Schweitzer Engineering Laboratories SEL-421-4 - Table 4.2 Front-Panel Target Leds; Figure 4.9 Factory-Default Front-Panel Target Areas (16 or 24 Leds)

4.10
SEL-421 Relay Instruction Manual Date Code 20171021
Front-Panel Operations
Target LEDs
Figure 4.9 shows the arrangement of the operation and target LEDs region into
several areas described in Table 4.2.
Trip Type
The SEL-421 indicates essential information about the most recent relay trip
event with the LEDs of the Trip Type area. These trip types are INST, TIME, COMM,
and SOTF. For information on setting the corresponding trip logic, see Trip Logic
on page 5.137.
The INST target LED illuminates, indicating operation of the SEL-421 instanta-
neous elements. This LED lights if elements Z1P (the Zone 1 mho phase-distance
element) or Z1G (the Zone 1 mho ground-distance element) pick up and the relay
has not illuminated the COMM or SOTF targets.
The TIME target LED indicates that a timed relay element caused a relay trip.
Table 4.3 lists the elements that activate the TIME LED in the factory-default set-
tings.
Figure 4.9 Factory-Default Front-Panel Target Areas (16 or 24 LEDs)
Ta b l e 4. 2 Fro n t - Pa n e l Ta rg et LEDs
Label Function
ENABLED, TRIP Operational
INST, TIME, COMM, SOTF Trip Type
ZONE 1, ZONE 2, ZONE 3, ZONE 4 Zone Activated
PHASE A, PHASE B, PHASE C, GROUND Phase(s) or Ground
50, 51 Instantaneous and Time-Delayed Overcurrent
79 RESET, 79 LOCKOUT, 79 CYCLE
a
a
Only available in 24 LED models.
Recloser Status
25 SYNCH
a
, BKR CLOSE
a
, BKR FAIL
a
, OSB
a
, LOP
a
Miscellaneous Status
PMCU OK
a
, IRIG LOCKED
a
Synchrophasor Status
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
(15)
(16)
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
(15)
(16)
(17)
(18)
(19)
(20)
(21)
(22)
(23)
(24)