Siemens SINAMICS G130 Engineering Manual page 46

Fundamental Principles and System Description
Engineering Information
The harmonic effects on the supply system associated with the Active Infeed are very low due to the combination of
Clean Power Filter and the IGBT inverter which is clocked with a pulse frequency of a few kHz.
In contrast to 6-pulse and 12-pulse rectifier circuits, the harmonics associated with the Active Infeed are both even
and odd. Each individual harmonic current and voltage is less than 1 % of the rated current and rated voltage
respectively with an Active Infeed.
The total distortion factors of current THD(I) and voltage THD(V) are given in the following table and indicate – in
exactly the same way as the individual harmonics – only a very minor dependence on the supply system conditions.
Supply system with high relative short-
circuit power (RSC >> 50):
"Strong supply system"
Supply system with average relative short-
circuit power (RSC = 50)
Supply system with low relative short-circuit
power (RSC = 15)
"Weak supply system"
Total distortion factors THD(I) and THD(V) with Active Infeed as a function of the system short-circuit power
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Total distortion factor current
THD(I)
< 4.1 %
< 3.0 %
< 2.6 %
Total distortion factor voltage
THD(V)
< 1.8 %
< 2.1 %
< 2.3 %