruption isextremely rapid.There are circuit-breakers for every field ofelectrical power distribution. They can be particu-larly recommended for the use on arc furnaces,overhead lines with frequent auto-reclosing, rapidchangeover systems and in extremely pollutedplants as well as under difficult environmentalconditions.

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 guaran-tee even distribution of the arc roots over thewhole surface of the contacts, allowing topperformances at all current values.The structure of the vacuum interrupters is rela-tively simple. The external housing consists of aceramic insulator closed at the ends by stainlesssteel covers. The heart of the interrupter consists ofthe main contacts. Use of a multi-layer structureand appropriate metals (chrome copper alloy,copper and steel) guarantees high performancesunder all service and fault conditions, longmechanical life, and excellent electrical andthermal conductivity. The multi-layer structure ismade by means of a welding process in anatmosphere with a very high vacuum.The interrupter does not therefore contain anyionisable material. On detachment of the contactsthere is, in any case, generation of an electric arcwhich consists exclusively of the melting andvaporisation of the materials of the contacts. Theelectric arc remains supported by the externalenergy until the current is annulled.Supervision of the vacuum level is not necessarysince the circuit-breaker poles are sealed-for-lifepressure systems and are maintenance-free.

Operating mechanismThe VD4 circuit-breaker is fitted with a mechanicalstored energy type operating mechanism. Releaseis free and therefore allows opening and closingoperations 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 anantipumping 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.

Vacuum circuit-breakers

17

1.7

StandardsIEC 62271-100 for the circuit-breaker.

VM1The conventional mechanical storedenergy type of operating mechanismof the VD4 circuit-breakers can bereplaced with an operating mecha-nism with magnetic actuator, therebygiving rise to the VM1 series ofcircuit-breakers.All the characteristics of the circuit-breakers described in this chapterremain unchanged except for theoperating mechanism.

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. Alternatively, thetruck can be fitted with a plug for earthing bymeans of a dedicated circuit as far as the mainearthing busbar of the switchboard.The vacuum circuit-breaker truck can be motor-operated. The racking-out and racking-in opera-tions can be carried out by means of electricalcontrols, either locally by the operator or by aremote system.

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

mechanism springs.• Override selector of the undervoltage release

(optional).

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(release, operation, energy charging andwatchdog) are carried out from the integratedelectronic controller. The circuit-breaker is fittedwith a multivoltage 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-Oreclosing sequence.

• Position sensors. The position of the circuit-breaker contacts is detected by means ofelectronic proximity sensors.

18

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 operatesoptimally in switching low currents, the latter actseffectively during operation on higher currentvalues.The autopuffer technique allows to use smallergas quantity than those required by circuit-breakers based on other techniques. For the samereason, the gas pressure is also considerablyreduced. The autopuffer technique guarantee theinsulating withstand voltage and the breakingcapacity up to 30% of the rated one even with zerorelative pressure.The whole range of HD4 circuit-breakers uses thesame gas pressure for all rated voltage levels (12-17.5-24 kV).Supervision of the SF6 gas pressure level is notnecessary, 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 followingtransportation, shocks or incorrect use.

Operating mechanismThe HD4 circuit-breaker is fitted with a mechanicalstored energy operating mechanism. Release isfree and therefore allows opening and closingoperations independent of the operator.The operating mechanism spring system can berecharged either manually or by means of ageared motor.The operating mechanism is of the same type forthe whole 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).The circuit-breakers are always fitted with anantipumping 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.

The single and double-level switch-boards can be fitted either withvacuum circuit-breakers or with SF6circuit-breakers.The ABB vacuum and gas series ofcircuit-breakers are mechanicallyinterchangeable and the sameswitchgear unit can therefore takeeither type of apparatus.Only ABB can offer apparatusbelonging to the two techniques forthe whole range of applications,voltage levels (12-17.5-24 kV), ratedcurrent (630...4000 A) and breakingcapacity (16...50 kA), giving theopportunity of selecting those mostsuited to the installation characteris-tics and to the feeders to be switchedand protected.

The long and proven experience of ABB showsthat the two types of circuit-breakers are equallyvalid and complementary and therefore allowoptimised selection for their use.

