Symmetrical and nu-symmetrical fault in three phase overhead line, circuit breaker, balanced and unbalanced fault, Transient in RL series circuit.

1. Symmetrical & Unsymmetrical
Fault In Three Phase
Transmission Line
Prepared By:
Siddiqui Arshad hussain
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2. GOVERNMENT
ENGINEERING COLLAGE
DAHOD
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3. Contents
1. Introduction
2. Types of Fault
3. Symmetrical Fault
4. Unsymmetrical Fault
5. Transient in RL series circuit
6. Selection of C.B.
7. Types of C.B.
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4. Introduction
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5. • Under normal conditions, a power system
operates under balanced conditions with all
equipments carrying normal load currents and
the bus voltages within the prescribed limits.
• This condition can be disrupted due to a fault
in the system.
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6. Types of Fault
1. Symmetrical fault
1. LLL fault
2. LLLG fault
2. Unsymmetrical fault
1. LG
2. LL
3. LLG
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7. LLL fault
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8. LLLG fault
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9. LG,LL,LLG fault
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10. Transient in RL series circuit
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11. hars10203@gmail.com

12. Selection of C.B.
• Voltage Rating
• Frequency
• Maximum interrupting capacity
• Continues current rating
• Types of operating mechanism used
• Operating condition
• Maintenance and testing
• Cost
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13. Types of C.B.
• Oil Circuit breaker
• Air blast Circuit breaker
• Vacuum Circuit breaker
• Sf6 Circuit breaker
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14. Reference
• http://www.electrical-
installation.org/enwiki/Selection_of_a_circuit-
breaker
• http://www.electrical-
installation.org/enwiki/Selection_of_a_circuit-
breaker
• Electric circuit (by: R.P. Ajwalia),Pub: Atul Prakashan
• http://www.electrical4u.com/electrical-power-
transmission-system-and-network/
• http://www.skm-eleksys.com/2011/03/transmission-
line-parameters.html
• https://en.wikipedia.org
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