ABB PrimeGear ZX0 Product Manual page 43

I N S T A L L A T I O N O F T H E S W I T C H G E A R A T S I T E
—
2.3.5.1 Wiring of the voltage transformers
Fig. 2.3.5.1.1 Possible
The voltage transformers are fitted with terminal
terminal board
configurations
boards. The possible configurations of terminal
—
boards can be found in Fig.2.3.5.1.1 and table
Fig. 2.3.5.1.2 Earthing
of terminals using
2.3.5.1.1.
earthing Wire
Notes：All N and n terminals should be earthed by
wiring to the panel frame!
—
Table 2.3.5.1.1: Possible terminal board configurations
Y connected winding
1
2
1
2
N The terminal must be earthed via the earthing screw!
n Earthing of the terminal in accordance with the circuit diagram!
Earthing screw fitted in accordance with the circuit diagram and
dn
Fig.2.3.5.1.3 or 2.3.5.1.4!
In a voltage transformer version with 2 windings
plus tap or 2 windings plus open delta winding, "N"
is implemented at the base plate of the voltage
transformer.
Earthing of terminals on the voltage transformer
terminal board using earthing wire
Connections to earth potential can be established
by means of earthing wire on the terminals of the
terminal board. Fig.2.3.5.1.2 illustrates this using
the example of a voltage transformer with one
secondary winding.
Wiring the voltage transformers
The cable harnesses for wiring of the transformers
are prepared at the works and wired to the low
voltage compartment. Wire the transformers as
follows.
—
Fig. 2.3.5.1.2
VT secondary windings number
Open delta winding
1
1
1
—
Fig. 2.3.5.1.1
N 1a 1n
√ √ √
√ √ √
√
√ √ √
√ √ √
When 2 windings plus a tap or 2 windings plus open delta winding, are
used, "N" is implemented by the works at the base plate of the voltage
transformer.
Wire the secondary terminals and the
earthing of the voltage transformers in
accordance with the circuit diagrams.
Check that all terminal screws including
the earthing screws are tightly fastened.
Releasing the earthing screw on the 'N'
terminal leads to potentially lethal
high-voltage at the terminal when the
voltage transformer is in operation!
Releasing the earthing screw on the 'N'
terminal is only permissible for test
purposes on voltage transformers with
de-energized primary!
Always use the original earthing screws!
A N PE
(Behind metal plate
as Fig. 2.3.5.1.2)
a n
Terminal
2a 2n da
√ √
√
√
√ √ √
Connection to earth potential by
means of earthing wire
43
dn
√
√
√