14 END-TO-END COMMUNICATION TESTS
If the IED is being used in a scheme with InterMiCOM
64
communications y
ou must perform end-to-end testing of
the protection communications channels.
In this section all loopbacks are removed and satisfactory communications between line ends of the IEDs in the
scheme are confirmed.
Note:
End-to-end communication requires a working telecommunication channel between line ends (which may be a multiplexed
link or may be a direct connection). If the telecommunication channel is not available, it is not possible to establish end-to end
communication. Unless otherwise directed by local operational practise, follow the instructions in this section so the scheme
is ready for full operation when the telecommunications channels become available.
Note:
The trip cir
cuit should remain isolated during these checks to prevent accidental operation of the associated circuit breaker.
14.1 REMOVE LOCAL LOOPBACKS
As well as removing the loopback, this section checks that all wiring and optical fibre are reconnected. If P592 or
P593 inter
face units are installed the application-specific settings are also applied.
1. Check the alarm records to ensure that no communications failure alarms have occurred while the
loopback test was in progress. If it was necessary to ‘fail’ the communications while testing the non-current
differential elements, observe the communications behaviour for a few minutes before removing the
loopbacks.
2. After you are satisfied with the communications behaviour in loopback, set COMMISSION TESTS > Test Mode
and Test Loopback to Disabled.
Note:
Most of the required optical signal power levels have already been measured and recorded. If all signalling uses P59x
interface units, no further measurements are required. If, however, direct fibre or C37.94 communications are used, further
measurements are needed.
14.1.1 RESTORING DIRECT FIBRE CONNECTIONS
When restoring direct fibre connections, check the optical power level received from the remote IED(s).
1. Remove the loopback test fibres and at both ends of each channel used, reconnect the fibre optic cables for
communications between IEDs.
2. For each channel fitted, remove the fibre connecting to the optical receiver (RX).
3. Using an optical power meter measure the strength of the signal received from the remote IED. The
measurements should be within -25.4 dBm and -16.8 dBm for 850 nm fibre connections and between
-37 dBm and -7 dBm for 1300 nm fibre connections
4. Record the received power level(s).
5. Reconnect the fibre(s) to the IED receiver(s).
Warning:
NE
VER look directly into the transmit port or the end of an optical fibre, as this could
severely damage your eyes.
Chapter 20 - Commissioning Instructions P54A/B/C/E
482 P54xMED-TM-EN-1
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