HD4The HD4 medium voltage circuit-breakers usesulphur hexafluoride gas (SF6) to extinguish theelectric arc and as insulating medium.Thanks to the excellent properties of SF6 gas,interruption of the currents takes place without arcchopping and without any generation ofovervoltages. There is no restriking phenomenonafter interruption and the dielectric propertiesfollowing interruption are recovered extremelyrapidly.There are circuit-breakers for all electric powerdistribution applications. They can be particularlyrecommended for the use on capacitor banks,compensation reactances, transformers insulatedin oil and in installations where components whichare 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.

Gas circuit-breaker

19

1.8

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. Alternatively, thetruck can be fitted with a plug device for earthingby means of a dedicated circuit as far as the mainearthing busbar of the switchboard.

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.• Manual charging device of the operating

mechanism springs.• Override selector of the undervoltage release

(optional).• LED gas pressure indicator (optional).

StandardsIEC 62271-100 for circuit-breaker.IEC 60376 for the SF6 gas.

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.

HD4-HXAThe range of HD4circuit-breakers isenriched by the HXAversion.This series of circuit-breakers keeps all thecharacteristics de-scribed in this chapter,but stands out for itsability to switch loadswith strong unidirec-tional components.For breaking capacitiesof 40 kA or lower, theyare able to switch loadswith unidirectionalcomponents IDC = 100%.At 50 kA the unidirec-tional componentpercentage IDC isreduced to 50%.

20

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 the V-Contactcontactors is defined as being incategory AC3 with 100,000 opera-tions (closing-opening), 400 Ainterrupted current.The contactors consist of a monobloc

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 theshunt opening release for instantaneous service,the opening 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 fuses per phase with averagedimensions and type of striker, accordingto the following Standards:• DIN 43625.• BS 2692.The following fuses can be applied:• DIN type with a lenght of 192, 292 and 442 mm• BS type with a lenght of 235, 305, 410, 454 and

553 mm.The fuse-holder frames are fitted with a device forautomatic opening when even a single fuse blows.This same device does not allow contactor closingwhen even a single fuse 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-polesvoltage transformer complete with the relevantprotection fuses. The voltage transformer is usedto supply the coils of the contactor operatingmechanism. Apart from power supply of thecontactor, it can also supply other components ofthe switchgear unit (lamps, signalling devices,auxiliary relays, etc.) up to a maximum power of50 VA.

of resin containing 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. Thecontactor remains in the closed position as longas the electromagnet remains energised andopens automatically when the auxiliary voltage iscut off.

Vacuum contactor

21

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 switchboard and onthe load side (feeder)by the limiting propertiesof the 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 Maximumcurrent 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

���� �� ���� ���� ���� ���� ���� ����

���� �� ���� ���� ���� ���� ���� ���

�� �� ���� ���� ���� ���� ���� ����

22

Service trucks

The UniGear range is equipped with all theservice trucks needed to complete the switch-board and required for service operations andduring maintenance work.The trucks are divided into four different types:• Earthing without making capacity.• Earthing with making capacity.• Test cables.• 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 switchboard 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 switchboard structure.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 capacityThese 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 by means ofthe 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 switchboard (circuit-breaker orcontactor) and its replacement with the truck. Theunits preset for use of the earthing trucks areprovided with a key lock which, when activated,prevents its racking-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 capacityThese 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 switchboard (circuit-breaker orcontactor) and its replacement with the truck. Theunits preset for use of the earthing trucks areprovided with a key lock which, when activated,prevents their racking-in.This truck is available in two versions:• Earthing of the main busbar system.• Earthing of the power cables.

23

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 cables test truckThese trucks allow the insulation tests on thepower cables to be carried out without accessingthe feeder compartment or disconnecting thecables from the switchboard.The use of these trucks foresees removal of theapparatus from the switchboard (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.

Isolating truckThe 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 environ-ment. In the incoming/outgoing feeder units itconnects the main busbar system to the powercables, whereas in the bus-tie, the two sides of thebusbar system.This truck has its application in UniGear switch-boards for making incoming/outgoing feederswithout a circuit-breaker in radial networks, formaking cable connections between two switch-boards placed in front of each other, in makinginterconnection units and in creating the bus-tie-riser 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 trucks arefitted with a key lock which, when activated,prevents its being racked-in.

