10.14
SEL-787 Relay
Instruction Manual
Date Code 20081022
Testing and Troubleshooting
Troubleshooting
Troubleshooting
Factory Assistance
We appreciate your interest in SEL products and services. If you have
questions or comments, please contact us at:
Schweitzer Engineering Laboratories, Inc.
2350 NE Hopkins Court
Pullman, WA 99163-5603 USA
Tel: +1.509.332.1890
Fax: +1.509.332.7990
Internet: www.selinc.com or www.selindustrial.com
Email: info@selinc.com
Table 10.9
Troubleshooting
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 CTR1, CTR2, 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
communications.
Type
<Ctrl+Q>
to send the relay XON and restart communications.
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.
Summary of Contents for SEL-787
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