Commissioning - Siemens SINAMICS S120 Function Manual

Function modules
7.12 Master/slave function for Active Infeed
7.12.5

Commissioning

Line supply and DC link identification routine
Before the option "Master/slave" operation is enabled in STARTER, the line supply and DC
link identification runs (see corresponding section in this function manual) must be executed
during commissioning for each infeed train.
Please follow the instructions given in the commissioning manual for the commissioning of
infeeds.
Once each individual infeed has been identified, the correct inductance for current control
and the DC link capacitance for voltage control are set.
If a DC breaker for isolating the infeed from the DC link is installed, DC link identification
must be performed again for all active infeeds after one has been disconnected, as it is
necessary to acquire the DC link capacitance again. If the DC link capacitance is not
adjusted by this method, the change in capacitance will affect the dynamic response of the
V
DC-link
Activation of the master/slave function
The "Master/slave" function is activated with the checkbox/option "Master/Slave" in the
STARTER wizard for the relevant infeed. Parameter r0108.19 can be used to scan for an
active function module in the CU or the Active Line Modules (r0108.19 = 1).
All other required parameters are set via the corresponding expert lists for the relevant
infeed.
Note
The bus cycle time for Active Line Modules operating in master-slave operation must not
exceed 2 ms, or else the dynamic response (p3560) will need to be severely reduced. This
means that load surges can no longer be corrected properly.
Increasing the bus cycle time can cause the DC link voltage to oscillate, an effect which can
sometimes be managed by reducing the dynamic response (p3560). The system cannot be
guaranteed to function reliably with bus cycle times of > 2 ms.
The Vdc setpoint in p3510 must be set high enough to prevent the standby controller from
responding to line overvoltage (the response threshold of 97% can be increased if
necessary, but current and voltage harmonics will develop if the setting causes overdrive).
In any case, the tolerance band must be set wide enough that it will not be violated should
the control factor reserve controller still respond because the measures described above
have not been implemented.
Master/slave switchover
If a power unit fails during operation, the higher-level controller can switch each infeed train
from current control (slave operation) to DC link voltage control (master operation) and vice
versa (parameter setting for master: p3513= 0, for slave: p3513=1).
344
control.
Function Manual, (FH1), 10/2008, 6SL3097-2AB00-0BP5
Drive functions