Sel 551 - Page 181

8.3
Date Code 20110408 Instruction Manual SEL-551 Relay
Testing and Troubleshooting
Testing Methods and Tools
Step 3. Monitor element pickup and dropout by observing the target
LEDs.
For example, the level 1 phase instantaneous overcurrent
element 50P1 appears in Relay Word Row 2. When you type
the command TAR 2 <Enter>, the terminal displays the labels
and status for each bit in the Relay Word Row (2) and the LEDs
display their status. Thus, with these new targets displayed, if
the level 1 phase instantaneous overcurrent element (50P1)
asserts, the fifth from the left LED illuminates. See Section 4:
Setting the Relay for a list of all Relay Word elements.
Step 4. Be sure to reset the front-panel targets to the default targets
after testing before returning the relay to service.
This can be done by pressing the front-panel {TARGET RESET}
pushbutton, or by issuing the TAR R command from the serial
port.
Output Contact Operation
Step 1. To test using this method, set one programmable output contact
to assert when the element under test picks up.
Step 2. With the SET L n command, enter the Relay Word bit name of
the element under test.
Step 3. For an a-type output contact, when the condition asserts, the
output contact closes. When the condition deasserts, the output
contact opens.
Step 4. For a b-type output contact, when the condition asserts, the
output contact opens. When the condition deasserts, the output
contact closes.
Programmable contacts can be changed to a- or b-type output contacts with a
solder jumper.
Step 1. Refer to Section 2: Installation for jumper locations.
Step 2. Using output contact operation as an indicator, you can
measure element operating characteristics, stop timers, etc.
Tests in this section assume an a-type output contact.
Sequential Event Recorder (SER)
Step 1. To test using this method, set the SER to trigger for the element
under test.
Step 2. With the SET R command, put the element name in the SER1,
SER2, or SER3 setting.
Whenever an element asserts or deasserts, a time stamp is
recorded.
Step 3. View the SER report with the SER command.
Step 4. Clear the SER report with the SER C command.