Hitachi 670 Series Installation Manual page 53

1MRK514026-UUS Rev. P
5
6
7
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 25.
CT 1500/5
Star/Wye
Connected
ANSI09000170 V5 EN-US
Figure 25:
Pos
1
2
3
4
5
670 series
Installation manual
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
CT connections for restricted earth fault protection
Description
Scheme grounding point
Ensure that only one grounding point exists in this scheme.
One-phase plate with stabilizing resistor and metrosil. Protective ground 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.
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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
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
5
ANSI09000170-5-en.vsdx
Section 6
Connecting
47