ABB Relion 670 Series Installation Manual page 74

Section 6
Connecting
shield shall be properly connected to the IED chassis with the cable clamp, where the maximum
open conductor length is 40 mm (1.57") between clamp and terminals, see Figure 32. If double
shielded cable is used, the inner cable shielding should be connected at the external equipment
end only. At the IED terminal end, the inner shield should be isolated. The inner and outer
shieldings are connected to the external equipment according to the installation instructions for
the actual equipment. Use insulating tape for the inner shield to prevent contact with the IED
chassis. Make sure that the IEDs are properly grounded with as short connections as possible from
the ground screw, for example to an grounded frame.
The IED and the external equipment should preferably be connected to the same battery.
1 2 3
X1
IED
ANSI07000141 V1 EN-US
Figure 47: Communication cable installation, 2-wire
Where:
1
2
3
4
Cc
68
Cc
4 5 6
PG
The inner shields shall be connected together (with an isolated terminal block) and only have one
connection point in the whole system, preferably at the external equipment (PC).
The outer shield shall be connected to the IED chassis in every cable end. Use the shield connection clamp
at all IEDs. The first IED will have only one cable end but all others require two.
Connect according to installation instructions for the actual equipment, observe the 120 ohms
termination.
Connect the screens according to the installation instructions for the actual equipment.
Shield connection clamp, see Figure 32.
Communication cable
Cc
1)
1 2 3 4 5 6
X1
IED
PG PG
1MRK 514 026-UUS F
2)
External
Equipment (PC)
PG 1) 3)
en07000141_ansi.vsd
Installation manual
670 series