Circuit Breaker Presentation

7/31/2019 Circuit Breaker Presentation

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SWITCH


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FUSE

NOT USED IN A TRANSMISSION

NETWORK AS IT WOULD FAIL TOINTERRUPT.


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Power

plantTransformer Transformer

Local

distribution

net work

Transmission

line

Switch

Yards

Switch

Yard

Power Transmission system


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CLASIFICATIONN OF CIRCUIT BREAKERS

Based on VoltageLow- less than 1kV

Medium - 1kV to 52kV

High/Extra High- 66kV to 765kV

Ultra High -above 765kV

Based on location

Indoor

Outdoor

Based on External design

dead tank

Live tank

Based on Interrupting media

Air break

Air blast

Bulk oil

Minimum oil

SF6 gas insulated

vacuum


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DEAD TANK TYPELIVE TANK TYPE

CLASIFICATION OF AIS BREAKERS


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ACB

AIR

ABCB

BOCB

OIL

MOCB

DOUBLE PRESSURE

SF6

SINGLE PRESSURE

VACUUM


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MOCB


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Axial blast - Contraction chamber principle in MOCB


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Cross blast in MOCBs


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SF6 GAS PROPERTIES


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SF6 - DOUBLE PRESSURE


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First generation interrupter-Double pressure type

Closed Position

Opening Position

Open Position


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DOUBLE PRESSURE SYSTEM

SINGLE PRESSURE SYSTEM


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Normal Puffer Interrupterfor 145-800kV voltage class


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VACUUM


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72.5kV Minimum Oil Circuit

Breaker type HLC


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145kV Minimum Oil Circuit

Breaker type HLD


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Arc interruption in duel flow conducting nozzle interrupter


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Arc quenching process


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145kV hydraulic mechanism operated SF6 gas breaker


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245kV SF6 Circuit Breaker type

3AV1


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3AT2/3


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3AT4/5

800kV Type 3AT4/5 SF6 gas circuit breaker


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800kV Type 3AT4/5 SF6 gas circuit breaker


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Hydraulic operating mechanism


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Spring operated mechanisms


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Pneumatic mechanism

COMPARISON OF ELECTROHYDRAULIC - PNEUMATIC - SPRING

MECHANISMS


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MECHANISMS

Electro Hydraulic Pneumatic Spring

1. No compressor is required Hydraulic pump ismaintenance free and directly coupled to motor.

Compressor is required, which needs routinemaintenance (at least once a year). Compressors arenormally coupled to motor by belt, which is a weak

link. Also intake air filters of compressors requirefrequent change (Every Six months in pollutedatmosphere)

No compressor is required Hence no associatedmaintenance problems.

2. All parts permanently immersed in oil - No scope forinternal corrosion or rusting.

All parts exposed to atmosphere. In addition,atmospheric air is compressed and releasedduring closing / opening operation. Duringexpansion, traces of moisture present in air inspiteof purification / drying of air, condense on metal

parts of the mechanism causing corrosion andrusting.

All parts exposed to atmosphere Heaters providedto prevent condensation of moisture on parts ofmechanism

3. Minimal piping Oil flow is through ducts in valveblock assembly No scope for external leakage Internal leakage, if any, would only cause morefrequent operation of motor at worst.

Piping is involved - Scope for leakage. No piping - No leakage.

4. No mechanical latches.The differential piston principle used clearly definesthe switching condition and ensures that this ismaintained should there be a fall in pressure and that"creeping" trip out is prevented.

Latches are to be checked for disturbances in settings

after specified no. of operations

Latches are to be checked for disturbances in settings

after specified no. of operations.

5. Small in size, compact and robust construction.Reliability very high.

Complex construction with many componentsand moving parts - Reliability very low.

Simple in design and construction. Less componentsand moving parts, hence reliable.

6. Two Close-Open operations are possible after failureof supply to motor.

One Open-Close-Open or Close-Open-Close

operation is possible after failure of supply to motor.

One Open-Close-Open operation is possible after

failure of supply to the motor.

COMPARISON OF ELECTROHYDRAULIC - PNEUMATIC - SPRING

MECHANISMS


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MECHANISMS

Electro Hydraulic Pneumatic Spring

7 No additional damping system The damping requiredfor both closing and opening is provided by the

hydraulics of the operating mechanism.

Additional damping system is required which is to beroutinely checked and maintained.

Additional damping system is required which is to beroutinely checked and maintained.

8 No inter-posing mechanism. The piston systemtransmits the operating energy direct to the operatingrod.

Inter-posing mechanism with linkages is required fortransmission of operating energy to the movingcontact system.

Inter-posing mechanism with linkages is required fortransmission of operating energy to the movingcontact system.

9 Low noise level High noise level Low noise level

T ti f i it b k


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Testing of circuit breaker

Type tests

High power tests

Direct tests

synthetic tests

Short circuit tests

Switching performance tests

High voltage tests

Mechanical and environmental tests

Temperature rise test

Routine tests

Mechanical operations test

Measurement of contact resistance

Voltage withstand test on control circuit

Power frequency withstand test on main circuit

High pressure test on Hydraulic mechanism

SF6 gas tightness test

Pump charging time for operations

Leak testing hydraulic mechanism

N2 leak test on accumulator

Thermal Assist Interrupter


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Thermal Assist Interrupterfor 72.5-170kV voltage class

Thermal Assist Interrupter


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Thermal Assist Interrupterfor 72.5-170kV voltage class


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SF6 gas circuit breaker SF6 gas operated mechanism


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SF6 gas operated mechanism


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SF6 gas operated mechanism


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Compact switchgear


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Circuit breakers with composite insulators

Explosion proof

Light weight

Single piece of any length

No L/D constraint

Higher creapage can be achieved

Comparatively costly

No of joints can be reduced


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SF6 gas insulated substation

SB6 offer extension : MCI the Integrated Compact Module


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Functions :

-INTERRUPTION

-ISOLATION

-MEASURING

-CONTROL (& PROTECTION)

Up to 170kV 2000A 40kA


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Documents

Circuit Breaker Presentation