11.13
Date Code 20170927 Instruction Manual SEL-751 Relay
Testing and Troubleshooting
Self-Test
Self-Test
The SEL-751 runs a variety of self-tests. The relay takes the following
corrective actions for out-of-tolerance conditions (see Table 11.8):
➤ Protection Disabled: The relay disables protection and control
elements and trip/close logic. All output contacts are de-
energized. The ENABLED front-panel LED is extinguished.
➤ ALARM Output: Two Relay Word bits, HALARM and
SALARM, signal self-test problems. SALARM is pulsed for
software programmed conditions, such as settings changes,
access level changes, three consecutive unsuccessful password
entry attempts, active group change, copy command, and
password change. HALARM is pulsed for hardware self-test
warnings. HALARM is continuously asserted (set to logical 1)
for hardware self-test failures. A diagnostic alarm can be
configured as explained in Section 4: Protection and Logic
Functions. In the Alarm Status column of Table 11.8, Latched
indicates that HALARM is continuously asserted, Not Latched
indicates that HALARM is pulsed for five seconds, and NA
indicates that HALARM is not asserted.
➤ The relay generates automatic STATUS reports at the serial
port for warnings and failures (ports with setting AUTO = Y).
➤ The relay displays failure messages on the relay front-panel
display for failures.
➤ For certain failures, the relay automatically restarts as many as
three times. In many instances, this corrects the failure. The
failure message might not be fully displayed before automatic
restart occurs. An indication that the relay restarted is recorded
in the Sequential Events Recorder (SER).
Use the serial port STATUS command or the front panel to view relay self-test
status. Based on the self-test type, issue the STA C command as directed in
the Corrective Actions column. Contact SEL if this does not correct the problem.
Control Input Using the front-panel MAIN > Targets > Row 17 function, check
the control input status in the relay. As you apply rated voltage to each
input, the position in Row 17 corresponding to that input should change
from zero (0) to one (1).
Contact Out-
put
Program each of the output contacts you want to test to logical 1. This
causes the output contact to close. For example, setting OUT101 := 1
causes the output OUT101 contact to close.
Make sure that each contact closure does what you want it to do in the
annunciation, control, or trip circuit associated with that contact closure.
Table 11.7 Periodic Relay Checks (Sheet 2 of 2)
Test Description
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