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10.20
SEL-400 Series Relays
Instruction Manual
Date Code 20171006
Testing, Troubleshooting, and Maintenance
Relay Troubleshooting
PT or CT connection wiring error.
Confirm PT and CT wiring.
Input voltages and currents phasing,
and rotation errors.
Use relay metering. Use the
TRI
event trigger command and examine the generated event
Examining Metering Quantities on page 3.35
The analog input (flat multipin ribbon)
cable between the input module board
and the main board is loose or defective.
Reseat both ends of the analog input cable, observing proper ESD precautions (see
Optional I/O Interface Boards on page 10.24
Check the relay self-test status.
Take preventive action as directed by relay Status Warning and Status Failure information (see
Checking Relay Status on page 3.11
Sequence of Events Recorder
SER DATA LOSS Reported
This is caused by an internal buffer overrun, which can occur if SER points are being triggered
faster than they can be processed. It will recover as soon as the SER processing can catch up.
SER data loss can also be caused by excessive SER triggering (>6000 points per hour), causing
the relay to temporarily suspend storing points. In this case, it will normally recover within an
hour, but the SER DATA LOSS END message will not be reported until the first SER point is
triggered after the suspension ends.
Tripping Output Relay Remains Closed Following a Fault
Auxiliary contact control inputs are
improperly wired.
Check circuit breaker auxiliary contacts wiring.
Control output relay contacts have
burned closed.
Remove relay power. Remove the control output connection. Check continuity—Form A con-
tacts should be open and Form B contacts should be closed. Contact the SEL factory or your
Technical Service Center if continuity checks fail.
I/O interface board failure.
LCD displays
STATUS FAILURE
screen. Contact the SEL factory or your Technical Service Center.
Time/Date Errors
External IRIG time source error.
Check IRIG-B time source or cables. Check
TIME Q
command or
HMI SET/SHOW | Date/
Time
screen.
A low-priority time source error.
Check last update source (
TIME Q
command or
HMI SET/SHOW | Date/Time
screen) (see
Lithium clock battery failure.
Verify that the battery has failed before replacing the battery–it should last for 10 years if the
relay is energized (see
Replacing the Lithium Battery on page 10.22
).
TiDL Applications
Relay will not successfully commis-
sion.
Check the configuration of axion CT/PT modules and verify that they match a supported topol-
ogy (see
Section 2: Installation
in the product-specific instruction manual).
Relay disabled.
Check the CT/PT modules for failure. If a module is identified as failed, replace the CT/PT
module and then press the commissioning button on the back of the relay (see
Table 10.7
Troubleshooting for Relay Self-Test Warnings and Failures (Sheet 1 of 2)
Diagnostic Message
Diagnosis/Solution
Memory Failures
RAM Failure
a
This indicates a failure of a memory device. Contact the SEL factory or your Technical Service
Center.
Flash Failure
Settings Failed
Default Settings Failure
Default Cal Settings
This indicates that something has occurred that has caused the relay to lose its calibration. Con-
tact the SEL factory or your Technical Service Center.
Table 10.6
Troubleshooting Procedures (Sheet 2 of 2)
Symptom/Cause
Diagnosis/Solution
Summary of Contents for SEL-421-4
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