Method and device for monitoring a three-phase network operated in a compensated manner for a tuning change of the arc suppression coil

A method for monitoring a three-phase power network operated in a compensated manner for a tuning change of an arc suppression coil, the method which comprises:

• ascertaining reference network parameters and a reference network frequency for a tuned state;
• ascertaining a current network frequency for a current state;
• determining a reference characteristic variable, which is proportional to a displacement voltage, using the reference network parameters for the current network frequency;
• determining a current characteristic variable, which is proportional to a displacement voltage, at the current network frequency;
• determining a differential variable from the reference characteristic variable and the current characteristic variable, and identifying a tuning change from the differential variable when a predetermined threshold value is exceeded, and ascertaining modified network parameters;
• and
• performing a tuning procedure to tune the arc suppression coil based on the modified network parameters ascertained.