Spring operating mechanism for highvoltage circuit breakers

Model FSA 1

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Advantage ABB

ü 120 years of technology and innovation

ü Unparalleled domain competence

ü Vast global experience

ü Total solution provider

ü Large installed base

ü Environment-friendly technologies

ABB (www.abb.com) is a global leader in power andautomation technologies that enable utility andindustry customers to improve performance whilelowering environmental impact. The ABB Group ofcompanies operates in around 100 countries.

ABB’s Power Technologies’ division offers electric,gas and water utilities as well as industrial andcommercial customers a wide range of products,system and service solutions for powertransmission and distribution, integrated solutionsfor power generation plants, utility automation andbulk power transmission.

The product offering covers a wide spectrum oftechnologies across the entire voltage rangeincluding indoor and outdoor circuit breakers, airand gas insulated switchgear, disconnectors,capacitor banks and reactive power compensators,power and distribution transformers as well asinstrument transformers.

ABB – a global leader

ABB in India serves utility and industry customerswith the complete range of ABB’s global offering.The company has a vast installed base, extensivelocal manufacturing across 8 units and acountrywide marketing and service presence.

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Introduction

Main features and advantagesn The immediate availability of stored energy

without any losses ensures constant contacttravel behaviour

n A minimum number of mechanicalcomponents increases the reliability

n No seals or valvesn Accessible and clear arrangement of

components in the operating mechanism cubiclen Easy access to all components without

obstruction, after lowering the outer housingn The closing spring can be tensioned manuallyn Maximum availability and reliabilityn Minimal maintenance costs

DesignThe principal components and the design can beseen in Figure 1. The well-sized position and springtension indicators are readily visible through theobservation window in the door, and allow positiveidentification of the breaker position, and of thestate of tension of the closing spring. The electricalmonitoring and control units are easily accessibleafter opening the door. The electrical leads are alltaken to the terminal blocks. The sheet metalhousing including the door, can be removed forready access to all the internal components. Theclosing and opening springs are arranged on thetwo sides. All movements are frictionless dampedby means of a dashpot.

Mode of operationThe spring operating mechanism, the design ofwhich is shown schematically in Figure 2, consistsessentially of two tension spring systems. Closingspring(5) is tensioned by means of the motor(13),over the worm gear drive(21). This provides theenergy for a closing operation, which will tensionthe opening spring(6) during the closingoperation.

Charging of closing springThe main shaft(1) is rotated through 180 degreesvia the worm gear drive(21), by means of themotor(13) or the hand crank(14), in this waytensioning the closing spring(5).

Availability is of paramount importance for efficientelectricity supply. Reliability of lines, relays and highvoltage apparatus are important factors whichincrease availability. With improved designs of SF6high voltage circuit breakers, increased attention ispaid to reliability. International statistics, like Cigre’sreport, have shown that 80% of the failures in acircuit breaker are of mechanical origin. Most ofthese failures have been traced to the operatingmechanisms. The dynamic mechanical and

electrical performance of a circuit breaker iscomplicated. Within milliseconds, theoperating mechanism has to change the circuitbreaker from a perfect conductor to a perfectinsulator. A failure in the operating mechanism mayresult in a failure of the total breaking operation. TheFSA 1 operating mechanism is characterised by anespecially robust, simple, and thereby functionallyreliable design. It is suitable for three pole as well assingle pole application.

Closing operationOn a closing signal, the locking latch(7) isreleased from the main shaft and closing spring(5)discharges itself. In this way the transfer camsrotate via the transfer lever(9). Switching shaft(2)is actuated and the breaker closes,simultaneously tensioning and locking theopening spring(6). The motor(13) tensions theclosing spring(5) are every closing operation. It isstopped via the motor limit switch(16).

Opening operationOn an opening signal, locking latch(8) is releasedfrom switching shaft(2) and the opening spring(6)discharges, thereby opening the breaker.Auxiliary contacts(15) are mechanically linkedto the switching units and follow the breakeroperation exactly.

Mounting of the operatingmechanismThe operating mechanism cubicle (Figure 1),containing the spring operating mechanism FSA 1as well as the control and monitoring units iseasily attached to the circuit breaker. Aftermounting, the mechanism cubicle to the polesupport the operating rod is coupled to thebreaker poles. In case of single pole operation thecontrol and monitoring elements are positioned ineach mechanism cubicle. Special provisions forsupporting the operating mechanism duringassembly are not required.

MaintenanceWith minimal maintenance, the spring operatingmechanism FSA 1 offers distinct advantages,which contribute to a reduction in operationalcosts.

Lubrication of the transmission shafts and worm-gears as well as the gear wheels is required forthe first time only after 2500 CO switchingoperations, while an overhaul of the completeoperating mechanism should be carried out after5000 CO operations.

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1 Main shaft

2 Switching shaft

3 Hydraulic damper

4 Discharge lever

5 Closing spring

6 Opening spring

Fig. 1Design and internal view of the spring operating mechanism FSA 1.

References to Figures 1 and 2

7 C locking latch

8 O locking latch

9 C transfer lever

10 C release coil

11 O trip coil

12 Breaker operationscounter

13 Motor

14 Hand crank (formanual operation)

15 Auxiliary contacts

16 Motor limit switch

17 C manual operation

18 O manual operation

19 Spring tensionindicator for theCO spring

20 Position indicator

21 Worm gear drive

Rear View Front View

21

4

13

15

1

9

2

10

3

5

12

1920

17

10

18

1

21

92

11

6

5

Fig. 2Schematic layout of the spring operating mechanism FSA1. Reference as given on Page 4.

