57
Fibre optic loop Chapter 8
Establishing connection and
verifying the
SPA/IEC-communication
3 Fibre optic loop
The SPA communication is mainly used for SMS. It can include different numerical relays/ter-
minals with remote communication possibilities. The fibre optic loop can contain < 20-30 ter-
minals 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 7: Max distances between terminals/nodes
Figure 23: Example of SPA communication structure for a station monitoring system
glass < 1000 m according to optical budget
plastic < 25 m (inside cubicle) according to optical budget
Where:
1 A separate minute pulse synchronization from station clock to obtain ± 1 ms accuracy for
time tagging within the substation might be required.
Local monitoring
system with
PCM600
IED670 IED670IED670
Optical to electrical
converter, e.g. SPA-ZC 22
or Fiberdata modem
Teleph
one
modem
Teleph
one
modem
Remote monitoring
system with
PCM600
en05000672.vsd
To Next Page
Loading...
