Connection Examples For High Impedance Differential Protection - ABB RET670 Applications Manual

1MRK504116-UUS C
3.5.3.3
Application manual

Connection examples for high impedance differential protection

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 38.
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)
ANSI09000169 V1 EN
Figure 38: CT connections for high impedance differential protection
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 3
IED application
8
SMAI2
AI01
BLOCK AI3P
(I)
^GRP2_A
^GRP2_B
AI02
^GRP2_C
(I)
^GRP2_N
AI03
TYPE
(I)
9
AI04
(I)
AI05
(I)
AI06
(I)
IED
4
1 2 3 4 5 6
14
3
X X
ANSI09000169_1_en.vsd
AI1
AI2
AI3
AI4
AIN
10
5
7
6
141