Intermicom 64 Communication; Checking The Interface; Setting Up The Loopback - GE P4A Technical Manual

Chapter 20 - Commissioning Instructions
7

INTERMICOM 64 COMMUNICATION

If the IED is used in a scheme with InterMiCOM
purposes.
IM64 is fibre-based. Several different fibre-optic interfaces are available. In general, 1550 nm single-mode fibres, or
1300 nm single-mode or multimode fibres are used for direct connection. 850 nm multimode fibres are generally
used with multiplexing telecommunications equipment.
Note:
It is important that fibres used for testing are correct for the specified interface(s).
Optical fibres should be terminated with BFOC2.5 (ST2.5) connectors. For multimode applications use 50/125 µm
core fibre. Make sure fibre test leads used for measurements are long enough for mode stripping (a method of
reducing loss within the core). We recommend a minimum length of 10 m (30ft) for this.
If Current Differential protection is used, set CONFIGURATION > Current Diff to Enable.
If Current Differential protection is not used, set CONFIGURATION > InterMiCOM64 to Enable.
Warning:
NEVER look directly into the transmit port or the end of an optical fibre, as this could
severely damage your eyes.
7.1

CHECKING THE INTERFACE

Before carrying out the loopback test, you need to check that the interface is transmitting a suitable signal. To
check this ...
1. Set COMMISSIONING TEST > Loopback Mode to External.
2. Using an appropriate fibre-optic cable, connect the Channel 1 transmitter (TX1) to an optical power meter.
Check that the average power transmitted is within the range given in the following table.
3. Record the transmit power level.
4. Repeat for Channel 2 if applicable.
Power
Maximum transmitter power (average value)
Minimum transmitter power (average value)
Note:
If CONFIGURATION > InterMiCOM64 is set to Enable, the signals normally sent and received by and from the
communications interface are routed to and from the signals defined in the Programmable Scheme Logic. If, however,
COMMISSION TESTS > IM64 Test Mode is set to Enabled, an IM64 test pattern is transmitted instead.
7.2

SETTING UP THE LOOPBACK

Set up a communications loopback for each of the two channels.
466
64
communication, you need to configure a loopback for testing
850 nm
multi-mode
-19.8 dBm
-22.8 dBm
1300 nm
multi-mode
-3 dBm
-9 dBm
P54A/B/C/E
1300/1550 nm
single-mode
-3 dBm
-9 dBm
P54xMED-TM-EN-1