26-04-2011, 09:37 AM
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AUTOMATIC CIRCUIT RECLOSER
INTRODUCTION
Automatic circuit recloser is essentially a self contained device, which sense overcurrents to time and interrupt fault currents and to reenergize the line by reclosing automatically.
If fault is permanent ,recloser locks open after a preset no. of operations,isolating the faulted section from main part of the system.
Temporary faults
Tree branches touching energized lines
Lightning surges flashing over an insulator
Birds ,reptiles bridging between an energized line and agrounded surface.
Windblown conductors touching one another.
Recloser classifying features
Single phase or three phase.
Interrupters:oil or vacuum.
Insulation:oil,air or epoxy.
In three phase
(1)triple single tripping
(2)three phase tripping
Interrupting medium
Oil interrupters: recloser with hydraulic control use this interrupters.
Vacuum interrupters: it provide fast,low energy arc interruption with long contact and interrupter life
It is designed with a metal and ceramic housing for maximum strength.
Contact and interrupter life is larger than other interrupting madium .
Automatic circuit recloser
Controlling part of the recloser
Monitoring and control of the recloser is performed by PTCC,which is located lower down the pole.
It houses the operator control panel and microelectronics that provide the protection functions
It is connected to recloser by a detachable control cable.
Internal equipment panel is used to mount all the equipments.
The cubicle is insulated.
It incorporate the function of overcurrent protection relay,sensitive earth fault relay,reclose relay and a RTU.
Electronic measure line current,voltage,fault current.
Ptcc requires auxillary ac supply.
Recloser operation is independent of the high volt supply.
Block diagram of recloser working
Three level of user interface with operator control panel
Operator level
Technician level
Engineer level
Computer interface
The WSOS is an advanced personal computer based software package to allow off-line and on-line programming, monitoring and control of a recloser .
Recloser application
Location for recloser are:
in substations as the primary feeder protective device
On distribution lines at a distance from a substation,to sectionalize long feeders and thus prevent outages of the entire feeder when a permanent fault occurs near the end of the feeder
On important taps of main feeders to protect the main feeder from interruptions and outages due to faults on the taps.
Pole mounting detail
Advantages of automatic circuit recloser
Reduced purchase cost
Reduced installation cost
Reduced operating cost
Improved environmental aspects
Increased revenue
Disadvantages
Wiring connectors or recloser are required
Lightning arrestor are to be mounting
