Description, technical data 12.2010
16 ENGLISH Siemens AG 6RX1700-0DD74
SIMOREG DC-MASTER Converter Commutation Protector Operating Instructions
3 Description, Technical Data
3.1 Description
Application
The SIMOREG DC-MASTER Converter Commutation Protector (SIMOREG CCP) is used to
protect the semiconductor fuses of a line-commutated converter when operating in the inverter
mode. When an inverter commutation fault occurs, a high current flows in the regenerative
feedback direction via the line supply or a cross-current in the converter. SIMOREG CCP limits the
current to a non-hazardous value so that the thyristors and the associated super-fast fuses are
protected. This therefore eliminates the complex replacement of fuses that takes a considerable
amount of time. Although it cannot prevent inverter commutation faults, it can provide protection
against its effects.
Compatibility
The SIMOREG CCP is compatible to line-commutated SIMOREG DC-MASTER converters (from
software release 2.2) and SINAMICS DCM (from software release 1.2).
It can be used for converters connected in parallel.
Note
It is not possible to use the SIMOREG CCP for converters connected in series.
Mode of operation
The line supply voltage, line current and the armature voltage are continually sensed in the basic
converter unit. These quantities are used to identify as to whether a commutation fault (inverter
commutation fault) has occurred.
If this is the case, then the following occurs:
1. The firing pulses are immediately disabled in the SIMOREG DC-MASTER or SINAMICS DCM.
2. The basic converter unit sends a turn-off command to the SIMOREG CCP (via the serial
interface)
3. SIMOREG CCP turns-off the thyristors by connecting the pre-charged quenching capacitors
anti-parallel to all thyristors. As a consequence, the current commutates from the converter into
SIMOREG CCP. The quenching capacitors are initially discharged by the current that has been
commutated and then they are charged. The armature current starts to decrease as soon as the
voltage of the quenching capacitors has reached the value of the motor EMF. However, the
armature voltage continues to increase. As soon as it has reached the limit value, resistors are
switched-in, which absorb the energy fed back from the motor during the remaining time of the
current reduction phase.
4. A fault message is output in the basic converter unit (Fault F030 or F60030).
5. The SIMOREG CCP re-charges the quenching capacitors with the reverse polarity so that a
new turn-off operation is possible.
Note
After the line supply voltage has been connected and after a quenching operation, wait and recovery
times must be maintained, refer to the Technical data.
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