This document summarizes a seminar presentation about circuit breakers. It defines a circuit breaker as equipment that can break an electric circuit manually or automatically under various load conditions. It then describes the operating principle of circuit breakers and the arc phenomenon that occurs when contacts are separated. Various types of circuit breakers are discussed, including oil, air blast, SF6, and vacuum circuit breakers. The document focuses on the advantages of SF6 circuit breakers for high voltage applications, as SF6 gas is effective at extinguishing arcs due to its ability to capture electrons from arcs.

1. Giani Zail Singh Punjab Technical Campus, Bathinda
Department of Electrical Engineering
A Seminar Presentation
Topic on
Circuit breaker
For
The Partial Fulfillment
of
B.tech
Electrical Engineering
Submitted To:-Er Manveer kaur Submitted By:- karmandeep singh bhullar
1145452
2k11
Electrical Engg.

2. CIRCUIT BREAKER

3. WHAT IS A CIRCUIT BREAKER?
• A circuit breaker is an equipment that breaks a circuit either
manually or automatically under all conditions at no load, full load or
short circuit.

4. Operating Principle
Two contacts called electrode remains closed
under normal operating conditions. When fault
occurs on any part of the system, the trip coil
of the circuit breaker get energized and
contacts are separated.

5. Arc Phenomenon
• An arc is struck when contacts are separated. The current is thus able to
continue. Thus the main duty of a circuit breaker is to distinguish the arc
within the shortest possible time.
• The arc provides the low resistance path to the current and the current
in the circuit remains uninterrupted.

6. The arc resistance depends upon the
following factors.
Degree of ionization
Length of the arc
Cross Section of the arc

7. Methods of Arc Extinction
High Resistance Method
Low Resistance Method

8. TYPES OF
CIRCUIT
BREAKER
OIL
CIRCUIT
BREAKER
AIR BLAST
CIRCUIT
BREAKER
SF6
CIRCUIT
BREAKER
VACCUM
CIRCUIT
BREAKER

9. Breaker Used In 132KV Grid
Station
• Oil Circuit Breaker
• Vacuum Circuit breaker
• SF6 Circuit Breaker

10. Air
cushion
Bulk Oil Circuit breaker

11. Low Oil Circuit Breaker
Consists of two parts.
Supporting
Chamber.
Circuit-Breaking
chamber( consist
of fixed and
moving contact)

12. Disadvantages Of Oil Circuit
Breaker
• It is inflammable and there is a risk of fire.
• It may form an explosive mixture with air.
• It requires maintenance.
• Absorbs moisture, so dielectric strength reduces.
• Oil leakage problem.
• Oil has to be replaced after some operations because of the
carbonization of oil.

13. 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.

14. Vacuum Circuit Breaker

15. Advantages
• Compact, reliable and have longer life.
• No fire hazards.
• No generation of gas during and after operation.
• Can interrupt any fault current.
• No noise is produced while operating.
• Require less power for control operation.

16. SF6 Circuit Breaker
1. Sulphur Hexafluoride (SF6) gas is used as an arc
quenching medium.
2. SF6 is an electro-negative gas.
3. It has strong tendency to absorb electrons.
4. When contact are opened in a high pressure flow
of SF6 gas, arc produced.
5. Free electron in the arc are captured by the gas.
6. Which build up enough insulation strength to
extinguish arc.
7. it is much effective for high power and high
voltages services,

17. SF6 Circuit Breaker

18. Advantages
• Simple construction, less cost.
• SF6 gas is non flammable, non toxic & chemical inert gas.
• Same gas is recirculated in the circuit.
• Maintenance free C.B.
• Ability to interrupt low and high fault current.
• Excellent Arc extinction.

19. Advantages Of SF6 Over Oil Circuit
Breakers
• Short arcing time
•Can interrupt much larger currents
•Gives noiseless operation due to its closed gas
circuit
•No moisture problem
•No risk of fire
•No carbon deposits. So no tracking and insulation
problems
• Low maintenance cost

20. THE END