11-2 Testing and Troubleshooting Date Code 20010731
SEL-352-1, -2 Instruction Manual
displayed, if the fault level overcurrent element (50FT) asserts, the far right LED illuminates.
See Appendix F: Relay Word for a list of all Relay Word elements.
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> button or by
issuing the TAR R command from the serial port.
Output Contact Assertion
To test using this method, set one programmable output contact to assert when the element under
test picks up. With the SET n command, enter the Relay Word bit name of the element under
test.
For an “a” contact, when the condition asserts, the output contact closes. When the condition
deasserts, the output contact opens.
For a “b” 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” contacts with a solder jumper. Refer to
Section 2: Installation for jumper locations. Using contact operation as an indicator, you can
measure element operating characteristics, stop timers, etc.
Tests in this section assume an “a” output contact.
Sequential Events Recorder (SER)
To test using this method, set the SER to trigger for the element under test. Using 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. View the SER report with
the SER command. Clear the SER report with the SER C command.
Low-Level Test Interface
The SEL-352 Relay has a low-level test interface between the calibrated input module and the
separately calibrated processing module. You may test the relay in either of two ways:
conventionally, by applying ac current signals to the relay inputs; or by applying low magnitude
ac voltage signals to the low-level test interface. Access the test interface by removing the relay
front panel.
Figure 11.1 shows the low-level interface connections. This drawing also appears on the inside
of the relay front panel. Remove the ribbon cable between the two modules to access the outputs
of the input module and the inputs to the processing module (relay main board).
You can test the relay processing module using signals from the SEL-RTS Low-Level Relay
Test System. Never apply voltage signals greater than 9 V peak-to-peak to the low-level test
interface. Figure 11.1 shows the signal scaling factors.
To Next Page
