ABB Relion 670 Series Applications Manual page 126

Section 7
Differential protection
7.1.3 Connection examples for high impedance differential protection
7.1.3.1 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 51.
CT 1200/1
Star/Wye
Connected
CT 1200/1
Star/Wye
Connected
ANSI09000169 V4 EN-US
Figure 51:
Pos
1
120
WARNING! USE EXTREME CAUTION! Dangerously high voltages might be present
on this equipment, especially on the plate with resistors. De-energize the primary
object protected with this equipment before connecting or disconnecting wiring or
performing any maintenance. The plate with resistors should be provided with a
protective cover, mounted in a separate box or in a locked cubicle. National law and
standards shall be followed.
L1 L2 L3
(A) (B) (C)
1
Protected Object
L1 L2 L3
(A) (B) (C)
CT connections for high impedance differential protection
Description
Scheme grounding point
It is important to insure that only one grounding point exist in this scheme.
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7
1
AI01
2
(I)
3
AI02
4
(I)
5
AI03
6
(I)
7
AI04
8
(I)
9
AI05
1
(I)
0
1
AI06
1
1
(I)
2
N
L3 (C)
L2 (B)
L1 (A)
N
L3 (C)
L2 (B)
L1 (A)
1
X1 11 12 13 14
2
3
3-Ph Plate with Metrosils and Resistors
1MRK 511 401-UUS F
GUID-8C58A73D-7C2E-4BE5-AB87-B4C93FB7D62B v5
GUID-C12CCAAF-5AE5-4A9C-AC9C-F56A66FD2C14 v8
SMAI2
BLOCK G2AI3P
REVROT G2AI1
^GRP2_A G2AI2
^GRP2_B G2AI3
^GRP2_C G2AI4
^GRP2_N G2N
IED
4
5
2 3 4 5 6 7
X X
6
ANSI09000169-4-en.vsdx
Bay control REC670
Application manual