Sel 411L - Table 11.4 Test Mode Output Supervision under Default Settings; Test Mode

P.11.4
SEL-411L Relay Protection Manual Date Code 20151029
Testing and Troubleshooting
Test Mode
relay trips will be flagged as an error (see 87L Watchdog Monitor on
page P.3.97 for details).
It is possible to test the differential element on an in-service line solely from
one terminal using the TEST 87L command and selecting a characteristic
test. A signal is sent to all remote relays to inhibit operation of the differential
at the remote terminals. Be sure to restore line currents to the relay prior to
terminating the TEST 87L command. Note that it is necessary to restore the
line currents and terminate the TEST 87L command when switching between
characteristic tests of the various elements (A, B, C, Q, and G).
When the relay is tested using the TEST MODE feature, the supervising logic
is suppressed. It is recommended to use TEST MODE in order to prevent 87L
watchdog operations. It is possible to test the relay without using TEST
MODE. However, the tester must simulate a fault at each relay
simultaneously.
Test Mode
The objective of the Test Mode is to allow all the protection functions to be
thoroughly tested, but to avoid the output contacts to close. To this end, the
relay supervises the output contacts used for breaker tripping and closing and
for pilot scheme keying. Table 11.4 shows the default Output settings. Notice
the inclusion of Latch PLT04.This latch is programmed in an AND
combination with Output Contacts OUT201, OUT202 OUT203 and OUT207.
To enter the Test Mode, press the front-panel pushbutton labeled RELAY TEST
MODE. Pressing the pushbutton sets protection Latch PLT04 and illuminates
the pushbutton LED to indicate that the Test Mode is active. When PLT04
asserts, Output Contacts OUT201, OUT202 OUT203 and OUT207 are
blocked. Note that if you intend to use the Test Mode as described here, then
the supervising settings (PLT04) in the Output settings category must not be
changed. If you remove PLT04 from the Output settings, the relay may issue a
trip to a breaker during testing. If Test Mode is not used, then external test
switches must be used to isolate the relay outputs from control circuits during
testing.
Table 11.4 Test Mode Output Supervision Under Default Settings
OUT201 (3PT OR TPA1) AND NOT PLT04 #THREE POLE TRIP
OUT202 (3PT OR TPA1) AND NOT PLT04 #THREE POLE TRIP
OUT203 BK1CL AND NOT PLT04 #BREAKER CLOSE COMMAND
OUT204 KEY AND PLT02 AND NOT PLT04#KEY TX
OUT205 NA
OUT206 87TOUT
OUT207 PLT04 #RELAY TEST MODE
OUT208 NOT (SALARM OR HALARM)