Dynamic Grid Support - Siemens SINAMICS S120 System Manual

Detailed descriptions of the function modules
6.1 Additional closed-loop controls for current-controlled operation
Figure 6-1 Additional modules for current-controlled operation
6.1.2

Dynamic grid support

Background
A parameterizable characteristic allows a reactive current to be specified corresponding to
the deviation of the grid voltage from its rated value. This is specified in many grid codes.
The background to this requirement is the inductive behavior of a grid inverter, whose most
simple equivalent circuit diagram comprises a series circuit of a controlled voltage source
and inductance L. Different voltage levels between the grid inverter and grid result in current
flowing in the reactive axis due to
I = (U
b
50
- U )/jωL
grid inv
System Manual, 04/2015, A5E03347436A
Grid infeed