ABB Switchgear

HPA SF6-circuit breaker

HPA is a medium-voltage circuit breaker

using SF6 gas as the insulation and break-

ing medium. Its design is compact and

space-saving.

The breaker is also available in a ver-

sion with synchronised making for maxi-

mum damping of transients for different

applications.

The HPA circuit breaker

HPA is a medium-voltage circuit breakerusing SF6 gas as the insulation andbreaking medium. Its design is compactand space-saving.

The HPA breaker works extremely“smoothly“, which means that no dange-rous overvoltages arise through currentcut-off or restriking. It is therefore verysuitable for the majority of operating

situations, including the breaking of motorloads and capacitors.

The breaker is also available in a ver-sion with synchronised making for maxi-mum damping of transients when switch-ing in parallel capacitor banks.

The excellent electrical and mechanicallifetime of the HPA breaker means that itrequires only a minimum of maintenance.

The breaking pole indifferent positions.

The HPA breaker works according to thepuffer principle, implying that whenbreaking, the gas is compressed between afixed plunger and a moving cylinder andthen blown on to the arc between the fixedand moving arc contacts (see figure).

When the breaker is closed, the currentflows via the main contacts and the cylinder.

When a tripping impulse is given, the

cylinder moves downwards, whereupon theupper main contact opens and the currentcommutes over to the arc contact. At thesame time, the gas in the cylinder is com-pressed. When the nozzle has left the arccontact, the compressed gas is blown alongthe arc and cools it. The breaking process iscompleted as the current passes throughzero.

Breaking principle

Closed position Breaking Open position

Maincontact

Movingcylinder

Arccontact

Fixedplunger

Nozzle

Breaking gasSF6 (sulphurhexafluoride) gas possesses aunique combination of properties thatmakes it extremely suitable for use incircuit breakers. This has been confirmedby service experience from more than25,000 HPA breakers installed throughoutthe world.

SF6 gas has an insulation strength somethree times higher than that of air at anoverpressure of 2 bar, which is evenhigher than that of transformer oil.

The casing for the breaking poles is madeof cast epoxy resin. The poles are

thoroughlyvacuum-driedafter assemblyand then sub-jected topressure andsealing tests. The

low gas pressure(2.5 bar over-pressure) and thesmall volume (12dm3) mean that thebreaking pole’s

casing can under no circumstances “dis-integrate“ due to negligence, for instanceif it should be dropped during transport.The worst that can happen is that thecasing cracks and the gas pressure drops.

To further increase their reliability, thebreaking poles can be provided withtemperature-compensating transducersthat provide an alarm at the lowest gaspressure permissible upon breaking of fullshort-circuit current.

However, the safety margins are solarge that the poles can cope withbreaking of rated current even withoutoverpressure.

Exploded HPA breakingpole.

SF6 gas properties • High insulation strength• Excellent ability to quench arcs• Chemically stable• Non-toxic• Non-flammable

Model of SF6 molecule.

Breaking poles

HPA breaker withoperating device andbreaking pole dis-assembled.

Operating device

The HPA breaker is provided with asimple and dependable operating devicebased on well established principles incombination with many years of serviceexperience.

The maintenance-free bearings and theease of dismantling and removingbreaking poles and operating devices areexamples of valuable properties thatreduce maintenance costs.

The HPA breaker is operated by aspring-loaded operating device that isnormally tensioned by an electric motor. Itcan also be tensioned manually.

The tripping spring is automaticallytensioned when the breaker is switchedon. After each make operation, the motorstarts and tensions the making spring.

A breaker that is switched on can thenperform an Off-On-Off operation withouthaving to tension the making spring inbetween, which means that the breakercan also be used for fast reconnection (afurther On-Off operation can be madewith a normal time lag).

The breaker has making and trippingcoils for electric operation and can also besupplied with pushbuttons for manualoperation. There is space for an under-voltage release or a further tripping coil.

A counter for the number of operationsand indicators for tensioned/untensionedmaking spring and open/closed breakerare included as standard.

The operating device is easily accessiblein the breaker’s rack and can be easilydismantled and replaced.

The HPA breaker’soperating device.

