Siemens SINAMICS S110 Manual page 59

TT system
In a TT system, a point of the generator or the transformer is grounded, normally the neutral
point. The housing of the consumer is connected with the ground using a separate cable.
Figure 3-13
● Power Modules without a line filter can be operated on all TT systems.
● Power Modules with an integrated or external line filter can be operated only in TT
systems with a grounded neutral point.
IT system
In an IT system, the voltage network is either not connected with ground or connected only
using a high-resistance impedance. The housing of the consumer is connected with the
ground using a separate cable.
Figure 3-14
● Power Modules without a line filter can be operated in all IT systems.
● Power Modules with an integrated or external line filter can be operated only in IT
systems.
SINAMICS S110
Manual, 07/2015, 6SL3097-4AC10-0BP5
TT system
IT system
Mains connection and line-side power components
3.9 Line connection variants
59