5.31
Date Code 20060320 Instruction Manual SEL-311C Relay
Trip and Target Logic
Front-Panel Target LEDs
Front-Panel Target LEDs
Target LEDs numbered 2–5 and 8–16 in Table 5.1 are updated and then
latched for every new assertion (rising edge) of the TRIP Relay Word bit. The
TRIP Relay Word bit is the output of the backup protection trip logic (see
Figure 5.1).
Further target LED information follows. Refer also to Figure 2.2 through
Figure 2.7 for the placement of the target LEDs on the front panel.
Additional Target
LED Information
TRIP Target LED
The TRIP target LED illuminates at the rising edge of Trip (the new assertion
of the TRIP Relay Word bit).
The TRIP target LED is especially helpful in providing front-panel indication
for tripping that does not involve protection elements. If the trip is not a
protection element generated trip, none of the target LEDs illuminate (3–5 and
8–16), but the TRIP target LED still illuminates. Thus, tripping via the front-
panel local control (local bits), serial port (remote bits or OPEN command),
or voltage elements is indicated only by the illumination of the TRIP target
LED.
Table 5.1 SEL-311C Front-Panel Target LED Definitions
LED
Number
LED
Label
Definition
1 EN Relay Enabled—see Relay Self-Tests on page 13.58.
2 TRIP Indication that a trip occurred, by a protection or control element
3 TIME Time-delayed trip
4 COMM Communications-assisted trip
5 SOTF Switch-onto-fault trip
6 RS Recloser reset
7 LO Recloser locked out
8 51 Time-overcurrent element trip
9 A Phase A involved in the fault
10 B Phase B involved in the fault
11 C Phase C involved in the fault
12 G Ground distance
or residual ground element picked up at time of trip
13 1 Zone/Level 1 element picked up at time of trip
14 2 Zone/Level 2 element picked up at time of trip
15 3 Zone/Level 3 element picked up at time of trip
16 4 Zone/Level 4 element picked up at time of trip
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