ABB REG316 4 Series Operating Instructions Manual page 279

REG 316*4 1MRB520049-Uen / Rev. F
Design example:
=
U 18 kV
Gen
N 14.4 kV
1
= =
60
N 240 V
2
Assumed: I £ 6.6 A
Emax
Determination of the grounding resistors:
+
Condition 1: R' R'
Es
³
Condition 2: R'
Ps
=
Assumed: R' 42 m
Ps
³
Condition 3: R'
Es
³
Condition 4: R'
Es
In order to fulfil Conditions 1, 3 and 4:
= W
R' 400 m
Es
Determination of the v.t.:
N'
12
=
Assumed:
N'
11
Condition 5 is fulfilled because:
N'
12
´ ³ ³
1.2 n
N'
11
18 kV
=
where n
´
3
The following values are permissible:
W
R' = 42 m
Ps
W
R' = 400 m
Es
=
N N 173 V 100 V
12 11
18 kV
æ
³ ´
ç
Ps
è
´
3 6.6 A
2
1
æ ö
W ´ ÷ =
130 36 m
ç
è ø
60
W
´ W =
4.5 42 m 189 m
2
1
æ ö
W ´ ÷ =
700 194 m
ç
è ø
60
18 kV 1 173.2 V
´ =
´
3 100 V 60
´ ³
0.8 n = 1.88 1.732 1.254
1 400 m
´ ´
60 400 m
100 V
ABB Switzerland Ltd
2
1
ö
÷ = W
440 m
ø
60
W
W
W
=
3
100 V
³
W
=
1.567
W + W
42 m
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