Siemens SINAMICS S120 Function Manual page 328

Function modules
7.11 Parallel connection of power units
Smart Line Modules (SLM)
Features
Smart Line Modules are infeed/regenerative feedback units. Like the Basic Line Module,
they supply energy to the connected Motor Modules, but unlike the Basic Line Module, they
are capable of recovering energy to the supply network.
The DC link voltage is greater than the rms value of the line rated voltage by a factor of 1.3.
Smart Line Modules are suitable for connection to grounded (TN, TT) and non-grounded (IT)
supply systems. The following voltages and power ratings are available:
Line voltage / unit rating
380 ... 480 V 3 AC / 250 ... 800 kW
500 ... 690 V 3 AC / 450 ... 1400 kW
The following rules must be observed when connecting Smart Line Modules in parallel:
● Up to 4 identical Smart Line Modules can be connected in parallel.
● A shared Control Unit must be used to implement the parallel connection.
● A 4% reactor is always required upstream of each Smart Line Module for the purpose of
● Special Line Connection Modules are available for the parallel connection.
● With multiple infeeds, power must be supplied to the systems from a common infeed
● A derating factor of 7.5 % must be taken into consideration, regardless of the number of
6-pulse parallel connection of Smart Line Modules
With the 6-pulse variant of parallel connection, up to four Smart Line Modules on the line
side are supplied by a shared two-winding transformer and controlled by a shared Control
Unit.
As Smart Line Modules have no current compensation control, the current must be balanced
by the following measures:
328
current balancing.
point (i.e. the modules cannot be operated on different supplies).
modules connected in parallel.
Function Manual, (FH1), 10/2008, 6SL3097-2AB00-0BP5
Drive functions