10.11
Date Code 20150130 Instruction Manual SEL-787 Relay
Testing and Troubleshooting
Self-Test
Self-Test
The SEL-787 runs a variety of self-tests. The relay takes the following
corrective actions for out-of-tolerance conditions (see Table 10.8):
➤ Protection Disabled: The relay disables protection and control
elements and trip/close logic. All output contacts are
deenergized. 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 changes, copy commands, and
password changes. HALARM is pulsed for hardware self-test
warnings. HALARM is continuously asserted (set to logical 1)
for hardware self-test failures. A diagnostic alarm may be
configured as explained in Section 4: Protection and Logic
Functions. In the Alarm Status column of Table 10.8, 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 LCD display for
failures.
➤ For certain failures, the relay will automatically restart as many
as three times. In many instances, this will correct the failure.
The failure message might not be fully displayed before
automatic restart occurs. Indication that the relay restarted will
be recorded in the Sequential Events Recorder (SER).
Use the serial port STATUS command or 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.
Table 1 0.8 Rel ay Self-Test s (Sheet 1 of 4)
Self-Test Description
Normal
Range
Protection
Disabled
on Failure
Alarm
Status
Auto
Message
on Failure
Front Panel
Message
on Failure
Corrective
Action
Watchdog Timer Periodic resetting
(1/32 cycle)
Yes
De-
energized
No No
Mainboard FPGA (power up)
Fail if mainboard Field Programmable
Gate Array does not accept program or
the version number is incorrect
Yes Latched Yes Status Fail
FPGA Failure
Automatic restart.
Contact SEL if
failure returns.
Mainboard FPGA (run time)
Fail on lack of data acquisition interrupts
or on detection of a CRC error in the
FPGA code
Yes Latched Yes Status Fail
FPGA Failure
Automatic restart.
Contact SEL if
failure returns.
GPSB (back-plane) communications
Fail if GPSB is busy on entry to
processing interval
Yes Latched Yes Status Fail
GPSB Failure
STA C, to clear
the warning in the
status report.
Contact SEL if
failure returns.
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