Hitachi 670 Series Installation Manual page 66

Section 6
Connecting
The shunt resistor unit REX062, should be installed in the same cubicle where REX060 is installed. The
wiring of REX062 should be carried out according to the guidelines in the
Table 13:
Location
Between REX060 and REX062.
Wiring inside the protection cubicle.
Between REX062 and SIT (Current
Injection)
Between REX060 and SIT (Voltage
measurement)
The Signal Injection Transformer (SIT) should be installed in the generator neutral compartment (for IEC
and ANSI grounding) and the connection should be carried out according to the guidelines in the
14.
Table 14:
Location
Generator neutral compartment
Connecting to protective ground
Connect the protective grounding screw on the rear of each unit to the closest possible grounding point in
the cubicle. Electrical codes and standards require that protective ground cables are green/yellow
conductors with a cross section area of at least 2.5 mm
The cubicle must be properly connected to the station grounding system. Use a conductor with a core
cross section area of at least 4 mm
The protective grounding point for the case of REX061 shall be connected to the same grounding grid of
the generator. REX061 shall be installed in a panel (or cubicle) that is close to the generator to fulfill this
requirement.
60
Guidelines for connection cables for REX062
Guidelines for connection cables between SIT and Generator neutral point
2
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Guideline
Dedicated two-core cable with cross section at least 1.5 mm
terminals X61:14-15 and REX062 terminals X1:6-8, used for measurement of
current sense (voltage signal).
Dedicated two-core cable with cross section at least 2.5 mm
terminals X62:1-2 and REX062 terminals X1:9-10, used for current injection.
Shielded two-core cable with rated voltage at least 600 V AC and cross section
according to the following table.
2
Cable Cross Section (mm )
2.5
4
6
10
16
The cable between the terminals X61:12-13 of REX060 and the low voltage
terminals of SIT shall be a shielded twisted pair cable; this cable is used for the
measurement of the voltage signal.
The shielded twisted pair cable should have cross section 1.5 mm
AWG), lay length not longer than 71 mm, coverage of the shield at least 85%,
rated voltage at least 600 V AC and voltage test at least 2 kV AC for 5 minutes.
The cable UL2586-SB TEW 2X14AWG(41/0.26)LF by Hitachi or an equivalent
cable shall be used. The installation of this cable shall be according to a proper
EMC design, considering that it is a measurement cable with low current and
low voltage signals.
Guideline
High voltage cable with rated voltage appropriated for the
rated voltage of the generator.
2
(AWG 14).
(AWG 12).
1MRK514026-UUS Rev. P
Table 13.
2
between REX060
2
between REX060
Maximum Length of the cable (m)
60
100
150
250
480
2
(or 14
Table
670 series
Installation manual