Schweitzer Engineering Laboratories SEL-351 - Relay Self-Tests

13-6 Testing and Troubleshooting Date Code 20001006
SEL-351 Instruction Manual
To test the phase time-overcurrent element 51PT with the SER, make the following setting:
SER1 = 51P 51PT
Element 51P asserts when phase current is above the pickup of the phase time-overcurrent
element. Element 51PT asserts when the phase time-overcurrent element times out. The
assertion and deassertion of these elements is time-stamped in the SER report. Use this method
to verify timing associated with time-overcurrent elements, reclosing relay operation, etc. Do not
forget to reenter the correct relay settings when you are ready to place the relay in service.
RELAY SELF-TESTS
The relay runs a variety of self-tests. The relay takes the following corrective actions for out-of-
tolerance conditions (see Table 13.1):
• Protection Disabled: The relay disables overcurrent elements and trip/close logic. All
output contacts are deenergized. The EN front-panel LED is extinguished.
• ALARM Output: The ALARM output contact signals an alarm condition by going to its
deenergized state. If the ALARM output contact is a B contact (normally closed), it
closes for an alarm condition or if the relay is deenergized. If the ALARM output contact
is an A contact (normally open), it opens for an alarm condition or if the relay is
deenergized. Alarm condition signaling can be a single 5-second pulse (Pulsed) or
permanent (Latched).
• The relay generates automatic STATUS reports at the serial port for warnings and
failures.
• The relay displays failure messages on the relay LCD display for failures.
Use the serial port STATUS command or front-panel STATUS pushbutton to view relay self-test
status.
Table 13.1: Relay Self-Tests
Self-Test Condition Limits
Protection
Disabled
ALARM
Output Description
IA, IB, IC,
IN, VA, VB,
VC, VS
Offset
Warning 30 mV No Pulsed Measures the dc offset at
each of the input
channels every 10
seconds.
Master
Offset
Warning 20 mV No Pulsed Measures the dc offset at
the A/D every 10
seconds.
Failure 30 mV Yes Latched
+5 V PS Warning +4.80 V
+5.20 V
No Pulsed Measures the +5 V power
supply every 10 seconds.
Failure +4.65 V
+5.40 V
Yes Latched
Courtesy of NationalSwitchgear.com