ABB Relion 670 Series Applications Manual page 463

1MRK 505 370-UUS Rev. K
Table 63:
Type of LDCM
Type of fibre
Modem type
Maximum distance
Attenuation in fibre-
optic cables
2 contacts
Factory splice
attenuation
Repair splices
Fiber margin for aging
Total attenuation
Optical link budget
Link margin
1) Applicable for revision r11 and later.
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
TransmCurr is used to select among the following:
Busbar protection REB670
Application manual
Example of calculating the optical budget (maximum distance)
Short range (SR)
Multi-mode fiber glass
50/125 μm
1MRK0002122-AB
2 km
6 dB
3
dB
0.5 dB
0.25 dB
0.2 dB
9.95 dB
11.8 dB
1.85 dB
© 2017 - 2021 Hitachi Power Grids. All rights reserved
Short range (SR) Medium range (MR)
Multi-mode fiber glass Single-mode fiber
62.5/125 μm glass 9/125 μm
1MRK0002122-AB 1MRK002311-AA
3 km 80 km
9 dB 25.6 dB
3 dB 0.6 dB
0.5 dB 0.64 dB
0.25 dB 0.4 dB
0.3 dB 0.8 dB
13.05 dB 28.04 dB
18.8 dB 28.8 dB
30.8 dB
5.75 dB 0.76 dB
2.76 dB
Remote communication
Long range (LR)
Single-mode fiber
glass 9/125 μm
1MRK002311-BA
120 km
25.2 dB
0.6 dB
0.96 dB
0.6 dB
1.2 dB
28.56 dB
28.7 dB
1)
0.14 dB
1)
Section 18
457