10-2 L30 Line Current Differential System GE Multilin
10.1 TESTING 10 COMMISSIONING
10
17. Verify and record that Remote Loopback Test fails during communications failures as follows: start test as per Steps 13
to 14 and in 2 to 5 seconds disconnect the fiber Rx cable on the corresponding channel.
Expected result: The "Running Remote Loopback Test" message appears. When the channel is momentarily cut off,
the "Remote Loopback Test FAILED" message is displayed. The status check should read as fol-
lows: ACTUAL VALUES STATUS CHANNEL TESTS CHANNEL 1(2) LOCAL LOOPBACK STATUS: "Fail"
18. Re-connect the fiber Rx cable. Repeat Steps 13 to 14 and verify that Remote Loopback Test performs properly again.
19. Verify and record that Remote Loopback Test fails if communications are not connected properly by disconnecting the
fiber Rx cable and repeating Steps 13 to 14.
Expected result:The ACTUAL VALUES STATUS CHANNEL TESTS CHANNEL 1(2) REMOTE LOOPBACK TEST:
"Fail" message should be constantly on the display.
20. Repeat Steps 13 to 14 and verify that Remote Loopback Test is correct.
21. Make the following setting change in both relays: TESTING TEST MODE: "Disabled"
During channel tests, verify in the
ACTUAL VALUES STATUS CHANNEL TESTS CHANNEL 1(2) LOST PACK-
ETS display that the values are very low – even 0. If values are comparatively high, settings of communica-
tions equipment (if applicable) should be checked.
10.1.2 CLOCK SYNCHRONIZATION TESTS
The 87L clock synchronization is based upon a peer-to-peer architecture in which all relays are Masters. The relays are
synchronized in a distributed fashion. The clocks are phase synchronized to each other and frequency synchronized to the
power system frequency. The performance requirement for the clock synchronization is a maximum error of ±130 μs.
All tests are verified by using PFLL status displays. All PFLL status displays must be either OK or Fail.
1. Ensure that Steps 1 through 7 inclusive of the previous section are completed.
2. Verify and record that both relays have established communications with the following checks after 60 to 120 seconds:
ACTUAL VALUES STATUS CHANNEL TESTS CHANNEL 1(2) STATUS: “OK”
ACTUAL VALUES STATUS CHANNEL TESTS REMOTE LOOPBACK STATUS: “n/a”
ACTUAL VALUES STATUS CHANNEL TESTS PFLL STATUS: “OK”
3. Disconnect the fiber Channel 1(2) Tx cable for less than 66 ms (not possible with direct fiber module).
Expected result:
ACTUAL VALUES STATUS CHANNEL TESTS CHANNEL 1(2) STATUS: “OK”
ACTUAL VALUES STATUS CHANNEL TESTS REMOTE LOOPBACK STATUS: “n/a”
ACTUAL VALUES STATUS CHANNEL TESTS PFLL STATUS: “OK”
If fault conditions are applied to the relay during these tests, it trips with a specified 87L operation time.
4. Disconnect the fiber Channel 1(2) Tx cable for more than 66 ms but less than 5 seconds.
Expected result:
ACTUAL VALUES STATUS CHANNEL TESTS CHANNEL 1(2) STATUS: “OK”
ACTUAL VALUES STATUS CHANNEL TESTS REMOTE LOOPBACK STATUS: “n/a”
ACTUAL VALUES STATUS CHANNEL TESTS PFLL STATUS: “OK”
If fault conditions are applied to the relay (after the channel is brought back) during these tests, it trips with a specified
87L operation time plus 50 to 80 ms required for establishing PFLL after such interruption.
5. Disconnect the fiber Channel 1(2) Tx cable for more than 5 seconds.
Expected result:
ACTUAL VALUES STATUS CHANNEL TESTS CHANNEL 1(2) STATUS: “OK”
ACTUAL VALUES STATUS CHANNEL TESTS REMOTE LOOPBACK STATUS: “n/a”
ACTUAL VALUES STATUS CHANNEL TESTS PFLL STATUS: “Fail”
6. Reconnect the fiber Channel 1(2) Tx cable and in 6 to 8 seconds confirm that the relays have re-established communi-
cations again with the following status checks:
ACTUAL VALUES STATUS CHANNEL TESTS CHANNEL 1(2) STATUS: “OK”
ACTUAL VALUES STATUS CHANNEL TESTS REMOTE LOOPBACK STATUS: “n/a”
ACTUAL VALUES STATUS CHANNEL TESTS PFLL STATUS: “OK”
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