Date Code 970103 Communications 3-29
SEL-251, -2, -3 Instruction Manual
TCG External Torque Control (Residual Overcurrent Elements)
!TCG (inverted sense of TCG)
52A Circuit Breaker Status (52A contact input)*
!52A Circuit Breaker Status (52B contact input)*
52AR Circuit Breaker Status (52A contact input)/Reclose Initiate*
!52AR Circuit Breaker Status (52B contact input)/Reclose Initiate*
DC Direct Close (requires circuit breaker status)
RE Reclose Enable (requires circuit breaker status)
TCM Trip Circuit Monitor (requires circuit breaker status)
ET External Trigger of Event Report
DT Direct Trip
(blank) Unassigned Input
Type NA <ENTER> to clear settings.
IN1 = SS1 ?
IN2 = DT ?
IN3 = RE ?
IN4 = ?
IN5 = 52A ?
IN6 = ?
* Only one of the circuit breaker status input options 52A, !52A, 52AR, or !52AR
should be assigned to an input.
52A or !52A
If 52A or !52A is assigned to an input, only circuit breaker status information is
provided. Reclose initiation is provided by the assertion of the internal TRIP
condition. When the TRIP condition drops out and the circuit breaker is open (per
52A or !52A), the open interval starts timing.
52AR or !52AR
If 52AR or !52AR is assigned to an input, not only does the input provide circuit
breaker status information, but it provides reclose initiation, too. The sensed
transition of the circuit breaker status, indicating that the circuit breaker is
opening, initiates reclosing. If the TRIP condition is present, it has to drop out
before the open interval starts timing.
In most applications, circuit breaker trips external to the relay (e.g., by control
switch or SCADA) must not cause reclose initiation. If input option RE (Reclose
Enable) is assigned to an input, the RE input is de-energized to prevent automatic
reclosing. Certain control switch contacts can be wired to the RE input to defeat
reclosing for control switch trips.
Also, if 52AR or !52AR is assigned to an input, the circuit breaker status function
is time delayed by 10 cycles to qualify circuit breaker opening. This is done for
certain application needs (see System Restoration After Underfrequency Load-
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