Parallel Configuration - Siemens SINAMICS G130 Engineering Manual

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 level
k2 Line
Line reactors must always be provided if more than one rectifier is connected to the same point of common coupling.
In this instance, 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
rectifier must be provided with its own line reactor, i.e. it is not permissible for more than one rectifier to be connected
to the same line reactor.
A line reactor must also be installed for any rectifier that is to be equipped with a line filter for RI suppression. 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 rectifiers where these are
connected to a common power supply point. This generally applies to 6-pulse connections. The line reactors provide
for balanced current distribution and ensure that no individual rectifier is overloaded by excessive current imbalances.

Parallel configuration

SINAMICS S120 Cabinet Modules are designed in such a way that standard devices can be operated in a parallel
connection at any time. A maximum possible configuration of up to four identical modules can be operated in a
parallel connection for the purpose of increasing their output power.
As a result of potential imbalances in the current distribution, the derating factors given below may apply.
Since the possibility of imbalances in current distribution cannot be completely precluded in parallel connections of
Cabinet Modules, the derating factors for current or output need to be taken into account when parallel connections
are configured:
Designation
Active Line Modules
Basic Line Modules
Smart Line Modules
Motor Modules Chassis
It is not permissible to operate a mixture of Line Modules.
Modules in a parallel connection must all have the same voltage and output power rating. Further supplementary
conditions to parallel-connected Motor Modules must be taken into account when the system is configured (see
section "Motor Modules"). The parallel configuration of booksize units is not possible.
Power units connected in parallel are controlled by a common Control Unit via DRIVE-CLiQ. The separate ordering of
DRIVE-CLiQ cables which establish the connections between the paralleled cabinet units must be considered
(please see section "DRIVE-CLiQ wiring").
at the PCC of the Basic Line Module is approximately
k1
Derating factor for parallel connection
of 2 to 4 modules
0.95
0.925
0.925
0.95
SINAMICS S120 Cabinet Modules
Engineering Information
Max. permissible number of parallel-
connected modules
4
4
4
4
SINAMICS Engineering Manual - May 2008
255/396
© Siemens AG