During the following tests of the different functions in the IED, verify that theevents and indications in the IEC master system are as expected.6.3 Fibre optic loop M11905-3 v6The SPA communication is mainly used for SMS. It can include differentnumerical IEDs with remote communication possibilities. The fibre optic loop cancontain < 20-30 IEDs depending on requirements on response time. Connection toa personal computer (PC) can be made directly (if the PC is located in the station)or by telephone modem through a telephone network with ITU (CCITT)characteristics.Table 7:Max distances between IEDs/nodesglass < 1000 m according to optical budgetplastic < 25 m (inside cubicle) according to optical budget6.4 Optical budget calculation for serial communicationwith SPA/IEC M11736-4 v2Table 8:ExampleDistance 1 kmGlassDistance 25 mPlasticMaximum attenuation - 11 dB - 7 dB4 dB/km multi mode: 820 nm - 62.5/125 um 4 dB -0.16 dB/m plastic: 620 nm - 1mm - 4 dBMargins for installation, aging, and so on 5 dB 1 dBLosses in connection box, two contacts (0.5 dB/contact) 1 dB -Losses in connection box, two contacts (1 dB/contact) - 2 dBMargin for 2 repair splices (0.5 dB/splice) 1 dB -Maximum total attenuation 11 dB 7 dB1MRK 506 383-UEN A Section 6Establishing connection and verifying the SPA/IEC communicationLine distance protection REL650 2.2 IEC 51Commissioning manual
