With a high line short-circuit power (i.e. low line supply cable inductance) a line reactor is required in order to

• protect the drive converter itself from excessively high harmonic currents and therefore overload
• limit the harmonics to permissible values. The harmonic currents are limited by the complete inductance comprising the line reactor and line supply cable inductance.

For additional information, please refer to the SINAMICS Low Voltage Engineering Manual.