ABB REG316 4 Series - Checking the Auxiliary Supply Connections; Checking the V.t. Connections

ABB Switzerland Ltd REG 316*4 1MRB520049-Uen / Rev. C
7-10
7.2.4. Checking the v.t. connections
The v.t’s must be connected in strict accordance with diagram
supplied with the equipment.
The following checks must be carried out to check the v.t. cir-
cuits:
· polarity check
· wiring check
· v.t. circuit grounding.
The rated voltage of an E/F protection scheme is defined as the
voltage which occurs between the terminals “e” and “n” for a
solid phase-to-ground fault. An E/F of this kind, e.g. on T phase
(see Fig. 7.5), causes the voltages of R and S phases to in-
crease from phase-to-neutral to phase-to-phase potential and
these add vectorially to produce a voltage between terminals “e”
and “n", which is three times the phase-to-neutral voltage.
HEST 945 002 C
R
ST
U
T
U
R
R
ST
U
S
U
R
U
0
U
S
u
3
u
·
a) normal load condition b) E/F on T phase
Fig. 7.5 Voltages in an ungrounded three-phase power system
7.2.5. Checking the auxiliary supply connections
Check that the supply is connected with the correct polarity. The
d.c. supply voltage must lie within the permissible operating
range of the power supply unit installed under all operating con-
ditions (see Technical Data for the respective power supply unit).
The power supply unit, type 316NG65 is protected by a fuse,
type T 3.15 A.