Schweitzer Engineering Laboratories SEL-421-4 - Table 4.3 TIME Target LED Trigger Elements-Factory Defaults

4.11
Date Code 20171021 Instruction Manual SEL-421 Relay
Front-Panel Operations
Target L EDs
The COMM LED illuminates, indicating that tripping resulted from a communica-
tions-assisted trip. The relay lights the COMM target when there is a relay tripping
condition and the Relay Word bit COMPRM (communications-assisted trip per-
mission) asserts.
The SOTF target LED indicates that the switch-onto-fault protection logic oper-
ated. 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 or if the high-speed Zone 1 elements operated.
The ZONE 2 target illuminates if either the Z2P or Z2G distance elements
operated or if the high-speed Zone 2 elements operated and the similar ele-
ments in Zone 1 did not operate.
The ZONE 3 target illuminates if either the Z3P or Z3G distance elements
operated or if the high-speed Zone 3 elements operated and the similar ele-
ments 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 SEL-421 special tar-
geting 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 illumi-
nates 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.
Ta b l e 4. 3 TIME Ta r g e t L E D Trig ge r E l e m ents— Fa c tor y D ef a u l t s
Mho Quadrilateral
M2PT Z2GT
M3PT Z3GT
M4PT Z4GT
M5PT Z5GT