Main busbar system earthingtruck, without making capacity.

Power cables earthing truck,without making capacity.

Cables test truck.

Main busbar system earthingtruck, with making capacity.

Power cables earthing truck,with making capacity.

Isolating truck.

24

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-insulatedapparatus consisting of a fixedsupport to which the supportinginsulators are applied (top andbottom), the system of contacts (fixedand moving) and latching pliers (ofthe fuses or of the insulating 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 solutionsmeans the main contacts are notstressed and therefore keep the

electrical characteristics of the apparatus un-changed.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 trippingand uses fuses in accordance with DIN 43625Standards. The ABB range of fuses for transformerprotection is called CEF. Eachunit is fitted with an earthing switch with makingcapacity for earthing the cables.

Switch-disconnector control, like that of theearthing switch, comes from the front of theswitchboard by means of manual operation.The position of both apparatus can be seendirectly from the front of the switchboard throughan 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 switchboard inservice.

The switch-disconnector, earthing switch andaccess door to the feeder compartment areinterlocked with each other to guarantee maxi-mum safety for the personnel and correct opera-tion.

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 switchboard wall-mounted.

StandardsIEC 60265-1 for the switch-disconnector.IEC 60282-1 for the fuses.

25

1.11

20

50

630

…20

25

63

630

…25

25

63

630

…25

25

63

630

…25

kA 1 s

kA

A

kA 1 s

kV 25 40 50 63 80 100 125 160 200 250 315 400 500 630 800 1000 1250 1600

3 10 16 25 25 40 40 63 63 100 100 100 1005 6 10 16 16 25 25 40 40 63 63 100 100 100 1006 6 6 10 10 16 16 25 25 25 40 40 63 63 100 10010 6 6 10 10 16 16 25 25 25 40 40 63 63 100 10012 6 6 6 10 10 16 16 25 25 40 40 40 63 63 100 100 10015 6 6 6 10 10 16 16 25 25 25 40 40 40 63 63 100 10017 6 6 6 6 6 10 16 16 25 25 25 40 40 63 63 63 100 10020 6 6 6 6 6 10 16 16 16 25 25 40 40 40 63 6324 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) bythe structure of the switchboard andon the load side (feeder) by the limitingproperties 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)

Short-time withstand current

Peak current

Maximum rated current of the switch-disconnector

Internal arc withstand current

NAL switch-disconnector unit

NALF switch-disconnector unit with fuses

Selection table of the fuses for protection transformers

Rated power of the transformer (kVA)

Rated normal current of the fuse (A)

Electrical characteristics

24

24

50

125

50-60

17.5

17.5

38

95

50-60

12

12

28

75

50-60

7.2

7.2

20

60

50-60

kV

kV

kV 1 m

kV

Hz

…25

…63

63

…25

-

…50

…125

125

…40

…50

…50

…125

125

…40

…50

kA (1)

kA

A

kA 1 s

kA 0.5 s

…40

…100

63

…40

-

26

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 versions up to2500A, whereas they are of the toroidal type in the range ofcurrents 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 the phasecurrents of the switchgear unit. Mounting on the supply side ofthe apparatus compartment is also possible (busbar applica-tions) for measuring the busbar currents or for realising particu-lar protection schemes. The ABB range of current transformersis called TPU.

Toroidal current transformersThe toroidal transformers are of the type insulated in resin andare used to supply measurement and protection devices. Thesetransformers can either be with a closed or openable core.They can be used both for measuring phase currents or fordetecting the earth fault current. They conform with the IEC60044-1 Standards.

TPU 1250 A.

TPU 2500 A.

Toroidal currenttransformer. TPU 3150 A.

27

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. Anyintervention of one of the fuses is signalled by means of specialcontacts.The withdrawable trucks also allow replacement of the fuseswith the switchboard 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 (busbar applica-tions).The ABB range of voltage transformers is called UMZ.

One-pole UMZ.

Two-poles UMZ

One-pole with fuse holder UMZ.VTs truck with fuses.

