Abstract: A device for compensating a line fault occurring on a three-phase power supply grid includes a transformer with a neutral point which is designed to generate a network voltage and thus a neutral-point displacement voltage. A measurement and control device is configured to detect the network voltage or the neutral-point displacement voltage and on that basis to identify an occurring line fault and to determine a control variable for compensating the line fault. A converter circuit is configured to generate a control current from the control variable and to feed in the control current at the neutral point of the transformer to compensate the line fault. The measurement and control device is also configured to determine a boost line value, and on that basis to determine a boost function, to generate a corresponding boost current, and to feed same in at the neutral point of the transformer.

Abstract: A method for monitoring a three-phase network that is operated in a compensated manner for a tuning change of the arc suppression coil. Reference network parameters and a reference network frequency are determined for a tuned state, and a current network frequency is determined for a current state. A reference characteristic variable, which is proportional to a displacement voltage, is determined for the current network frequency using the reference network parameters, and a current characteristic variable, which is proportional to a displacement voltage, is determined at the current network frequency. A differential variable is determined from the reference characteristic variable and the current characteristic variable, from which, with a predetermined threshold value being exceeded, a tuning change is identified and changed network parameters are determined.

Abstract: A device for compensating a line fault occurring on a three-phase power supply grid includes a transformer with a neutral point which is designed to generate a network voltage and thus a neutral-point displacement voltage. A measurement and control device is configured to detect the network voltage or the neutral-point displacement voltage and on that basis to identify an occurring line fault and to determine a control variable for compensating the line fault. A converter circuit is configured to generate a control current from the control variable and to feed in the control current at the neutral point of the transformer to compensate the line fault. The measurement and control device is also configured to determine a boost line value, and on that basis to determine a boost function, to generate a corresponding boost current, and to feed same in at the neutral point of the transformer.