Parallel Connection Of Smart Line Modules - Siemens SINAMICS S120 Function Manual

Function modules
8.10 Parallel connection of power units
8.10.1.2

Parallel connection of Smart Line Modules

Smart Line Modules are infeed/regenerative feedback units. Like the Basic Line Modules,
they supply energy to the connected Motor Modules, but unlike the Basic Line Module, they
are capable of feeding back regenerative energy to the line supply.
The DC-link voltage is greater than the rms value of the line rated voltage by a factor of 1.3.
Smart Line Modules in chassis format are suitable for connection to grounded (TN, TT) and
non-grounded (IT) supply systems. The following voltages and power ratings are available:
Table 8- 8
Line supply voltage
380 to 480 V 3 phase AC
500 to 690 V 3-phase AC
The following rules must be observed when connecting Smart Line Modules in parallel:
● Up to four identical Smart Line Modules can be connected in parallel.
● A common Control Unit must always be used to implement the parallel connection.
● A 4% reactor is always required upstream of each Smart Line Module for the purpose of
current balancing.
● Special Line Connection Modules are available for the parallel connection.
● With multiple infeeds, power must be supplied to the systems from a common infeed
point (i.e. the modules cannot be operated on different line supplies).
● A derating factor of 7.5% must be taken into consideration, regardless of the number of
modules connected in parallel.
6-pulse parallel connection of Smart Line Modules
With the 6-pulse parallel connection, up to four Smart Line Modules are supplied by a
common two-winding transformer on the line side and synchronously controlled by a
common Control Unit.
As Smart Line Modules have no current compensation control, the current must be balanced
by the following measures:
● Use of suitable line reactors for the Smart Line Modules.
● Use of symmetrical power cabling between the transformer and the parallel-connected
Smart Line Modules (cables of identical type with the same cross-section and length).
● The current reduction (derating) from the rated value for individual Smart Line Modules in
a parallel connection is 7.5%.
12-pulse parallel connection of Smart Line Modules
For 12-pulse parallel connections, up to four Smart Line Modules are supplied by a three-
winding transformer on the line side. In this case, an even number of modules, i.e. two or
four, must be divided between the two secondary windings. In contrast to Basic Line
Modules, the Smart Line Modules of both subsystems have to be controlled by two Control
Units due to the 30° phase displacement in the input voltages.
526
Smart Line Modules
Rated power
250 ... 800 kW
450 ... 1400 kW
Function Manual, (FH1), 04/2014, 6SL3097-4AB00-0BP4
Drive functions