Line Filters - Siemens SINAMICS G130 Engineering Manual

SINAMICS G150
Engineering Information
A line reactor can only be dispensed with (option L22) when the RSC value for relative short-circuit power is less than
stated in the above table. This applies, for example, if the converter is connected to the supply via a transformer with
specially adapted rating and none of the other reasons stated above for using a line reactor is valid.
Transformer connection
S
k2 Line
Supply
Supply cable
inductance
In this case, the short-circuit power S
S
=
Transf
S
k 1
S
+
Transf
u
k Transf
S
k 2 Line
Abbreviation Meaning
S Rated power of the transformer
Transf
u Relative short-circuit power of the transformer
k Transf
S Short-circuit power of the higher-level voltage
k2 Line
As high-output converters are usually connected to medium-voltage supply systems via transformers to reduce their
harmonic effects on the supply, cabinet units over 500 kW are not equipped with line reactors as standard. A line
reactor (option L23) is required for cabinet units with outputs > 500 kW only if the RSC ratio is > 20.
Line reactors must always be provided if more than one converter is connected to the same point of common
coupling. In this case, the reactors perform two functions, i.e. they smooth the line current and decouple the rectifiers
at the line side. This decoupling is essential in ensuring fault-free operation of the rectifier circuit. For this reason,
each converter must be provided with its own line reactor, i.e. it is not permissible for more than one converter to be
connected to the same line reactor.
A line reactor must also be installed for any converter that is to be equipped with a line filter for RFI suppression
(option L00) or with a Line Harmonics Filter (LHF) for reducing harmonic effects on the supply. This is because filters
of this type cannot be 100% effective without a line reactor.
Another constellation which requires the use of line reactors is the parallel connection of converters where the
paralleled rectifiers are connected to a common power supply point. This applies to parallel connections of G150
units which use a 6-pulse connection. Parallel connections of this type are therefore equipped as standard with line
reactors despite their high rated outputs of > 500 kW. The line reactors provide for balanced current distribution and
ensure that no individual rectifier is overloaded by excessive current imbalances.

Line filters

SINAMICS G150 cabinets are equipped as standard with an integrated line filter for limiting radio frequency
interference emissions in accordance with EMC product standard EN 61800-3, category C3 (applications in industrial
areas or in the "second" environment).
An optional line filter (option L00) is also available which renders the units suitable for category C2 applications in
accordance with product standard EN 61800-3 (installation in residential areas or in the "first" environment).
To ensure that the converters comply with the tolerance limits defined for the above categories, it is absolutely
essential that the relevant installation guidelines are followed. The efficiency of the filters as regards grounding and
shielding can be guaranteed only if the drive is properly installed. For further details, please refer to the section "Line
filters" of the chapter "Fundamental Principles and System Description".
SINAMICS Engineering Manual – May 2008
198/396
© Siemens AG
Converter connection
point point PCC
S S
Transf k1
u
k Transf
at the PCC of the converter is approximately
k1
Converter