Identification Of The Transformer Data; Line Filter And Transformer Monitoring; Function Module For Grid Droop Control - Siemens SINAMICS S120 System Manual

5.3.1.2

Identification of the transformer data

The main and leakage inductance of the transformer are identified – together with the phase
shift and the voltage correction.
5.3.1.3

Line filter and transformer monitoring

As already described, network connection regulations stipulate the provision of short-circuit
current during short-term short-circuits in the power grid. Short-circuits within the power
generation system (between the inverter and the network connection point) however must
result in an immediate shutdown to prevent additional damage to the system.
With the aid of the line filter and transformer monitoring function, a distinction/detection is
carried out for external line short-circuits (requiring grid support) and internal short-circuits
that result in a safety shutdown.
5.3.2

Function module for grid droop control

Task
In normal operation, the Active Line Module acts as a grid support by injecting sinusoidal line
currents. The function module "Grid droop control" also enables grid former operation, i.e.
the line voltage and line frequency are controlled instead of the DC link voltage and the
reactive current. Droop characteristic curves using a stable network operation is possible
with other generators (e.g. diesel generators) in an island grid without further communication
connection.
Using this function module, an Active Line Module is in a position to establish island grids,
operate them so that they remain stable (as single grid former – or together with other
generating units), and when required, to synchronize with external grids.
Grid infeed
System Manual, 04/2015, A5E03347436A
Function modules
5.3 Description of the function modules
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