SIEMENS
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Siemens D 11 · 2015
3
SINAMICS G130
Drive converter chassis units
Line-side power components > Line reactors
■
Overview
A line reactor is needed for high short-circuit power levels, partly
to protect the actual converter against excessive harmonic cur-
rents, and thus against overload, and partly to limit the line har-
monics to the permissible values. The harmonic currents are lim-
ited by the complete inductance comprising the line reactor and
line supply cable inductance. Line reactors can be omitted if the
line supply cable inductance is increased sufficiently, i.e. the
RSC value must be sufficiently small.
RSC = Relative Short-Circuit power: Ratio of short-circuit power
S
K line
at the supply connection point to fundamental apparent
output S
conv
of the connected converters (according to
IEC 60146-1-1).
The following applies for SINAMICS G130 converter built-in
units:
It is recommended that a line reactor is always connected on the
line side of the converter, as in practice, it is often not known on
which supply configuration individual converters are to be
operated, i.e. which supply short-circuit power is present at the
converter connection point.
A line reactor can only be omitted when the value for RSC is less
than the values listed in the above table. This is the case, when
the converter, as shown in the following figure, is connected to
the line supply via a transformer with the appropriate rating.
Notice:
However, a line reactor is always required when a line filter is
used.
In this case, the line short-circuit power S
k1
at the connection
point of the converter is approximately:
S
k1
=
S
transf
/ (
u
k transf
+
S
transf
/
S
k2 line
)
Power
Line reactor
can be omitted
Line reactor required
kW
For RSC
For RSC
<200
≤
43
>43
200 ... 500
≤
33
>33
>500
≤
20
>20
Connection point of the
converter
Mains supply cable
inductance
Converter
Line reactor
Line
S
k line
G_D011_EN_00023c
Formula symbols
Meaning
S
transf
Transformer power rating
S
k2 line
Short-circuit power of the higher-level voltage
u
k transf
Per-unit short-circuit voltage
u
Connection point of the
transformer
Connection point of the
converter
Mains supply cable
inductance
Converter
S
transf
k transf
%
Line
k1
k2 line
G_D011_EN_00022c
S
S
© Siemens AG 2015