28

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

measurement and protection instrument is madewith shielded 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 switchboard modifi-

cations 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 switchboard can be fitted withKEVCD type 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.

29

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 cross-section. 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 thesignal.

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 switchboard 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.

30

Protection and control systems

Thanks to the use of the REF542plus unit, eachmedium voltage UniGear panel becomes anintegrated and independent unit able to carry outall the required functions.• Integration of all the functions in a single

instrument: protection, measurement, controls,signalling, interlocking, automation and commu-nication.

• Single interface between switchboard andoperator for all the installation panels: feeder,transformer, motor, generator, power correctionbanks, bus-tie and measurements units.

• Single type of spares parts and accessories: asingle hardware unit.

• Reduced maintenance: drastic reduction inpreventive maintenance, great limitation of thefaults caused by tampering and errors.

• Easy modification and upgrading of the func-tions: by means of the unit configuration soft-ware, even with the switchboard in service.

HardwareThe device consists of a central unit housed insidethe auxiliary compartment of the switchgear and ofa user interface located on the door of this com-partment.The two pieces of apparatus are connectedtogether by means of a simple communicationcable. The user interface can be replaced keepingthe central unit in service and guaranteeing all themeasurement, control and protection functionsduring maintenance work.All the connections are made by means of plug-socket connectors to optimise service and mainte-nance operations.

Machine-user interfaceThe UniGear switchboard becomes extremelysimple to operate by means of the user interfacemade available by the REF542plus unit.

All the apparatus control operations, readout ofmeasurements, detection of signals andparameterisation of the functions can be carriedout directly from the front of the unit or by means ofa laptop computer connected to the optic commu-nication gate located on the front.

Central unitThe central unit consists of modular electronicmodules with the functions described below.• Feeder. The apparatus is fitted with a

multivoltage internal feeder and can operatefrom 48 to 220 Volt d.c. Thanks to its digitaltechnology, consumption is very low.

• Digital inputs. Each unit is fitted with a minimumof 14 digital inputs to interface the apparatuscontained in the switchboard, such as thecircuit-breaker and the earthing switch. Thesecan be increased up to a maximum of 42. Theyoperate between 20 and 250 Volt d.c. and arefreely programmable.

• Digital outputs. The digital outputs consist offree contacts made available by bistable relays.Each unit is provided with at least 8 outputs tooperate the switchgear apparatus and theminimum signals required. These can beincreased up to a maximum of 24. They operateup to 250 Volt d.c./a.c. and are freely program-mable.The output dedicated to the circuit-breakeropening control can carry out control of circuitcontinuity.By means of the static outputs with which it isfitted (from 1 to a maximum of 3), it is possible tointerface conventional supervision systems bymeans of active and reactive power measure-ment with impulse emitter.

• Analogue inputs. Each unit is fitted with 8analogue inputs to carry out measurements andprotections.The signals coming from conventional current(/1 and 5A) and voltage (/100 and /110V)transformers, or from measurement sensors(Rogowski coil and resistive divider) can beacquired.

• Analogue outputs. The 4 analogue outputs theunit can be provided with make it possible tointerface conventional supervision systems bymeans of the integrated measurement functions.Each output can be freely programmed as0...20mA or 4...20mA.

The REF542plus unit integrates allthe secondary functions relevant to aswitchgear unit in a single modulefitted with watchdog.Thanks to the flexibility of its soft-ware, the unit is able to satisfy a vastrange of installation requirements.The high level of functionality of theREF542plus unit is supported by asimple and easy-to-use user inter-face.

31

1.14

REF542plus REF542plus

CommunicationThe REF542plus unit can be connected withsupervision and process systems by means of theintegrated communication function.This means the apparatus becomes the windowthrough which the system accesses all theswitchgear information and makes the followingfunctions possible:• Monitoring• Control• Parameterisation of the protection functions• Measurements• Storage of events• Monitoring of all operating apparatus• Disturbance oscillography.The following protocols are available for connec-tion to the supervision and automation systems:• ABB SPA-bus• LON-bus in accordance with ABB Lon Applica-

tion Guide (LAG 1.4);• IEC 60870-5-103 (in accordance with VDEW

specifications);• MODBUS RTU.Use of the LON-bus protocol and relative LIB542library allows integration of the REF542plus unit inABB supervision systems.Using the hardware configuration with two gateswith the MODBUS RTU protocol, it is possible torealise redundant type system architectures, orindependent connections to two different systems(for example, a supervision SCADA and a processDCS).

