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.
6.3 Fibre optic loop
M11905-3 v6
The SP
A 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 12: Max distances between IEDs/nodes
glass < 1000 m according to optical budget
plastic < 25 m (inside cubicle) according to optical budget
6.4 Optical budget calculation for serial communication
with SPA/IEC
M11736-4 v2
Table 13: Example
Distance 1 km
Glass
Distance 25 m
Plastic
Maximum attenuation - 11 dB - 7 dB
4 dB/km multi mode: 820 nm - 62.5/125 um 4 dB -
0.16 dB/m plastic: 620 nm - 1mm - 4 dB
Margins for installation, aging, and so on 5 dB 1 dB
Losses in connection box, two contacts (0.5 dB/contact) 1 dB -
Losses in connection box, two contacts (1 dB/contact) - 2 dB
Margin for 2 repair splices (0.5 dB/splice) 1 dB -
Maximum total attenuation 11 dB 7 dB
1MRK 505 378-UEN A Section 6
Establishing connection and verifying the SPA/IEC communication
Line differential protection RED670 2.2 IEC 65
Commissioning manual
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