ABB Relion 670 series - Troubleshooting Central Account Management

Table 13: Example of calculating the optical budget (maximum distance)
Type of LDCM Short range (SR) Short range (SR) Medium range
(MR)
Long range (LR)
Type of fibre Multi-mode fiber
glass 50/125 μm
Multi-mode fiber
glass 62.5/125
μm
Single-mode fiber
glass 9/125 μm
Single-mode fiber
glass 9/125 μm
Modem type 1MRK0002122-
AB
1MRK0002122-
AB
1MRK002311-AA 1MRK002311-BA
Maximum
distance
2 km 3 km 80 km 120 km
Attenuation in
fibre-optic cables
6 dB 9 dB 25.6 dB 25.2 dB
2 contacts 2 dB 3 dB 0.6 dB 0.6 dB
Factory splice
attenuation
0.3 dB 0.45 dB 0.64 dB 0.96 dB
Repair splices 0.1 dB 0.3 dB 0.8 dB 1.2 dB
Fiber margin for
aging
0.2 dB 0.3 dB 0.8 dB 1.2 dB
Total attenuation 8.6 dB 12.05 dB 26.04 dB 28.56 dB
Optical link
budget
9 dB 13 dB 26.8 dB 28.7 dB
Link margin 0.4 dB 0.95 dB 0.76 dB 0.14 dB
ComAlarmDel defines the time delay for communication failure alarm. In
communication systems, route switching can sometimes cause interruptions with a
duration of up to 50 ms. Too short a time delay can thus cause nuisance alarms.
ComAlrmResDel defines the time delay for communication failure alarm reset.
RedChSwTime defines the time delay before switching over to a redundant channel
in case of primary channel failure.
RedChRturnTime defines the time delay before switching back to the primary
channel after channel failure.
AsymDelay denotes asymmetry which is defined as transmission delay minus
receive delay. If fixed asymmetry is known, Echo synchronization method can be
used, provided that AsymDelay is properly set. From the definition follows that
asymmetry is always positive at one end and negative at the other end.
MaxTransmDelay indicates maximum transmission delay. Data for maximum 40
ms transmission delay can be buffered up. Delay times in the range of some ms are
common. If data arrive in wrong order, the oldest data is disregarded.
MaxtDiffLevel indicates the maximum time difference allowed between internal
clocks in respective line ends.
64 kbit mode specific settings
Section 4 1MRK 505 382-UEN B
Analog and binary signal transfer for line differential protection
66 Communication set-up 670/650 series 2.2
Application Guide