SynchronisationBy means of a dedicated optic input, theREF542plus unit can be connected to an externalmaster clock (typically a GPS) for synchronisation.When synchronised using this method, theREF542plus units guarantee a precision inchronological recording of the events of onemillisecond or better.• Dedicated optic input for synchronisation.• Recording of events with a precision of one

millisecond or better.• Protocol accepted: IRIG-B.

Synchronisationdevice

GPS signalreceivingantenna

Concentrator andsynchronisation

device

Concentrator

Supervision andcontrol station

32

Automatic transfer systems

Single-line diagram of aUniGear switchboard withREF542plus architectureapplied, suitable for carryingout automatic and manualtransfer (ATS), as well asthe switchgear protectionsand measurements.

Automatic transfer systems are used to ensuremaximum service continuity, supplying the powerusers uninterruptedly.All this is possible using various systems basedon different 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 andinstruments. They guarantee average transfertimes and can therefore be used in installationswhere voltage 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 REF54plus unit can be used in the 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 the complexity ofthe software transfer logics.The switchboards equipped with REF542plus,suitably programmed, are a complete and efficientsystem able to manage transfer between onepower supply 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 switchboard with supervision of theuser personnel.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 discon-nected when transfer has taken place. The appli-cations described do not require additionalinstruments.

33

1.15

HSTSThe System HSTS (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 switchboard, is able to transfer distribution of power from themain switchgear unit to an alternative emergency supply in few milliseconds. This avoids long and costlymachine stoppages, damage to production equipment, and dead production restarting times.The HSTS SUE 3000 system makes possible to get transfer times equal to 100 ms with the use of all theconventional circuit-breakers and 30 ms with WM1 circuit-breakers equipped with the magnetic actuatorin the high speed version and up to 1250 A.

HSTS system in the con-figuration with two circuit-breakers without bus-tie:when the lack of voltage inthe main power supply unitof the switchboard is de-tected, the closing com-mand of the reserve unit andthe opening command ofthe main unit are launchedsimultaneously.

HSTS system in the con-figuration with three circuit-breakers with bus-tie: whenthe lack of voltage in one ofthe two power supply unitsis detected, the closingcommand of the bus-tie andthe opening command forthe switchgear unit withoutvoltage are launched simul-taneously.

Unit 1 Unit 2

N.O. N.C.

Unit 1 Unit 2

N.C. N.C.

N.O.

34

Typical units and technical data

Single-line diagram of typical units

IF - Incoming/outgoingfeeder

BT - Bus-tie R - Riser RM - Riser withmeasurements

M - Measurements IFD - Direct incoming/outgoing feeder

IFDM - Direct incoming/outgoing feeder with

measurements

DF - Switch-disconnectorunit

Rem

ovab

le

With

draw

able

With

draw

able

Rem

ovab

le

With

draw

able

35

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

36

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

37

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

1100mm versions. The instrument compartment of the unit from 3150A to 4000A is only available in the 705 and1100mm 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

with

gas

exh

aust

duc

t

38

39

2UniGear Double Level

Page Cap.

Description 40 2.1

Characteristics 42 2.2

Typical units and technical data 44 2.3

40

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 orwith contactors. It can be used as amotor control center for applicationsup to 12 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 switchboard.The switchboard requires accessfrom the rear for the installation andmaintenance procedures, whilst allthe service operations are carriedout from the front.The double-level UniGear switch-board can be used in two typicalconfigurations:• Complete with double-level.• Compound with simple and

double-level.

UniGear is a single busbar systemswitchboard 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 switchboard 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 proce-dures are guaranteed.The double-level UniGear switch-board stands primarily for its efficientuse of space. All the configurationsallow drastic reduction of the spaceoccupied, with special regard to thewidth of the switchboard (30...40% intypical configurations).

