10.19
Date Code 20171006 Instruction Manual SEL-400 Series Relays
Testing, Troubleshooting, and Maintenance
Relay Troubleshooting
Troubleshooting Procedures
Troubleshooting procedures for common problems are listed in Table 10.6 and
Table 10.7. The table lists each symptom, possible causes, and corresponding
diagnoses/solutions. Related ASCII commands are listed in bold capitals. See
Section 14: ASCII Command Reference for details on SEL-400 series commands
and Section 12: Settings for details on relay settings.
Table 10.6 Troubleshooting Procedures (Sheet 1 of 2)
Symptom/Cause Diagnosis/Solution
Dark Front Panel
Power is off. Verify that substation battery power is operational.
Input power is not present. Verify that power is present at the rear-panel terminal strip.
Blown power supply fuse. Replace the fuse (see Power Supply Fuse Replacement on page 10.23).
Poor HMI contrast. Press and hold ESC for two seconds. Press Up Arrow and Down Arrow pushbuttons to adjust contrast.
Status Failure Notice on Front Panel
Self-test failure. See Table 10.7 for guidance on the specific failure type.
The OUT108 relay control output b contacts will be closed if you programmed NOT HALARM
to OUT108.
Alarm Output Asserts
Power is off. Restore power.
Blown power supply fuse. Replace the fuse (see Power Supply Fuse Replacement on page 10.23).
Power supply failure. LCD displays STATUS FAILURE screen. See Table 10.7.
Main board or interface board failure. LCD displays
STATUS FAILURE screen. See Table 10.7.
Other self-test failure. LCD displays
STATUS FAILURE screen. See Table 10.7.
System Does Not Respond to Commands
NOTE: If Port setting PROTO := PMU, that serial port will not respond to ASCII commands. Additionally, a PROTO := PMU port will not respond to any
messages when Global setting EPMU := N.
No communication. Confirm cable connections and types. If correct, type <Ctrl+X> <Enter>. This resets the termi-
nal program.
Communications device is not con-
nected to the system.
Connect a communications device.
Incorrect data speed (baud rate) or
other communications parameters.
Configure your terminal port parameters to the particular relay port settings. Use the front panel
to check port settings (see Set/Show on page 4.25).
Incorrect communications cables. Use SEL communications cables, or cables you build according to SEL specifications (see
Serial Communication on page 15.2).
Communications cabling error. Check cable connections.
Handshake line conflict; system is
attempting to transmit information, but
cannot do so.
Check communications cabling. Use SEL communications cables, or cables you build accord-
ing to SEL specifications (see Serial Communication on page 15.2).
System is in the XOFF state, halting
communications.
Type <Ctrl+Q> to put the system in the XON state.
Terminal Displays Meaningless Characters
Data speed (baud rate) is set incorrectly. Check the terminal parameters configuration (see Serial Communication on page 15.2).
Terminal emulation is not optimal. Try other terminal types, including VT-100 and VT-52 terminal emulations.
System Does Not Respond to Faults
Relay is set improperly. Review the relay settings.
Improper test settings. Restore operating settings.
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