ABB REG316 4 Series Operating Instructions Manual page 166

ABB Switzerland Ltd
Generator
U
GN
I E
I E
U /U
U
1n 2n 3n
3 C
R
e
I E e I
Fig. 3.5.11.5 Stator E/F protection with a grounding
transformer at the star-point
Example 2
U = 12 kV; I = 10 A
GN C
I = I = 10 A
Emax C
12000
= =
U 6930
n 1
3
I = 10 A
1n
U = 200 V
2n
I = I = 10
2n e
2
200
=
R
e ´
6930 10
= 6930 ´ 10 ³ 70 kVA
S = U I
n 1n 1n
Specification:
1 grounding transformer 70 kVA; 10 s;
6930/200 V;
1 resistor 0.577 W ;
1 interposing v.t.
(only necessary if U
3-128
REG 316*4 1MRB520049-Uen / Rev. F
LV
1
/U
4n
U>
V
6930
=
346 A
200
= W
0 577 .
10/346 A
346 A; 10 s
10 VA; 50 Hz; 200/100 V
> 100 V)
2n
Step-up transformer
HV
2
U
3 C
12
HEST 905 032 C
50 Hz
HV