GUIDED BY:- Mr. Piyush Sharma

H.O.D (EEE/EE)SS College of Engineering Udaipur (Rajasthan)

PRESENTED BY:- Dilip Kumar Roll no. :-12ECOEE005

TRAINING SEMINARON

CIRCUIT BREAKER

SESSION 2015-16Bachelor of Technology

InElectrical Engineering

CONTENTSCircuit breaker.Types of circuit breaker(C.B).Oil circuit breaker. i bulk oil circuit breaker. ii minimum oil circuit breaker.Air blast circuit breaker.SF6 circuit breaker.Vacuum circuit breaker.

Circuit Breaker• A circuit breaker is a piece of equipment which can Make or break a circuit either

manually or by remote control under normal conditions.• Circuit breaker sense the message from relay and break the circuit.

• Make a circuit either manually or by remote under fault condition.

Circuit Breaker

TYPES OF CIRCUIT BREAKER

• AIR CIRCUIT BREAKER.• OIL CIRCUIT BREAKER.• VACCUM CIRCUIT BREAKER.• SF6 CIRCUIT BREAKER.

Air Circuit Breakers

1.In this Circuit Breaker the arc is elongated using arc runners and arc splitters so as to increase the resistance of the arc.

3.This increases the voltage required to maintain the arc and if the available voltage cannot sustain the arc ,the arc gets extinguished.

2.At current zero ,the recovery voltage across the contacts becomes less than the arc voltage and the arc gets extinguished.

4. The energy in the system inductance at current zero is zero .Hence arc interruption is easier.

Air Circuit Breakers

Advantages and Disadvantages

AdvantagesHigh speed of operationShort arcing timeHigh speed reclosingLess weight as compared to oil

circuit breakersVery less maintenanceNo possibility of explosion

DisadvantagesCost is moreFor complete compress air

installation is requiredFor operation and

maintenance ,highly skilled required

Vacuum Circuit Breaker

• Vacuum is used as an arc quenching medium.• Have greatest insulating strength.• 10-7 to 10-5 pressure is to be maintained.• Used in 11KV panel in control room of grid station.

Vacuum Circuit Breaker

Vacuum Circuit Breakers

Advantages Compact in sizeReliable and long lifeHeavy fault can be interrupted

effectivelyNo gas is generated after arc

extinction operationOperation is not noisyArc energy is lowNo risk of fire

DisadvantagesVacuum has to be maintained at

desired level always

Bulk Oil Circuit Breaker

Advantages

• oil has high dielectric strength.• Oil absorbs arc energy while

decomposing.• Good cooling property of the gas

formed due to decomposition.• It acts as an insulator between the live

parts and earth.

Disadvantages• Long arcing time.• Do not permit high speed of

interruption.• Bulk size.

Bulk Oil Circuit Breakers

Minimum Oil Circuit Breaker

Minimum Oil Circuit Breaker

AdvantagesRequires less quantity of oilRequires smaller spaceMaintenance is lessCost per breaking capacity in MVA is

lessSuitable for both manual and

automatic operation

DisadvantagesPossibility of fire and explosion.Difficult to remove gases from the

space between contacts.Oil deteriorates rapidly due to

carbonizationSmaller quantity of oil, so

carbonization increases.

SF6 circuit Breaker (Properties of SF6 gas)

Rate of rise of dielectric strength is very high.Can be liquefied and stored in steel tanks.Dielectric strength increase linearly with pressure.Gas is inert. Therefore contacts will not get eroded.Gas is non –inflammable , Colorless ,odorless, Non-toxicThermally stable up to 55 degrees.

Sulfur Hexafluoride Circuit Breaker(SF6)

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