ABB REG316 4 Series Operating Instructions Manual page 405

REG 316*4 1MRB520049-Uen / Rev. B
Equations:
DU
= (R
a
³ 2 DU
U
k
I = 0.25 I
I = 0.10 I
³
R
S
DU
= R
i
U
max
4.2.1.2.4. Example
Determination of the stabilising resistor:
C.t's
= 5 W
R
2
=
R
L
50 4
(c.t. lead gauge 4 mm
Maximum earth fault through current:
I = 10,000 A
E
This would be the current for an E/F on an HV system with the
following data:
x " = x
d
=
I 10 000
2
D U
= (5 + 2 x 0.5) x 10 = 60 V
a
³ 2 D U
U
k
Chosen
U = 200 V
k
+ 2 R ) I
2 L 2
a
(solidly grounded star-point)
2N
(impedance grounded star-point)
2N
D U
a
I
I (I results from I
S 2 2
= D -
2 2 U ( U U
k i k
1000/1 A
100 m
= . W
0 5
2
´
mm
2
)
= 0.2 ; x = x
2 T T0
1
=
, 10 A
1000
= 120 V
a
)
F
)
= 0.1 ; x = x
sys
ABB Switzerland Ltd
= 0.01
sys 0
4-7