ABB Relion 670 Series Applications Manual page 127

1MRK 511 401-UUS F
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7.1.3.2 Connections for 1Ph High impedance differential protection HZPDIF (87)
Restricted earth fault protection is a typical application for 1Ph High impedance differential
protection HZPDIF (87). Typical CT connections for the high impedance based protection scheme
are shown in figure 52.
CT 1500/5
Star/Wye
Connected
ANSI09000170 V5 EN-US
Figure 52: CT connections for restricted earth fault protection
Bay control REC670
Application manual
Three-phase plate with setting resistors and metrosils. Protective ground 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.
Necessary connection for setting resistors.
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
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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 1
X1
2
3
1-Ph Plate with Metrosil and Resistor
Differential protection
GUID-D68A237F-610C-4AF0-870F-273117F64D92 v10
SMAI2
BLOCK G2AI3P
REVROT G2AI1
^GRP2_A G2AI2
^GRP2_B G2AI3
^GRP2_C G2AI4
^GRP2_N G2N
IED
2 3
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ANSI09000170-5-en.vsdx
Section 7
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