Sel 551 - Relay Self-Tests

8.16
SEL-551 Relay Instruction Manual Date Code 20110408
Testing and Troubleshooting
Relay Self-Tests
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 8.3):
➤ Protection Disabled: The relay disables overcurrent elements
and trip/close logic. All output contacts are de-energized. The
EN front-panel LED is extinguished.
➤ ALARM Output: The ALARM output contact signals an alarm
condition by going to its de-energized state. If the ALARM output
contact is a b-type output contact (normally closed), it closes
for an alarm condition or if the relay is de-energized. If the
ALARM output contact is an a-type output contact (normally
open), it opens for an alarm condition or if the relay is de-
energized. Alarm condition signaling can be five-second pulses
(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 8.3 Relay Self Tests (Sheet 1 of 2)
Self-Test Condition Limits
Protection
Disabled
ALARM Description
IA,IB,IC,IN
Offset
Warning 30 mV No Pulsed Measures the dc offset at each of the
current input channels every 0.2 seconds.
Master
Offset
Warning 20 mV No Pulsed Measures the dc offset
at the A/D every 0.2 seconds.
Failure 30 mV Yes Latched
+5V PS Warning +4.75 V
+5.25 V
No Pulsed Measures the +5 volt
power supply every 0.2 seconds.
Failure +4.70 V
+5.50 V
Yes Latched
±5V REG Warning ±4.65 V
±5.35 V
No Pulsed Measures the regulated 5 volt
power supply every 0.2 seconds.
Failure ±4.50 V
±5.50 V
Yes Latched
±10V PS Warning ±9.00 V
±11.00 V
No Pulsed Measures the 10 volt
power supply every 0.2 seconds.
Failure ±8.00 V
±12.00 V
Yes Latched
VBAT Warning +2.25 V
+5.00 V
No Pulsed Measures the Real Time
clock battery every 0.2 seconds.
Failure +2.10 V
+6.00 V
No Pulsed
TEMP Warning –40° C
+85° C
No Measures the temperature at the
A/D voltage reference every 0.2 seconds.
Failure –50° C
+100° C
Yes Latched