5.34
SEL-351S Relay Instruction Manual Date Code 20080103
Trip and Target Logic
Front-Panel Target LEDs
Correlation between
Trip Target LEDs and
Trip Settings
Refer to subsection Trip Logic on page 5.1 and Ta ble 5.1.
The SEL
OGIC control equation factory-default trip setting is:
TR = 51P1T + 51G1T + 67P1 + PB10 + OC
NOTE: PB10 does not appear in the
TR equation for 0351Sxxx5/6/A/B
models.
LED12 (TRIP)
If a trip comes via PB10 (front-panel {TRIP} operator control—see
Figure 11.9) or OC (serial port OPEN command—see OPE Command (Open
Breaker) on page 10.39), no unique LED illuminates, just LED12 (TRIP):
➤ LED12 = TRIP
LED12 (TRIP) illuminates for every trip routed through the trip logic in
Figure 5.1.
LED13 (INST)
The following SELOGIC control equation settings are involved with LED13
(INST):
➤ FAULT = 51P1 + 51G1 (the corresponding pickup indicators
for time-overcurrent tripping elements 51P1T and 51G1T—see
Section 3: Overcurrent, Voltage, Synchronism Check,
Frequency, and Power Elements)
➤ SV1 = FAULT (run FAULT through a SV1PU = 3 cycle
timer—see Figure 7.24)
➤ LED13 = FAULT*!SV1T (= FAULT * NOT[SV1T])
LED13 (INST) illuminates at the rising edge of trip if the time-overcurrent
element pickup indicators have been picked up for less than 3 cycles.
SEL
OGIC control equation setting FAULT also controls other relay functions.
See subsection SEL
OGIC Control Equation Setting FAULT on page 5.37.
LED14 (COMM) and LED15 (SOTF)
Refer to the top part of Figure 5.1. If overcurrent elements are set in SELOGIC
control equations TRCOMM or TRSOTF and a trip results from either
associated logic path:
➤ Relay Word bit COMMT asserts (LED14 = COMMT)
➤ Relay Word bit SOTFT asserts (LED15 = SOTFT)
then LED14 (COMM) or LED15 (SOTF) illuminates at the rising edge of trip. No
overcurrent elements are set in TRCOMM or TRSOTF in the factory-default
settings, thus these two target LEDs are always extinguished with factory-
default settings.
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