ABB Relion 670 Series Applications Manual page 126

Section 7
Differential protection
6
7
7.1.3.2 Connections for 1Ph High impedance differential protection HZPDIF
Restricted earth fault protection is a typical application for 1Ph High impedance differential
protection HZPDIF. Typical CT connections for the high impedance based protection scheme
are shown in figure 52.
CT 1500/5
Star/Wye
Connected
IEC07000194 V5 EN-US
Figure 52: CT connections for restricted earth fault protection
Pos
1
2
3
4
5
6
120
Factory-made star point on a three-phase setting resistor set.
The star point connector must be removed for installations with 670 series IEDs.
This star point is required for RADHA schemes only.
Connections of three individual phase currents for high impedance scheme to three CT inputs in the
IED.
L1 L2 L3
(A) (B) (C)
Protected Object
L1 L2 L3
(A) (B) (C)
1
Description
Scheme earthing point
Ensure that only one earthing point exists in this scheme.
One-phase plate with stabilizing resistor and metrosil. Protective earth is a separate 4 mm screw
terminal on the plate.
Necessary connection for the metrosil.
Position of optional test switch for secondary injection into the high impedance differential IED.
Necessary connection for stabilizing resistor.
How to connect the high impedance restricted earth fault protection scheme to one CT input in IED.
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1
AI01 (I)
2
3
AI02 (I)
4
5
AI03 (I)
6
6
7
AI04 (I)
8
9
AI05 (I)
10
11
AI06 (I)
12
N
4
N
4 5
X1
2
3
1-Ph Plate with Metrosil and Resistor
1MRK 511 401-UEN Rev. K
GUID-D68A237F-610C-4AF0-870F-273117F64D92 v10
SMAI2
BLOCK G2AI3P
REVROT G2AI1
^GRP2L1 G2AI2
^GRP2L2 G2AI3
^GRP2L3 G2AI4
^GRP2N G2N
IED
1 2 3
5
=IEC07000194=5=en=Original.vsdx
Bay control REC670
Application manual