The various protection, control and annunciator units of the SPACOM and REF, REM, REC and REX products are linked together via the SPA bus, which physically is composed of fiber-optic cables. Two types of fiber-optic cables are used, i.e. plastic core cables and glass-fiber core cables.
The plastic core and glass fiber cables have different optic specifications. Plastic-core cables are used for shorter distances, i.e. under 30 m, whereas glass-fiber cables can be used for distances up to 1000 m.
- Fiber-optic cables delivered with premounted opto-connectors
- Simple mounting, no special tools needed
- Immunity to electrical and electromagnetic interference
- Economical bus solution in comparison with electrical bus
- Standard lengths of cables with premounted opto-connectors
- Being isolators the fibre-optic cables prevent current from flowing between the SPACOM and REF, REM, REC and REX products of a system because the different devices may be on different potential levels.
- Conventional electrical pilot wires of a substation switchgear installation, to a great extent, are replaced with fiber-optic cables which transfers measured values, control commands, status and event data, etc.