Date Code 20010625
Close and Reclose Logic
6-19
SEL-311L Instruction Manual
SEL
OGIC
Control
Equation Setting
Setting
Definition
79SKP 0
Skip
Shot
79STL
TRIP
Stall Open Interval Timing
79BRS
0
Block Reset Timing
79SEQ 0
Sequence
Coordination
79CLS 1
Reclose
Supervision
These example settings are discussed in detail in the remainder of this subsection.
Reclose Initiate and Reclose Initiate Supervision Settings (79RI and 79RIS,
Respectively)
The reclose initiate setting 79RI is a rising-edge detect setting. The reclose initiate supervision
setting 79RIS supervises setting 79RI. When setting 79RI senses a rising edge (logical 0 to
logical 1 transition), setting 79RIS has to be at logical 1 (79RIS = logical 1) in order for open
interval timing to be initiated.
If 79RIS = logical 0 when setting 79RI senses a rising edge (logical 0 to logical 1 transition), the
relay goes to the Lockout State.
Settings Example
With settings:
79RI
= TRIP + TRIP87
79RIS
= 52A + 79CY
the transition of the TRIP or TRIP87 Relay Word bit from logical 0 to logical 1 initiates open
interval timing only if the 52A + 79CY Relay Word bit is at logical 1 (52A = logical 1, or 79CY
= logical 1). Input IN101 is assigned as the breaker status input in the factory settings (52A =
IN101).
The circuit breaker has to be closed (circuit breaker status 52A = logical 1) at the instant of the
first trip of the auto-reclose cycle in order for the SEL-311L Relay to successfully initiate
reclosing and start timing on the first open interval. The SEL-311L Relay is not yet in the
reclose cycle state (79CY = logical 0) at the instant of the first trip.
Then for any subsequent trip operations in the auto-reclose cycle, the SEL-311L Relay is in the
reclose cycle state (79CY = logical 1) and the SEL-311L Relay successfully initiates reclosing
for each trip. Because of setting 79RIS = 52A + 79CY, successful reclose initiation in the
reclose cycle state (79CY = logical 1) is not dependent on the circuit breaker status (52A). This
allows successful reclose initiation for the case of an instantaneous trip, but the circuit breaker
status indication is slow—the instantaneous trip (reclose initiation) occurs before the SEL-311L
Relay sees the circuit breaker close.
If a flashover occurs in a circuit breaker tank during an open interval (circuit breaker open and
the SEL-311L Relay calls for a trip), the SEL-311L Relay goes immediately to lockout.
Summary of Contents for SEL-311L
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