ABB REG316 4 Series Operating Instructions Manual page 171

REG 316*4 1MRB520049-Uen / Rev. F
Note:
Because of the voltage drop of the v.t's, the voltage does not
reach 520 V at the full E/F current, but only 360 V. The setting of
the protection must therefore be modified as follows:
Overvoltage setting
360
=
0 05 . 0 034 .
520
Example 5
U = 27 kV; U
GN HV
HV system solidly grounded
I = 15 A
E
U
27000
= =
U GN
1 n
3 3
27000 æ
³
R ç
è
e min
´
3 15
0 05 27
£
R
e max
´ ´ ´
6 314 3 10
I = 250 A (chosen)
e
15
=
U 15600
2 n ´
3 300
The resistor R is chosen according to R
e
= 27 ´ 10 ´ 260
R -6
e
= 1.825 ´ 300 = 547 V
R I
e e
= 3 ´ 260 = 780 V
3 U
2n
S = 3 ´ 260 ´ 300 = 135 ´ 10
The specification and the modification of the protection setting is
similar to Example 4.
(3.4 % U
N
= 400 kV; C = 3 x 10
12
=
15600 V
2
3 U ö
2 n -
÷ = ´
27 10
ø
15600
´ 3 U
. æ
ç
400 è
15600
- 9
´
6
=
260 V
= 1.825 W
2
3 VA
ABB Switzerland Ltd
instead of 5 % U )
N
-9 F; x = 314 1/s
2
6
´
U
2 n
2
ö
-
2 n 6
÷ = ´ ´
132 10
ø
:
emin
2
U
2 n
3-133