10.14
SEL-751A Relay Instruction Manual Date Code 20100129
Testing and Troubleshooting
Troubleshooting
Troubleshooting
Back-plane
comms diagnostics
Fail if GPSB is busy on entry to process-
ing interval
Yes Latched
Status Fail
GPSB Failure
CID File Failure to Access/Read CID File No N/A Status Fail
CID File Failure
Table 10.7 Relay Self-Tests (Sheet 3 of 3)
Self-Test Description
Normal
Range
Protection
Disabled
on Failure
Alarm
Status
Front-Panel
Message
on Failure
Ta b le 1 0. 8 Tr ou bl e s hoo ti n g
Symptom/Possible Cause Diagnosis/Solution
The relay ENABLED front-panel LED is dark.
Input power is not present or a fuse is blown. Verify that input power is present.
Check fuse continuity.
Self-test failure View the self-test failure message on the front-panel display.
The relay front-panel display does not show characters.
The relay front-panel has timed out. Press the {ESC} pushbutton to activate the display.
The relay is de-energized. Verify input power and fuse continuity.
The relay does not accurately measure voltages or currents.
Wiring error Verify input wiring.
Incorrect CTR, CTRN, or PTR setting Verify instrument transformer ratios, connections, and associated
settings.
Voltage neutral terminal (N) is not properly grounded. Verify wiring and connections.
The relay does not respond to commands from a device connected to the serial port.
Cable is not connected. Verify the cable connections.
Cable is not the correct type. Verify the cable pinout.
The relay or device is at an incorrect baud rate or has another
parameter mismatch.
Verify Device software setup.
The relay serial port has received an XOFF, halting communi-
cations.
Type <Ctrl+Q> to send the relay XON and restart communica-
tions.
The relay does not respond to faults.
The relay is improperly set. Verify the relay settings.
Improper test source settings Verify the test source settings.
Current or voltage input wiring error Verify input wiring.
Failed relay self-test Use the front-panel
RELAY STATUS function to view self-test
results.
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