ABB ZX2 - Page 57

3. INSTALLATION OF THE SWITCHGEAR AT SITE 57
Grounding of open delta windings
If the open delta windings of the voltage trans-
formers are damped with a resistor, the windings
connected in an open delta are to be grounded at
one point. The circuit can be grounded
• in the low voltage compartment
(fig. 3.3.7.6.3) or
• on the terminal block of a voltage transformer
(fig. 3.3.7.6.4).
Perform measurements to ascertain which
grounding method applies to your system.
—
Fig.3.3.7.6.3:
Grounding of the
circuit in the low
voltage compartment
—
Fig.3.3.7.6.4:
Grounding the circuit
on the terminal board
of a transformer
-F

dn
da
-T15L3
dn
da
-T15L2
dn
da
-T15L1
-F

dn
da
-T15L3
dn
da
-T15L2
dn
da
-T15L1
Hazard warning
Do not ground here!
Without grounding
screw on terminal "dn"
Hazard warning
Do not ground here!
Without grounding
screw on terminal "dn"
Hazard warning
Ground here!
With grounding screw on
terminal "dn"
Grounding in the low voltage compartment
—
Fig. 3.3.7.9.3
—
Fig. 3.3.7.9.4