Galvanic X.21 Line Data Communication (X.21-Ldcm); Introduction; Design - ABB Relion 670 Series Application Manual

Section 5
Communication set-up
Table 23:
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
5.4

Galvanic X.21 line data communication (X.21-LDCM)

5.4.1

Introduction

The galvanic X.21 line data communication module is used for connection to
telecommunication equipment, for example leased telephone lines. The module supports 64
kbit/s data communication between IEDs.
Examples of applications:
• Line differential protection
• Binary signal transfer
5.4.2

Design

The galvanic X.21 line data communication module uses a ABB specific PC*MIP Type II format.
66
Example of calculating the optical budget (maximum distance)
Short range (SR)
Multi-mode fiber
glass 50/125 μm
1MRK0002122-AB
2 km
6 dB
2 dB
0.3 dB
0.1 dB
0.2 dB
8.6 dB
9 dB
0.4 dB
© Copyright 2017 ABB. All rights reserved
Short range (SR) Medium range (MR)
Multi-mode fiber Single-mode fiber
glass 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
0.45 dB 0.64 dB
0.3 dB 0.8 dB
0.3 dB 0.8 dB
12.05 dB 26.04 dB
13 dB 26.8 dB
0.95 dB 0.76 dB
Communication set-up, 670/650 series
1MRK 505 382-UEN E
Long range (LR)
Single-mode fiber
glass 9/125 μm
1MRK002311-BA
120 km
25.2 dB
0.6 dB
0.96 dB
1.2 dB
1.2 dB
28.56 dB
28.7 dB
0.14 dB
GUID-75B89AAC-1A2D-4774-B357-88F7AB7F392A v1
GUID-D02150FC-54F5-4CE4-8D3D-9F8796B6A527 v3
GUID-0570749A-516C-47D6-A818-83416759BA90 v5
Application Guide