Fibre Optic Loop; Optical Budget Calculation For Serial Communication With Spa/Iec - ABB rec670 Commissioning Manual

1MRK 511 360-UEN A
Establishing connection and verifying the SPA/IEC communication
6.3
6.4
Bay control REC670 2.1 IEC
Commissioning manual
1. Check that the master system time-out for response from the IED, for example
after a setting change, is > 40 seconds.
2. Use a protocol analyzer and record the communication between the IED and the
IEC master. Check in the protocol analyzer's log that the IED answers the master
messages.
3. Generate one binary event by activating a function that is configured to an event
block where the used input is set to generate events on IEC. The configuration
must be made with the PCM600 software. Verify that the event is presented in
the IEC master system.
During the following tests of the different functions in the IED, verify that the events
and indications in the IEC master system are as expected.

Fibre optic loop

The SPA communication is mainly used for SMS. It can include different numerical
IEDs with remote communication possibilities. The fibre optic loop can contain <
20-30 IEDs depending on requirements on response time. Connection to a personal
computer (PC) can be made directly (if the PC is located in the substation) or by
telephone modem through a telephone network with ITU (CCITT) characteristics.
Table 9: Max distances between IEDs/nodes
glass < 1000 m according to optical budget
plastic < 25 m (inside cubicle) according to optical budget
Optical budget calculation for serial communication
with SPA/IEC
Table 10: Example
Maximum attenuation
4 dB/km multi mode: 820 nm - 62.5/125 um
0.16 dB/m plastic: 620 nm - 1mm
Margins for installation, aging, and so on
Losses in connection box, two contacts (0.5 dB/contact)
Losses in connection box, two contacts (1 dB/contact)
Margin for 2 repair splices (0.5 dB/splice)
Maximum total attenuation
Section 6
Distance 1 km Distance 25 m
Glass Plastic
- 11 dB - 7 dB
4 dB -
- 4 dB
5 dB 1 dB
1 dB -
- 2 dB
1 dB -
11 dB 7 dB
59