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SF6 CIRCUIT BREAKER
- 1. Seminar On “Sf6 circuitbreaker” Under The Guidance Of :- Mr. S.S Mohapatra, Lecturer
- 2. cOntentS • Introduction • SF6circuit breaker • Why SF6?? • Types of SF6 CB • Overview of an arc • Working principle • Principle of arc extinction • Circuit breaker connected with bus bar • Physical and chemical properties • Advantages of SF6 CB • Disadvantages of SF6 CB • Limitation • Conclusion • References
- 3. In moderntimes, high voltages are used for • Power system • Industry • Research laboratories For safety and protection We use one of the protection device is SULPHUR HEXAFLUORIDE (SF6 ) gas circuit breaker. They were first introduced in the mid
- 4. A circuit breakerisan equipment which can makeor break acircuit either manually or automatically under normal conditions. break acircuit under abnormal, short circuit , overload condition or any other fault. A circuit breaker in which thecurrent carrying contactsoperate in sulphur hexafluoridegas(SF6) isknown asSF6 circuit breaker. SF6 CBsmadefrom 72-800KV with interruption current is20 to 63KA and rated current of 1200 to 12000A.
- 5. WHY SF6 GAS? • HiGH eLectrO-neGatiVitY • HiGH DieLectric StrenGtH • LOW LiQuificatiOn temPerature • GOOD arc QuencHinG
- 6. Types of sf6circuiT breaker 1. Single interrupter SF6 CB(upto 245kv) 2. Two interrupter SF6 CB(upto 420kv) 3. Three interrupter SF6 CB(upto 800kv) Single interrupter Three interupter
- 8. During theseparation of contacts, due to large fault current and high current density at the contact region the surrounding medium ionises and thus a conducting medium is formed. This is called he ARC.
- 9. Fixed contact Moving contact ARC Fixed contact Moving contact ARC ARC IS QUENCHED BY SF6GAS IN A CIRCUIT BREAKER OPERATING PRINCIPLE OF CIRCUIT BREAKER
- 10. Factorsresponsiblefor arc:- Potentialdifferencebetween thecontacts Ionised particlesbetween thecontacts By removing any oneof thesethearc can be quenched.
- 11. Arc extinction throughSF6 gas in circuit breaker
- 12. Factor responsiblefor arcresistance:- Degree of ionisation Length of the arc Cross section area of arc
- 13. Line Isolator Circuit Breaker Bus Bar #1 BusBar #2 Bus Isolator 2 Bus Isolator 1 circuit breaker connected with bus bars
- 14. 1. Chemically inert1.Chemically inert 2. Non-toxic2. Non-toxic 3. Non-corrosive3. Non-corrosive 4. Non-flammable4. Non-flammable Physical & Chemical properties 5. Odourless5. Odourless 6.Electrical insulator6.Electrical insulator
- 16. •Arched SF6 gasis poisonous. •Contribute to the manmade greenhouse effect. •Continuous monitoring devices are required. •Special facilities are required for transportation of SF6 gas. DISADVANTAGES OF SFDISADVANTAGES OF SF66 CBCB
- 17. SF6 gasfound to be greenhouse gas that causes environmental hazards • 100% SF6 is more hazardous. • Experimentally suggest that 69%SF6 / 31%N2 gas mixtures is better in circuit breaker and non-hazardous. • Further research is going on to replace or mixture of gases for better dielectric strength without environmental problems. LIMITATION
- 18. SF6 Circuit breakersare mostly employed for high voltage applications. For protection and reliability of an electrical substation of an electricity generation, transmission and distribution system where voltage is transformed from high to low or the reverse using transformers. The countless advantages of this SF6 CB gas has to offer will takeusto new heightsin theprevalent power system.
- 19. reference HIGH VOLTAGEENGINEERING -M.S NAIDU,V.KAMARAJU –TheMCGraw-hillcompanies 4th edition 2009 ISBN 97-80070669284, chapter-1,2 PRINCIPLES OF POWER SYSTEM-V.K MEHTA ,ROHIT MEHTA-S.Chand &company pvt. Ltd, 1st edition 2013 ISBN 81-219-2496-0,CHAPTER-19 WWW.ijettjournal.org
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