Siemens SINAMICS G130 Engineering Manual page 57

Fundamental Principles and System Description
Engineering Information
Range B
Range B comprises supply voltage dips, the magnitude of which reaches values of V /V ≈ 0.5. As a result of the
Line N
regulated operation, the DC link voltage can be maintained at its pre-set value, as long as the reduced supply voltage
can be compensated for with an increased input current. The auxiliaries supplied with 230 V via the internal
transformer, do not, however, remain in operation.
Dips in range B are, therefore, only permissible when the supply of the auxiliaries with 230 V is done via a secure,
external source. It must also be taken into consideration that the DC link voltage and the drive power decrease in
proportion to the magnitude of the supply voltage dip.
Since the modulation depth of the Active Infeed alters significantly during deep supply voltage dips at the lower end
of range B by comparison with normal operation, the harmonic effects on the supply system increase and the Clean
Power Filter in the Active Interface Module AIM of the Active Infeed is also subjected to a higher thermal load. For
these reasons, operation at the lower end of range B is permissible for only a few minutes.
Range C
Range C comprises very short supply voltage dips of any magnitude, the duration of which is up to 5 ms. During this
time, the current required by the load is mainly delivered by the DC link capacitors, thus causing the DC link voltage
to decrease. Due to the extremely short duration, the DC link voltage does not reach the under-voltage trip level,
even at 100 % load. The auxiliaries supplied with 230 V also remain in operation.
Dips in range C are, therefore, as a result of the extremely short duration, permissible without restrictions.
Range D
Range D comprises very short supply voltage dips of any magnitude, the duration of which is up to 10 ms. During this
time, the current required by the load is mainly delivered by the DC link capacitors, thus causing the DC link voltage
to decrease. The DC link voltage then only does not reach the under-voltage trip level, if the DC link is discharged
more slowly than in range C. Therefore, the drive can be operated with a maximum load of 50 %. Due to the relatively
short duration, it can be assumed that the auxiliaries supplied with 230 V will remain in operation.
Dips in range D are, therefore, as a result of the very short duration, permissible, as long as the drive is operating at
partial load with a maximum of 50 % load.
Range E
Range E comprises short supply voltage dips of any magnitude, the duration of which is up to 50 ms. During this
time, the current required by the load is mainly delivered by the DC link capacitors, whereby the DC link voltage
decreases. The DC link voltage then only does not reach the under-voltage trip level, if the DC link is discharged
more slowly than in range D. Therefore, the drive can only be operated with no load. The auxiliaries, which are
supplied with 230 V directly from the supply via the internal transformer, do not remain in operation.
Dips in Range E are, therefore, only permissible if the auxiliaries are supplied from a secure, external supply and the
drive is in no-load operation.
Range F
Range F comprises supply voltage dips, the magnitude and duration of which is so large, that, independently of the
load, a fault trip due to under-voltage in the DC link cannot be avoided.
Dips in range F are, therefore, not permissible.
Note:
The statements – particularly the time specifications – regarding ranges C to E are precisely accurate only in relation
to single drives (e.g. for SINAMICS G150). In the case of multi-motor drives, the specified times might be much
longer depending on the drive constellation and operating conditions. This might be true, for example, if inverters
which are in standby mode during normal operation but raise the DC link capacitance of the drive configuration, are
connected to the DC busbar of the drive configuration. The times can also be significantly longer in DC drive
configurations in which some of the drives operate in motor mode and others in generator mode. These influencing
factors mean that no generally valid statements can be made about multi-motor drives and each drive configuration
must therefore be assessed individually.
Summary of the drive behaviour during supply voltage dips
If one considers the behaviour of the unregulated and regulated SINAMICS Infeeds and also reflects upon the typical
distribution of supply voltage dips as shown in the diagram in the section "Suppy voltage variations and supply
voltage dips", the following conclusions can be drawn.
Extremely large dips as those in the ranges C to E, during which the supply voltage dips to almost zero and the
energy flow from the supply to the DC link is essentially interrupted, can only be tolerated absolutely reliably,
independently from the kind of Infeed, for a time period of approximately 5 ms to a maximum of 50 ms, depending on
the load condition, because the energy stored in the DC link capacitors is very low. However, dips of such magnitude
and duration very rarely occur in practice.
SINAMICS Engineering Manual – November 2015
57/528
Ó Siemens AG