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.

LEGEND 1.X side terminal 2.Vacuum interrupter 3.Epoxy bushing 4.Earthing point 5.Stainless steel tank 6.Magnetic actuator 7.Scem card 8.Control cable 9.Manual trip ring 10.Pointer 11.Lightning arrester brackets 12.Stainless steel lid 13.Current transformer 14.Capacitive voltage transformer 15.I-side terminal

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

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