Siemens SINAMICS S120 System Manual page 46

Function modules
5.3 Description of the function modules
Note
Definition, displacement factor cosφ
Displacement factor cosφ is also defined as the cosine of the phase angle φ between the
sinusoidal oscillations of the voltage and the current having the same frequency. For a more
precise designation, an index is therefore added corresponding to the particular frequency or
harmonic number.
The VSM10 measures voltages and currents, so that these variables (and not power) are
used as input signals for the cosφ display.
Note
Defining the sign
The definition of the sign as generating unit matches the use in the grid standards (e.g. VDE-
AR-4105).
• For underexcited operation (negative reactive current: r0076 < 0) the following applies:
Lower output voltage or lagging current is designated with a positive sign.
• For overexcited operation (positive reactive current: r0076 > 0) the following applies:
Higher output voltage or leading current is designated with a negative sign.
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System Manual, 04/2015, A5E03347436A
Grid infeed