ABB DCS 400, Manual

Page: 108 / 192

II K 5-8
Installation
Due to the maximum power of public 400 V transformers
(P
MAX
= 1.2 MVA
Õ
I
MAX
= 1732 A) and due to their relative short circuit
voltage V
SC
of 6% or 4% the maximum AC current which is available for a
converter is 346 A or 520 A (I
DC
≤
422 A or 633 A).
For v
SC
= 4 %: I
DC
≤
633 A
For v
SC
= 6 %: I
DC
≤
422 A
X
PCC
Converter
Supply transformer of a residental region with light industry
(rated power normally
≤
1.2 MVA). With reference to EN
61800-A11 the rated power of transformer must be at least
4 times the rated power of the PDS.
Earthed public 400 V
line with neutral
conductor
Earthed
star point
Medium-voltage line
Line choke
PCC
Notches
≤
20 %
v
SC
= 4 % or 6 %
I
max
= 1.7 kA
For v
SC
= 4 %: X
PCC
≥
5.40 m
Ω
(L
PCC
≥
17.2 µH)
For v
SC
= 6 %: X
PCC
≥
8.12 m
Ω
(L
PCC
≥
25.8 µH)
For v
SC
= 4 %: X
CHOKE
≥
4
x
X
PCC
= 21.6 m
Ω
(L
CHOKE
≥
68.8 µH)
For v
SC
= 6 %: X
CHOKE
≥
4
x
X
PCC
= 32.48 m
Ω
(L
CHOKE
≥
103.2 µH)
Example:
2
*
QRP
QRP3&&
6& 3&&
3
9
Y ; ≥
% 20
≤
+
&+2.( 3&&
3&&
; ;
;
3&& &+2.(
; ;
* 4
≥ ⇒
Figure 5.2 - 3 Required minimum line choke impedance for
installation of converter in first environment
Often the maximum current is not limited by the transformer but by the
power cable to the industry region. Therefore it is necessary to ask the
energy supply company concerning the line impedance and the current
which is available at the desired point of common coupling (PCC).