Checking The V.t. Connections; Checking The Auxiliary Supply Connections - ABB REG316 4 Series Operating Instructions Manual

ABB Switzerland Ltd
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.
T
a) normal load condition
Fig. 7.5
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.
7-10
R
U
R
U
T
S
Voltages in an ungrounded three-phase power system
REG 316*4 1MRB520049-Uen / Rev. C
R
U
R
T
b) E/F on T phase
U
0
S
HEST 945 002 C