Grounding Resistor R E; Contactor; Residual Current C.t - ABB REG316 4 Series Operating Instructions Manual

ABB Switzerland Ltd
only a limited damping capacity. The output power of the v.t. in
the example varies at a continuous current of 2 A between 577
and 831 VA.
When the main priority is to prevent mal-operation, the resistor
Rp is chosen according to the maximum continuous rating of the
v.t's which is usually in the range of 5 to 10 % of the permissible
10 s current. Where the v.t's are also used for metering, it should
be noted that the voltage and phase errors increase at the
maximum continuous current.
4.2.5.6. Grounding resistor R
The grounding resistor must be rated for 10 s. A voltage drop of
20 % is allowed if a v.t. is used as grounding transformer. For a
ground fault current of 20 A and a rated voltage of UN = 10.5 kV,
the recommended value of the resistor is:
U
N
[V]
10,500
4.2.5.7.

Contactor

The contactor switches both ends of the grounding resistor R
4.2.5.8.

Residual current c.t.

Alternative I:
1 core-balance c.t. 100/1 A, rated burden 2.5 W .
Alternative II:
3 bushing c.t's, .../5 A - 33/1 A, rated burden 1.5 W .
The above burdens apply for c.t. leads of 2 x 100 m with a gauge
of 4 mm
4-34
e
U
broken
D
[V] [ W ]
500 250
2 .
REG 316*4 1MRB520049-Uen / Rev. B
R R
p e
[A] v.t.
1.7 W
2
I
2
[A] 10 s
240
.
e