U.6.39
Date Code 20090715 User’s Guide SEL-421 Relay
Testing and Troubleshooting
Relay Self-Tests
disabled state, the relay suspends protection element processing and trip/close
logic processing and deenergizes all control outputs. When disabled, the
ENABLED front-panel LED is not illuminated.
The relay signals a status warning by pulsing the HALARM Relay Word bit
(hardware alarm) to logical 1 for five seconds. For a Status Failure, the relay
latches the HALARM Relay Word bit at logical 1. SEL-421 relays will restart
on certain diagnostic failures. When this occurs, the relay will log a
Diagnostic Restart in the SER, and the HALARM Relay Word bit will
assert for five seconds. See Appendix A: Firmware and Manual Versions for
affected firmware revisions. To provide remote status indication, connect the b
contact of OUT108 to your control system remote alarm input and program
the output SEL
OGIC control equation to respond to NOT (SALARM OR
HALARM). See Alarm Output on page U.2.43 on connecting this alarm
output for the SEL-421.
If you repeatedly receive status warnings, check the relay operating conditions
as soon as possible. Take preventive action early during the development of
potential problems to avoid system failures. For any status failure, contact
your Technical Service Center or the SEL factory immediately (see Factory
Assistance on page U.6.45).
The relay generates an automatic status report at the serial ports for a self-test
status failure if you set Port setting AUTO := Y. The relay issues a status
message with a format identical to the STATUS command output (see Status),
except that the power supply information from the STA A response is
included after the SEL
OGIC control equation error messages.
The relay also displays status warning and status failure automatic messages
on the front-panel LCD. Use the serial port STATUS and CSTATUS
commands, the
ACSELERATOR QuickSet HMI Status button, and the front-
panel
RELAY STATUS menu to display status warnings and status failures. See
STATUS on page R.9.48, Checking Relay Status on page U.4.10, and Relay
Status on page U.5.32 for more information on automatic status notifications
and on viewing relay status.
Status
Figure 6.31 is a sample STATUS screen from the Status option of the
ACSELERATOR QuickSet HMI > Meter and Control tree view (the terminal
STATUS report is similar). Figure 6.32 is the STATUS A report showing all
status information on a terminal.
Firmware Version Number
At the top of each status report the relay displays the present firmware version
number that identifies the software program that controls relay functions. The
firmware version is the four-place designator immediately following the relay
model number (the first characters in the firmware identification string). The
first character in the four-place firmware version number is R (representing
Release).
For example, in Figure 6.31 and Figure 6.32, the firmware version number is
R101. SEL numbers subsequent firmware releases sequentially; the next
revision following R101 is R102. See Appendix A: Firmware and Manual
Versions for firmware version information.
Courtesy of NationalSwitchgear.com
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