Lifetime

Principal dimensions for HPA

The HPA breaker requires a minimum ofmaintenance. The gas and the breakingpoles do not need to be replaced and burn-

off of contacts and nozzle due to the arcs isinsignificant. The breaking poles thereforehave a very long lifetime. The high electrical

lifetime is achieved through short breakingtimes. For example, the poles cope with 160breaks at 10 kA without maintenance of the

contacts. The graph on the left shows the

contact lifetime expressed in thenumber of possible breaks at variousshort-circuit currents. The fact thatthe main contacts are never affectedby the arcs is also of great significan-ce for the long lifetime.

In the unlikely event of the break-ing pole requiring repair, this has totake place at the factory since vacuumdrying and pressure and sealing tests

have to be carried out. The breaking polecan then be replaced by a spare pole thatcan be easily mounted on site.

10 000

1000

100

10

10 20 30 40 kA

Electrical endurance ofthe HPA circuit breaker.

Number of interruptions

Short-circuit current

3.6 - 12 kV: 622 mm, 15 - 30 kV: 747 mm3.6 - 12 kV: 617 mm, 15 - 30 kV: 717 mm

Phase distance185 or 210 mm

90 m

m

367

mm

640

mm

4.5

mm

139

mm

Type testing has been carried out in accord-ance with IEC 56 and ANSI c37.09.

The short-circuit tests were performed atABB’s laboratory in Sweden, at KEMA in

Holland, at IREQ in Canada and at Powertestin the U.S.A.

A certificate and test report can beobtained upon request.

Data according to ANSI c37.09

Max. voltage kV 15 26 30

K factor ....................................................................................................................................................................1.3....................................... 1.0......................................1.0

Frequency..............................................................................................................Hz...........................................60..........................................60 .......................................60

Rated holding voltage with alternating voltage testing......kV...........................................36..........................................50 .......................................60

Rated holding voltage with surge testing.....................................kV...........................................95.......................................125....................................150

Rated current.........................................................................................................A .................1200 – 3000.................1200 – 3000..............1200 – 3000

Making capacity................................................................................................kA...........................................58..........................................37 .......................................41

Short-circuit current ......................................................................................kA...........................................28..........................................18 .......................................20

Operating cycle.....................................................................................................................O – 0.3 s – CO/P – 15 s – CO – 1 h – CO

Breaking time ........................................................................................periods..............................................5 .............................................5 ..........................................5

Max. breaking capacity symmetrical ...............................................kA...........................................36..........................................18 .......................................20

Short-time current, 3 sec. ........................................................................kA...........................................36..........................................18 .......................................20

Data according to IEC 56

Rated voltage kV 3.6 – 12 17 24 36

Rated frequency ...............................................................................................Hz............................50...........................50..............................50 ................................50

Rated power frequency withstand voltage .................................kV............................28...........................38..............................50 ................................70

Rated lightning impulse withstand voltage..................................kV............................75...........................95 ..........................125.............................170

Rated current .........................................................................................................A ..................–3150................– 2500...................– 2500 .....................– 1250

Rated (peak) making current ...................................................kA peak ........................100 .......................100..............................79 ................................63

Short circuit breaking current with operating cycle:

O – 0.3 s – CO – 3 min – CO.................................................................kA............................40...........................40.........................31.5 ................................25

O – 3min – CO – 3 min – CO ............................................................... kA............................50.......................... — ........................... — .............................. —

Opening time......................................................................................................ms............................38...........................38..............................38................................38

Opening time for 12 kV 50 kA..............................................................ms............................70.......................... — ........................... — ............................. —

Arcing time, max.............................................................................................ms............................15...........................15..............................15................................15

Breaking time .....................................................................................................ms............................53...........................53..............................53................................53

Breaking time for 12 kV 50 kA.............................................................ms............................85.......................... — ........................... — ............................. —

Making time, max...........................................................................................ms............................75...........................75..............................75................................75

Short-time current .........................................................................................kA............................50...........................40.........................31.5................................25

Principal data for HPA

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ABB Switchgear ABMedium Voltage DivisionBox 1023S-732 27 Arboga, SwedenTelephone: +46 589 851 00Telefax: +46 589 852 90E-mail: medium.voltage@seswg.mail.abb.com

We reserve the right to alter design, dimensions andtechnical data without prior notice.