Connection Examples For High Impedance Differential Protection; Connections For Three-Phase High Impedance Differential Protection - ABB Relion REC670 Applications Manual

Section 6
Differential protection
6.1.3 Connection examples for high impedance differential
protection
6.1.3.1

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 34.
CT 1200/1
Star/Wye
Connected
CT 1200/1
Star/Wye
Connected
IEC07000193 V4 EN-US
Figure 34: CT connections for high impedance differential protection
Pos
1
2
3
4
92
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)
Description
Scheme earthing point
It is important to insure that only one earthing point exist in this scheme.
Three-phase plate with setting resistors and metrosils. Protective earth is a separate 4 mm screw
terminal on the plate.
Necessary connection for three-phase metrosil set.
Position of optional test switch for secondary injection into the high impedance differential IED.
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)
11 12 13 14
X1
2
3
3-Ph Plate with Metrosils and Resistors
1MRK 511 358-UEN A
GUID-8C58A73D-7C2E-4BE5-AB87-B4C93FB7D62B v5
GUID-C12CCAAF-5AE5-4A9C-AC9C-F56A66FD2C14 v8
SMAI2
BLOCK AI3P
^GRP2L1 AI1
^GRP2L2 AI2
^GRP2L3 AI3
^GRP2N AI4
TYPE AIN
IED
4
5
1 2 3 4 5 6 7
X X
6
IEC07000193_4_en.vsd
Application manual