Complete double-levelconfiguration.

41

2.1

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 distributionswitchboards, with a limited numberof outgoing feeders.The field of application of the com-pound solution is, on the other hand,for main distribution switchboards,with high rated currents (3150 Amaximum current of the incomingfeeders) and numerous outgoingfeeders.

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.

42

Characteristics

CompartmentsEach panel consists of two superimposed units [1st level and 2nd level] and each unit is thereforemade up of three independent power compart-ments: apparatus [A], busbar [B] and feeder [C].There is metallic segregation between all thecompartments.In its middle part, the panel is fitted with a compart-ment to take the auxiliary instruments of both theunits [D]. This solution means the machine-userinterfacing apparatus is at a convenient height. Inthe top part of the panel, an additional compart-ment is available to house any further instrumentsprovided [d].The arc proof switchboard 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,allow 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 theswitchboard [e]. Each compartment of the unitplaced on the 1st level is fitted with a flap posi-tioned on the side of the switchboard. The pres-sure generated by the fault makes this open,allows the gas to pass into the duct. This solutionmeans the units placed on the 2nd level are notinvolved by 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 from the switchboard of theapparatus (circuit-breakers, contactors and trucksmeasurements) placed on the two levels from itsrelative compartments takes place by means of asingle dedicated fork-lift truck. This truck can alsobe used for the same procedures for the single-level units.The busbar and cable compartments are accessi-ble from the rear of the switchboard 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 theswitchboard.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 be useddepending on the rated voltage, on the unitdimensions and on the cross-section of thecables.

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 switchboards. Theseunits are positioned on the 2nd level, whereas theincoming/outgoing feeder units are included in the1st level. The bus-tie units can be fitted with currenttransformers on the load side of the circuit-breakerfor busbar measurement. Installation of the currenttransformers on the supply side is also possible torealise special protection schemes. The risercompartment is also available in the version withwithdrawable instrument truck with voltagetransformers with fuses [RM].The compound configuration with simple anddouble-level requires connection between the twoswitchboards by means of the connection unit.This unit makes all the connections between thetwo types of switchboard (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 voltagetransformers with fuses [JM]. These units arepositioned on the 2nd level, whereas the incoming/outgoing feeder units are included on the firstlevel.

43

2.2

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

44

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

45

2.3

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 BT Bus-tie1st IF Incoming/outgoing

2nd R Riser1st IF Incoming/outgoing

2nd RM Riser with measurements1st IF Incoming/outgoing

2nd J Connection 1250A1st IF Incoming/outgoing (2)

2nd JM 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 BT Bus-tie1st IF Incoming/outgoing

2nd R Riser1st IF Incoming/outgoing

2nd RM Riser with measurements1st IF Incoming/outgoing

2nd J Connection 1250A1st IF Incoming/outgoing

2nd JM 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 pages 20-21.

Unit compartmentsA ApparatusB Main busbarsC FeederD InstrumentsE Gas exhaust ductWidth Depth

Hei

ght

46

47

3UniGear type ZVC

Page Cap.

Description 48 3.1

Characteristcs 50 3.2

Typical units and technical data 52 3.3

48

IF IFIF BT R IF

IF IF IFIF IF IF IF IF

Description

The UniGear range is completed by the compactcontactor unit with fuses. This uses vacuumcontactors and is designed specificallyfor motor, transformer and capacitorbank switching and protection for ratedvoltages up to 7.2 kV and rated currentsup to 400 A. Thanks to the use of fusesas the main means of protection, it canbe used in installations with faultcurrents 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, allowingefficient use of space in electrical installations.The most evident characteristic of this unit is itsextreme compactness, just 325 mm. It thereforefinds ideal application in installations with a highnumber of contactor outgoing feeders or insituations with very limited space available.The use of the contactor unit with fuses is prefer-able to the use of circuit-breakers when a highnumber of daily operations are required.The interrupters for use in the contactor guaranteean extremely high number of closing and openingoperations under normal load conditions and with amaximum rated short-time withstand current of 4 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, allow-ing the contactor to be used in installations evenwith high 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 switchboard components, but suitable in anycase for the fault current available on the load sideof the fuses.

