GE Multilin C60 Instruction Manual Download Page 289

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GE Multilin

C60 Breaker Protection System

5-161

5 SETTINGS

5.7 CONTROL ELEMENTS

There are three initiate programs: single pole initiate, three pole initiate and three pole, time delay initiate. Any of these
reclose initiate signals will start the reclose cycle and set the reclose-in-progress (

AR RIP

) operand. The reclose-in-progress

operand is sealed-in until the Lockout or Reset signal appears.

The three-pole initiate and three-pole time delay initiate signals are latched until the

CLOSE BKR1 OR BKR2

or Lockout or

Reset signal appears.

AR PAUSE:

The pause input offers the possibility of freezing the autoreclose cycle until the pause signal disappears. This may be done
when a trip occurs and simultaneously or previously, some conditions are detected such as out-of step or loss of guard fre-
quency, or a remote transfer trip signal is received. The pause signal blocks all three dead timers. When the ‘pause’ signal
disappears the autoreclose cycle is resumed by initiating

AR 3-P DEAD TIME 2

This feature can be also used when a transformer is tapped from the protected line and a reclose is not desirable until the
transformer is removed from the line. In this case, the reclose scheme is ‘paused’ until the transformer is disconnected. The

AR PAUSE

input will force a three-pole trip through the

3-P DEADTIME 2

path.

EVOLVING FAULTS:

1.25 cycles after the single pole dead time has been initiated, the

AR FORCE 3P TRIP

operand is set and it will be reset only

when the scheme is reset or goes to Lockout. This will ensure that when a fault on one phase evolves to include another
phase during the single pole dead time of the auto-recloser the scheme will force a 3 pole trip and reclose.

RECLOSING SCHEME OPERATION FOR ONE BREAKER:

•

Permanent Fault

: Consider Mode 1, which calls for 1-Pole or 3-Pole Time Delay 1 for the first reclosure and 3-Pole

Time Delay 2 for the second reclosure, and assume a permanent fault on the line. Also assume the scheme is in the
Reset state. For the first single-phase fault the

AR 1-P DEAD TIME

timer will be started, while for the first multi-phase fault

the

AR 3-P DEAD TIME 1

timer will be started. If the

AR 3P TD INIT

signal is high, the

AR 3-P DEAD TIME 2

will be started for

the first shot.

AR MAX NO OF SHOTS

is set to “1”, upon the first reclose the shot counter is set to 1. Upon reclosing, the fault is again

detected by protection and reclose is initiated. The breaker is tripped three-pole through the

AR SHOT COUNT >0

oper-

and that will set the

AR FORCE 3P

operand. Because the shot counter has reached the maximum number of shots per-

mitted the scheme is sent to the Lockout state.

AR MAX NO OF SHOTS

is set to “2”, upon the first reclose the shot counter is set to 1. Upon reclosing, the fault is again

detected by protection and reclose is initiated. The breaker is tripped three-pole through the

AR SHOT COUNT >0

oper-

and that will set the

AR FORCE 3P

operand. After the second reclose the shot counter is set to 2. Upon reclosing, the

fault is again detected by protection, the breaker is tripped three-pole, and reclose is initiated again. Because the shot
counter has reached the maximum number of shots permitted the scheme is sent to the lockout state.

•

Transient Fault

: When a reclose output signal is sent to close the breaker the reset timer is started. If the reclosure

sequence is successful (there is no initiating signal and the breaker is closed) the reset timer will time out returning the
scheme to the reset state with the shot counter set to "0" making it ready for a new reclose cycle.

RECLOSING SCHEME OPERATION FOR TWO BREAKERS:

•

Permanent Fault

: The general method of operation is the same as that outlined for the one breaker applications

except for the following description, which assumes

AR BKR SEQUENCE

is “1-2” (reclose Breaker 1 before Breaker 2)

The signal output from the dead time timers passes through the breaker selection logic to initiate reclosing of Breaker
1. The Close Breaker 1 signal will initiate the Transfer Timer. After the reclose of the first breaker the fault is again
detected by the protection, the breaker is tripped three pole and the autoreclose scheme is initiated. The Initiate signal
will stop the transfer timer. After the 3-P dead time times out the Close Breaker 1 signal will close first breaker again
and will start the transfer timer. Since the fault is permanent the protection will trip again initiating the autoreclose
scheme that will be sent to Lockout by the

SHOT COUNT = MAX

signal.

•

Transient Fault

: When the first reclose output signal is sent to close Breaker 1, the reset timer is started. The close

Breaker 1 signal initiates the transfer timer that times out and sends the close signal to the second breaker. If the reclo-
sure sequence is successful (both breakers closed and there is no initiating signal) the reset timer will time out, return-
ing the scheme to the reset state with the shot counter set to 0. The scheme will be ready for a new reclose cycle.