P.7.39
Date Code 20151029 Protection Manual SEL-411L Relay
Front-Panel Operations
Operation and Target LEDs
The COMM LED illuminates, indicating that tripping resulted from a
communications-assisted trip. The relay lights the COMM target when there is a
relay tripping condition and the Relay Word bit COMPRM (communications-
assisted trip permission) asserts.
The SOTF target LED indicates that the switch-onto-fault protection logic
operated. The relay illuminates the SOTF target when there is a relay tripping
condition and the Relay Word bit SOTFT (switch-onto-fault trip) asserts.
Zone Activated
The zone activated area target indicators are the ZONE 1, ZONE 2, ZONE 3, and
ZONE 4 LEDs. These targets illuminate when the corresponding zone distance
elements pick up and there is a relay tripping condition.
In factory default programming, the lowest zone LED has priority; only the
LED corresponding to the closest protection zone latches for distance element
pickups.
The ZONE 1 target illuminates if either the Z1P or Z1G distance elements
operated.
The ZONE 2 target illuminates if either the Z2P or Z2G distance elements
operated and the similar elements in Zone 1 did not operate.
The ZONE 3 target illuminates if either the Z3P or Z3G distance elements
operated and the similar elements in Zone 1 and Zone 2 did not operate.
The ZONE 4 target illuminates if either the Z4P or Z4G distance elements
operated and the similar elements in Zone 1, Zone 2, and Zone 3 did not
operate.
Phase(s) or Ground
The phase(s) or ground targets illuminate according to the relay special
targeting logic. This logic accurately classifies which phase, phases, and/or
ground were involved in a trip event.
The PHASE A target LED lights for faults on the power system A-phase.
Single-phase-to-ground faults from A-phase to ground illuminate both the
PHASE A and GROUND targets. A phase-to-phase fault between A-phase and
B-phase illuminates the PHASE A target and the PHASE B target.
The relay displays faults involving other phase combinations similarly. If the
phase-to-phase fault includes ground, the relay also lights the GROUND target.
The relay lights the PHASE A, PHASE B, and PHASE C target LEDS for a three-
phase fault.
Current Differential
Protection
Information
This LED illuminates when the line current differential protection operated
and includes indication of phase, ground, and negative-sequence differential
elements, as well as the 87 Direct Transfer Trip. The LED also illuminates
when the 87L function is not available (lost); the relay is not in the master
mode and will not trip via 87 DTT because the DTT is disabled, or none of the
connected relays is in the master mode. Lastly, the LED illuminates when
there is a channel alarm condition. Channel alarm conditions include:
➤ the channel is not OK for 0.5s (drop out, wrong relay ID,
wrong firmware ID)
➤ the lost packet alarm is asserted
➤ the channel delay time is exceeded
➤ channel asymmetry is exceeded while the channel is required
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