P.7.40
SEL-411L Relay Protection Manual Date Code 20151029
Front-Panel Operations
Operation and Target LEDs
➤ the channel is required but not synchronized
➤ the 87L protection is not available (lost)
Recloser and
Synchronizing Status
The 79 RESET, 79 LOCKOUT, and 79 CYCLE target LEDs show the operating status
of the reclosing function.
The 79 RESET LED indicates that the relay recloser is in the reset or ready-to-
reclose state for Circuit Breaker 1 (Relay Word bit BK1RS is asserted).
The 79 LOCKOUT target illuminates when the relay has completed the reclose
attempts unsuccessfully for Circuit Breaker 1 (a drive-to-lockout condition),
or when other programmed lockout conditions exist.
The 79 CYCLE target illuminates when the relay the relay is in the autoreclose
cycle state for Circuit Breaker 1.
The 25 SYNCH LED illuminates when the relay detects that the Circuit
Breaker 1 voltages are within Synchronism Angle 1 (Relay Word bit
25A1BK1 is asserted). See Synchronism Check on page P.4.49 for complete
details.
Instantaneous and
Time-Delayed
Overcurrent, LOP and
IRIG
The 50 target LED indicates that an instantaneous overcurrent element picked
up. These elements are the nondirectional 50Pn phase overcurrent elements,
50Qn negative-sequence overcurrent elements, and the 50Gn ground
overcurrent elements, where n is the overcurrent level; n = 1, 2, 3, and 4.
The 51 target LED illuminates if a time-overcurrent element has timed out.
The relay lights this LED if any of the selectable operating quantity inverse-
time overcurrent elements 51T01–51T10 assert.
The LOP LED illuminates when the relay detects a loss-of-potential condition
(Relay Word bit LOP is asserted). See Loss-of-Potential Logic on
page P.3.137 for complete details.
The IRIG LOCKED target LED illuminates when the relay detects
synchronization to an external clock with less than 500 ns of jitter (Relay
Word bit TIRIG is asserted). See IRIG-B on page P.13.1 for complete details.
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