The Relay Enabled Front-Panel Led Is Dark; The Relay Front-Panel Display Does Not Show Characters; The Relay Does Not Accurately Measure Voltages Or Currents; Table 10.8 Troubleshooting - Sel 751A Instruction Manual

10.14 Testing and Troubleshooting
Troubleshooting
Table 10.7 Relay Self-Tests (Sheet 3 of 3)
Self-Test
Back-plane
comms diagnostics
CID File
Troubleshooting

Table 10.8 Troubleshooting

Symptom/Possible Cause

The relay ENABLED front-panel LED is dark.

Input power is not present or a fuse is blown.
Self-test failure

The relay front-panel display does not show characters.

The relay front-panel has timed out.
The relay is de-energized.

The relay does not accurately measure voltages or currents.

Wiring error
Incorrect CTR, CTRN, or PTR setting
Voltage neutral terminal (N) is not properly grounded.
The relay does not respond to commands from a device connected to the serial port.
Cable is not connected.
Cable is not the correct type.
The relay or device is at an incorrect baud rate or has another
parameter mismatch.
The relay serial port has received an XOFF, halting communi-
cations.
The relay does not respond to faults.
The relay is improperly set.
Improper test source settings
Current or voltage input wiring error
Failed relay self-test
SEL-751A Relay
Description
Fail if GPSB is busy on entry to process-
ing interval
Failure to Access/Read CID File
Instruction Manual
Protection
Normal Alarm
Disabled
Range Status
on Failure
Yes Latched
No N/A
Diagnosis/Solution
Verify that input power is present.
Check fuse continuity.
View the self-test failure message on the front-panel display.
Press the {ESC} pushbutton to activate the display.
Verify input power and fuse continuity.
Verify input wiring.
Verify instrument transformer ratios, connections, and associated
settings.
Verify wiring and connections.
Verify the cable connections.
Verify the cable pinout.
Verify Device software setup.
Type <Ctrl+Q> to send the relay XON and restart communica-
tions.
Verify the relay settings.
Verify the test source settings.
Verify input wiring.
Use the front-panel RELAY STATUS
results.
Front-Panel
Message
on Failure
Status Fail
GPSB Failure
Status Fail
CID File Failure
function to view self-test
Date Code 20100129