This document discusses auto-reclosing, which is a protective relay scheme used on overhead transmission lines. It aims to quickly reclose circuit breakers after faults to restore power supply while avoiding permanent faults. The document describes the different types of faults, steps for auto-reclosing installation and operation, schemes of operation including live bus/dead line charging. It also discusses factors to consider like protection characteristics, circuit breaker characteristics and types of auto-reclosing like medium voltage and high voltage auto-reclosing. Benefits of auto-reclosing include minimizing power interruptions and maintaining system stability and integrity.

1. MINI PROJECT ON
AUTO-RECLOSING
PRESENTED BY
K.Sandeep (10RC1A0228)
Patan. Rafi(10RC1A0247)
B.Shiva (10RC1A0203)
M.Uday teja(10RC1A0232)
Under the esteemed guidance of
Mr.R.Laveen,M.Tech(Asst.Prof).
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2. AUTO-RECLOSING
• it is placed on over head transmission line and nearer to the
CB .
• It is also one of the protective relay.
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3. What is
Auto – Reclosing ?
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4. Introduction to auto-reclosing scheme
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5. Types Of Faults
• Transient Faults
• Semi Permanent faults
• Permanent Faults
Utility Substation Customers
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6. 6
STEPS TO BE FOLLOWED IN AUTORECLOSING
Visual Check
Check of the
Power Supply
Test of the
Auto-re-closure settings
Functional Testing
(involving operation of
Protective Relays
& Circuit Breaker(s)
INSTALLATION
OPERATION

7. Scheme Of Operation
• Live bus Dead Line Charging
• Other end closing under synchronism check relay
• Live bus Live line charging
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8. Types of Auto Reclosing
1. Medium voltage auto-reclose
• Aim of continuity of supply
• the obvious advantages are continuous supply except for short
duration when tripping and re-closure operations are being performed.
• high speed protection decreases the amount of damage incurred and
thus increases the probability of auto reclosure.
2. High voltage auto-reclose
• main considerations are of stability and synchronizing.
• the fault levels associated are extremely high.
• High speed re-closure in high voltage circuits improves the stability
to a considerable extent on single-circuit ties.

9. FACTORS TO BE CONSIDERED FOR
AUTO RECLOSING SYSTEM
• Protection Characteristics
• De- Ionization of Fault Arc
• Circuit Breaker Characteristics
• Reclaim Time
• Number of Shots
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10. SINGLE PHASE AUTO – RECLOSING
ADVANTAGES:-
•Maintenance of System Integrity
• Reduced switching overvoltage due to reclosing
• Reduced shock to generators.
• Sudden changes in mechanical output are less
• Longer De – ionization time
DISADVANTAGE:-
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11. 1. Densely interconnected systems.

Where the Loss of a single line is unlikely to
cause loss of synchronism between two ends
2. Dead Time is allowed to be long enough for any
power swings due to fault and tripping allowed
to decay before reclosing

a) Less shock to system than with high speed
A/R
b) Problems of arc de – ionization times, and
circuit breaker operating characterstics are
eliminated.
Delayed Auto-Reclose Application
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12. Operating feature of Auto reclosing schemes
• Dead Timer
• Anti Pumping Devices
• Reclaim timer
• CB Lockout
• Manual Closing
• Multi Shot Scheme
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13. Auto - Reclose Blocking
• Receipt of transfer Trip
• Manual Trip
• Breaker failure
• Three phase Fault
• Faults On Buses
• Under frequency/ Under voltage load shedding trips
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14. Benefits Of Auto - Reclosing
• Minimizing the interruption of supply.
• Maintenance of system stability and Synchronism.
• Minimum Outage and least expenditure of manpower.
• Ability to run substation unattended.
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15. CONCLUSION
• Fast clearing of EHV faults is essential to
maintain power quality in an area, because
events on the EHV system affect the
underlying transmission and distribution
systems. Benefits of successful high speed
reclosing on EHV overhead transmission lines
are: improved system stability, reducing the
duration of fault arc, respectively disturbance
time, and economics in system design.
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16. Thank you
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