Date Code 20011205
Testing and Troubleshooting
13-43
SEL-311B Instruction Manual
Symptom:
What to check:
·
Verify the Loss-of-Potential (LOP) logic and element settings. If
ELOP = Y or Y1, the relay blocks operation of the distance
elements when LOP conditions are detected.
·
The Load-Encroachment function blocks operation of the relay
phase distance elements if measured positive-sequence impedance
is within a defined load characteristic. Verify your Load-
Encroachment logic settings and review event report data to
determine if this function is interfering with your phase distance
element test.
Incorrect Contact
Operation
·
Check the logic equation settings to determine which elements are
enabled to operate the contact.
·
Check the event report to determine which elements asserted during
the event.
·
Check the connections and test signals to ensure that the
appropriate signals were applied to cause the element under test to
assert.
R
ELAY
S
ELF
-T
ESTS
The relay runs a variety of self-tests. The relay takes the following corrective actions for out-of-
tolerance conditions (see Table 13.5):
·
Protection Disabled: The relay disables protection 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.
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