Connection Examples - ABB RET670 Installation And Commissioning Manual

1MRK 504 088-UEN C
5.4.1.4
Installation and commissioning manual

Connection examples

WARNING! USE EXTREME CAUTION! Dangerously high
voltages might be present on this equipment, especially on the plate
with resistors. Do any maintenance ONLY if the primary object
protected with this equipment is de-energized. If required by
national law or standard, enclose the plate with resistors with a
protective cover or in a separate box.
Connections for three-phase high impedance differential protection
Generator, reactor or busbar differential protection is a typical application for three-
phase high impedance differential protection. Typical CT connections for three-
phase high impedance differential protection scheme are shown in figure 28.
L1 L2 L3
(A) (B) (C)
CT 1200/1
Star/Wye
Connected
Protected Object
CT 1200/1
Star/Wye
Connected
L1 L2 L3
(A) (B) (C)
IEC07000193 V2 EN
Figure 28: CT connections for high impedance differential protection
Pos Description
1 Scheme earthing point
Note that it is of outmost importance to insure that only one earthing point
exist in such scheme.
2 Three-phase plate with setting resistors and metrosils.
7
1
2
3
4
5
6
7
8
9
1
0
1
1
1
1
2
N
L3 (C)
L2 (B)
L1 (A)
N
L3 (C)
L2 (B)
L1 (A)
X1 11 12 13
2
3-Ph Plate with Metrosils and Resistors
Section 5
Installing the IED
8
SMAI2
AI01
BLOCK
(I)
^GRP2L1
^GRP2L2
AI02
^GRP2L3
(I)
^GRP2N
AI03
TYPE
(I)
9
AI04
(I)
AI05
(I)
AI06
(I)
IED
4
1 2 3 4 5 6
14
3
X X
AI3P
AI1
AI2
AI3
AI4
AIN
10
5
7
6
IEC07000193_2_en.vsd
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