49

3.1

Electrical characteristics

Rated voltage

Rated insulation voltage

Rated power frequency wistand 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 thecontactor 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(busbars and appara-tus) by the structure ofthe switchboard and onthe load side (feeder)by the limiting propertiesof the fuses.

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 considerable reduction in costs.The unit can be coupled directly with the main switchboard, with possibilityof extension on both ends of the switchboard. 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.

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

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50

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 switchboard is normally fitted with aduct for evacuation of the gases produced by anarc.All the units are accessible from the front andmaintenance and service operations can thereforealso be carried out with the switchboard wall-mounted.The compartments are segregated from eachother by metallic partitions.

Integration of the componentsThe switchboard is built up around three basicfunctional structures, consisting of macroblocks ofepoxy resin where the components of theswitchgear are incorporated.The top block [A] contains the whole system ofbranch connections (towards the main busbarsand towards the cable terminals) and the fixedcontacts (for connection of the contactor 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 service positionand vice versa. In the case where backfeed of theunit from the cable side is not possible, the bottomsegregation shutter of the latter could not beinstalled. Even in the unlikely case of backfeed,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 switchboard after having removed thecontactor and the shutter segregation system. Theunit can also be equipped with toroidal transform-ers placed on the power cables in the feedercompartment.Each unit can be equipped with an earthingswitch to earth the cables. The earthing switch isfitted with short-circuit making capacity up to 12.5 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 theswitchgear 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 canbe used, depending on the rated voltage and onthe cross-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-polesvoltage transformer complete with protectionfuses. The voltage transformer must be used forsupplying the coils of the contactor operatingmechanism.The contactor is fitted with medium voltage fusesfor protection of the operated feeders. Coordina-tion between contactor, fuses and protection unit isguaranteed in accordance with the IEC 60470Standards for apparatus in class C.

51

3.2

C

B

A

The monobloc also acts as a fuse-holder frameand is preset for installation of one or two sets offuses per phase with average type of dimensions and striker, according to the BS 2692 Standard, with a maximum length of 454 mm.The contactor has an automatic opening devicewhen even a single fuse blows. This same devicedoes not allow the contactor to be closed wheneven a single fuse is missing.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 contactor dedicated tothis unit uses an automatic coupling system. Thisis activated automatically during movement of theapparatus from the racked-out position to theservice position and vice versa.

52

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-poles voltage transformer for supplyingthe control circuits

Typical motor start-ups

Direct

Reverse direction

Reactor

Autotransformer

Star-delta

Standard components

Accessories

Alternative solutions

53

3.3

B

C

D

A

E

C

A

E

D

machines must be positioned at the end of theswitchboard. The contactors used to operate eachmotor are interlocked together by means ofelectromechanical devices. These operate bymeans of locking magnets with active logics andtherefore auxiliary voltage cut-off makes the lockoperative.The starting and switching sequences can be fullyautomated by means of the REF542plus unit. Theunit software makes the control logics and its greatflexibility allows it to be adapted efficaciously tothe characteristics of the machine to be operated.The interlocks between the contactors dedicatedto operation of the machine can also be managedsafely 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 switchboard can, however, also be used forcomplex starting, which requires the use ofseveral contactor units.The connections between the various units usedduring the starting and running stage, such asbetween the machines (motor, reactor,autotransformer), are carried out using cables.The phase inversions are carried out directly onthe output of the switchgear by means of thepower cables.The units which make the star centre of the

... 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

Notes(1) The height of the unit is

a function of the heightof the instrument com-partment, available inthe 675 and 1070 mmversions.

Width

Depth

Hei

ght

(1)

Hei

ght

with

gas

exh

aust

duc

t

Unit compartmentsA ApparatusB Main busbarsC FeederD InstrumentsE Gas exhaust duct

54

Notes

55

ABB Trasmissione & Distribuzione S.p.A.Unità Operativa Sace T.M.S.Via Friuli, 4I-24044 DalmineTel: +39 035 395111Fax: +39 035 395874E-mail: sacetms.tipm@it.abb.comInternet://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: info.ejf@cz.abb.comInternet://www.abb.com

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3.04