ABB RELION 670 Series Installation Manual page 52

Section 6
Connecting
6
7
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 25.
CT 1500/5
Star/Wye
Connected
IEC07000194 V4 EN-US
Figure 25: CT connections for restricted earth fault protection
Pos
1
2
3
4
5
6
46
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.
1
AI01 (I)
2
3
AI02 (I)
4
5
6 AI03 (I)
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
1MRK514024-UEN A
GUID-D68A237F-610C-4AF0-870F-273117F64D92 v10
SMAI2
BLOCK AI3P
^GRP2L1 AI1
^GRP2L2 AI2
^GRP2L3 AI3
^GRP2N AI4
TYPE AIN
1 2 3
5
IEC07000194_4_en.vsd
Installation manual