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Optional features

AuxiliarAuxiliarAuxiliarAuxiliarAuxiliary contacts. y contacts. y contacts. y contacts. y contacts. The operating mechanism canbe supplied with 6 N/O plus 7 N/C additionalauxiliary contacts.

PrPrPrPrProtective coverotective coverotective coverotective coverotective cover for the terminals (only for theincoming AC cables). Made of transparent plexiglass.

Lockable cover Lockable cover Lockable cover Lockable cover Lockable cover for control panel. A hinged lockablecover protects the entire operator’s panel.

Lighting arLighting arLighting arLighting arLighting arrangement for cubicle illumination.rangement for cubicle illumination.rangement for cubicle illumination.rangement for cubicle illumination.rangement for cubicle illumination.

Fuses. Fuses. Fuses. Fuses. Fuses. UK 10,3-HESi or HRC fuse link. Quantity,type and position in circuit diagram to be statedwhen ordering.

Central contrCentral contrCentral contrCentral contrCentral control cubiclol cubiclol cubiclol cubiclol cubicle. This is needed if threepole operation is required for single phase operatedbreakers.

Technical data

Motor

Universal series motor for voltage

110-125 V or 220-250 V. a.c or d.c.

Starting Normal

Rated current current

voltage Instantaneous at d.c.

V approx A approx A

220 20 4

110 40 8

Spring charging time 15 sec. max.

Operating coils

Operating Rated voltage Power

coil V, d.c consumption

approx. W

Closing coil 110-125, 220-250 500

Opening coil 110-125, 220-250 500

Voltage operating range for the motors and the

operating coils meet the requirements in

IEC 62271-100.

Auxiliary contactsBreaking current

Rated Rated DC ACvoltage current 20 ms cosø = 0,95V A A A

110 20 4 20

220 20 2 20

The operating mechanism normally includes 6 N/O

and 7 N/C spare auxiliary contacts.

Heating elements

Power consumption

Continuously Thermostatically

Rated voltage connected controlled

V, AC W W

210-240 70 140

110-127 70 140

Power frequency test, 50 Hz as per IEC 60694

Auxiliary circuit 2.0 kV

Motor 1.5 kV

Degree of protection as per IEC 529 IP 55

Terminal blocks Through 6 mm² block

Cable-entry plate Size 135 x 200 mm

Testing

The spring mechanism has passed type testing according to IEC 62271-100. Mechanical life test isperformed up to 10,000 operations. Before delivery each operating mechanism has to pass rigorous routinetesting. For each breaker a routine test report is issued showing the actual test result.

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Electrical Functions

The design, data and dimensions are subject to modification.

Fig. 3Basic diagram of the electrical components in the spring operating mechanism FSA 1

F2 Density switch M Motor S13 Control switchF3 Direct on line motor starter E3 Heater Y1 Closing coilF4 Miniature circuit breaker S0 Auxiliary contacts Y2 Shunt trip coil 1K1 Antipumping relay S3 Limit switch Y3 Shunt trip coil 2K2 Interlocking relay, Close and Trip S12 Selector switch

The functions of the electrical components of theoperating mechanism are shown in the basic circuitdiagram (Figure 3)

Closing circuit

The closing coil Y1 can be activated manually via theoperating switch(17) (Figure 1) in the operatingmechanism, or electrically by means of local orremote control.

Interlocking at close

Auxiliary contacts SO ensure that the closing signal isonly transmitted when the breaker is fully open. Thegas density monitor contact F2 controls auxiliarycontactor K2 and blocks the switching commandwhen the SF6 pressure is too low. Antipumping relayK1 cancels the persistent closing signal aftersuccessful completion of the closing operation.

Tripping circuits

The breaker is equipped with two tripping coils Y2and Y3, each independent of the other. These can bemanually activated via the manual switch (18)(Figure 1) in the operating mechanism, or electricallyby means of local or remote control.

Interlocking at trip

Auxiliary contacts SO ensure that the tripping coilsY2 and Y3 can be energised when the breaker isclosed. In the event of too low SF6 density, thetripping circuits are interrupted via the gas densitymonitor contact in F2.

Monitoring and signalling

In order to monitor the operating condition of the SF6gas and the operating mechanism, electrical signalsare employed for remote indication of:

n SF6 gas density too low

n SF6 gas alarm pressure

n Protection switch “Motor supply” tripped

n Protection switch “Heating supply” tripped

n Phase discrepancy via auxiliary contacts S0(only for single pole operated breakers).

Heating circuit

The operating mechanism cubicle is fitted with acontinuous heating system in order to avoid watercondensation. For low temperature operation anextra thermostatically controlled heater is supplied(only for applications lower than -30°C).

Circuit diagram shows operating mechanism when circuit breaker is in ‘off’ position, not pressurised, closingsprings uncharged, no power supply connected and selector switch in position LOCAL.

ABB LimitedHigh Voltage ProductsManeja, Vadodara390 013, IndiaTel: +91 265 2638930Fax: +91 265 2638908email:pt-exports.inabb@in.abb.com

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North

East

West South

Central

1HY

B80

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-040

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.A01

/200

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