9-2 L30 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUALTESTING CHAPTER 9: COMMISSIONING9Expected result — In a few seconds “Yes” changes to “Local Loopback Test PASSED” and then to “No”, signifying thetest was successfully completed and the communication modules operated properly.11. If Channel 2 is used, make the following setting change and repeat Step 10 for Channel 2 as performed for channel 1:TESTING CHANNEL TESTS LOCAL LOOPBACK TEST LOCAL LOOPBACK CHANNEL NUMBER: "2"12. Verify and record that the Local Loopback Test was performed properly with the following status check:ACTUAL VALUES STATUS CHANNEL TESTS CHANNEL 1(2) LOCAL LOOPBACK STATUS: "OK"13. Make the following setting change in one of the relays:TESTING CHANNEL TESTS REMOTE LOOPBACK TEST REMOTE LOOPBACK CHANNEL NUMBER: "1"14. Initiate the Remote Loopback Channel Tests by making the following setting change:TESTING CHANNEL TESTS REMOTE LOOPBACK REMOTE LOOPBACK FUNCTION: "Yes"Expected result — The “Running Remote Loopback Test” message appears; within 60 to 100 seconds, the “RemoteLoopback Test PASSED” message appears for a few seconds and then changes to “No”, signifying that the testsuccessfully completed and communications with the relay were successfully established. The “Remote LoopbackTest FAILED” message indicates that either the communication link quality does not meet requirements (BER less than10–4) or the channel is not established – check the communications link connections.15. If Channel 2 is used, make the following setting change and repeat Step 14 for Channel 2 as performed for Channel 1:TESTING CHANNEL TESTS REMOTE LOOPBACK TEST REMOTE LOOPBACK CHANNEL NUMBER: "2"16. Verify and record the Remote Loopback Test was performed properly with the following status check:ACTUAL VALUES STATUS CHANNEL TESTS CHANNEL 1(2) REMOTE LOOPBACK STATUS: "OK"17. Verify and record that Remote Loopback Test fails during communications failures as follows: start test as per Steps13 to 14 and in two to five 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 displays. The status check reads as follows: 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 thefiber Rx cable and repeating Steps 13 to 14.Expected result — The ACTUAL VALUES STATUS CHANNEL TESTS CHANNEL 1(2) REMOTE LOOPBACK TEST: "Fail"message is 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"9.1.2 Clock synchronization testsThe 87L clock synchronization is based upon a peer-to-peer architecture in which all relays are Masters. The relays aresynchronized in a distributed fashion. The clocks are phase-synchronized to each other and frequency-synchronized to thepower-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 120seconds: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”During channel tests, verify in the ACTUAL VALUES STATUS CHANNEL TESTS CHANNEL 1(2) LOST PACKETSdisplay that the values are very low or even 0. If values are comparatively high, check the settings ofcommunications equipment (if applicable).