ABB REG316 4 Series - Page 164

ABB Switzerland Ltd REG 316*4 1MRB520049-Uen / Rev. F
3-126
Example 1
U
GN
= 12 kV; U
HV
= 110 kV; C
12
= 3 x 10
-9
F; w = 314 1/s
I
Emax
£ 20 A
a) HV system ungrounded
R
Emin
³
´
=
12000
320
346
W
R
Emax
.
£
´
´´´ ´
=
-
005 12
6 314 3 10 110
965
9
W
Chosen R
E
= 750 W
I
U
R
A
E
GN
E
max
.==
´
=
3
12000
3 750
924
Specification:
1 grounding resistor 750
W; 10 A; 10 s
1 v.t.
12000
3
100/;V single-phase insulation
b) HV system solidly grounded
Only 1/6 of the voltage U
HV
is effective.
R
Emin
³
´
=
12000
320
346
W
R
Emax
.
£
´
´´´ ´
=
-
005 12
6 314 3 10
110
6
5790
9
W
Chosen R
E
= 3000 W
I
U
R
A
E
GN
E
max
.==
´
=
3
12000
3 3000
23
Specification:
1 grounding resistor 3000
W; 2.3 A; 10 s
1 v.t.
12000
3
100/;V single-phase insulation