Date Code 20020129
Control Logic
4-13
SEL-387E Instruction Manual
R
OTATING
D
EFAULT
D
ISPLAY
The rotating default display on the relay front panel replaces indicating panel lights. Traditional
indicating panel lights are turned on and off by circuit breaker auxiliary contacts, front-panel
switches, SCADA contacts, etc. See
Section 8: Front-Panel Interface
for details.
LED T
ARGETING
L
OGIC
The SEL-387E Relay has 16 LEDs on the front panel. One (EN) is dedicated to indication of the
relay’s operational condition. Twelve are dedicated to specific targeting functions. Three
(LEDA, LEDB, and LEDC) have default targeting logic, but are fully programmable by the user.
The states of the 12 dedicated LEDs (all but EN, A, B, C) are stored in nonvolatile memory. If
power is lost to the relay, these 12 targets will be restored to their last state when the relay power
is restored. EN responds only to internal self-test routines, while A, B, and C respond to the
present state of their respective Global SEL
OGIC
control equation settings.
The array of LEDs is shown below in Figure 4.6.
Figure 4.6: SEL-387E Relay Front-Panel LEDs
Table 4.5 describes the basic targeting functions associated with each of the 16 LEDs.
Table 4.5: LED Assignments
LED Legend
Description
1 EN Relay
enabled
2 TRIP*
Relay
trip
3 INST*
Instantaneous
trip
4
87-1*
Differential element 1 asserted at, or 1 cycle after, rising edge of trip
5
87-2*
Differential element 2 asserted at, or 1 cycle after, rising edge of trip
6
87-3*
Differential element 3 asserted at, or 1 cycle after, rising edge of trip
7
81*
O/U frequency element asserted at, or 1 cycle after, rising edge of trip
8
24*
Volts/hertz element asserted at, or 1 cycle after, rising edge of trip
9
A
A-phase involved in the fault (Programmable LEDA)