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SEL Application Guide 2015-12 Date Code 20150401
In addition, you can use the target command to monitor the status of Relay Word bits such as
87BLKL, 87BLK, and 87LST to troubleshoot issues, like the watchdog error, that inhibit 87L
function in the SEL-411L.
Note: Noticing whether the red and green transmit and receive lights are illuminated on the
back of the SEL-411L is one way to verify that the fiber connections on the channel ports
on the back of the SEL-411L are correct.
87L CHARACTERISTIC TEST METHODS
There are two methods to test the 87L characteristics, depending on the availability of personnel
and equipment and the choice of testing philosophy:
• Single-terminal characteristic testing: Use a single test set to inject current at one
terminal. The channels do not have to be in use, and local and remote currents are
simulated locally by the test set.
• Multiterminal characteristic testing: Use multiple test sets at multiple terminals. Test sets
are satellite-synchronized, channels are in use, and currents can be ramped at all
terminals.
SINGLE-TERMINAL AND MULTITERMINAL CHARACTERISTIC TESTS
In the single-terminal mode, you can apply both local and remote currents to one SEL-411L. This
allows for the simulation of independently adjustable local and remote currents without the need
to apply any current to the remote relay(s). Figure 3 depicts a single-terminal 87L characteristic
test.
Figure 3 Single test set connection to a single relay
Figure 4 shows a multiterminal 87L characteristic test.
87L 87LTest Set
V, I
Test Set
Satellite
Time
V, I
Figure 4 Test set connections to the relays at multiple terminals
The following are examples of entering the test mode for single-terminal and multiterminal tests,
respectively:
=>>TEST 87L
Entering 87L Test Mode
Select Test: Characteristic or Loopback (C,L) ? c
Test Mode: Single, Multi Terminal, or Disabled (S,M,D) ? s
87L Element: (A,B,C,Q,G) ? |
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