Abstract: An arc fault detection unit is disclosed for a low-voltage electrical circuit. The arc fault detection unit includes at least one voltage sensor, for periodically determining electrical voltage values of the electrical circuit, connected to an evaluation unit. The evaluation unit is designed such that a first half of a first number of voltage values is continuously summed to form a first partial sum and the second half of the voltage values is continuously summed to form a second partial sum and a difference of the two partial sums is calculated. Either as one alternative the difference or the amplitude of the difference is compared with a first threshold value and if the value is exceeded, an arc fault detection signal is output; or as a second alternative the difference is compared with a second threshold value and if the value is undershot, an arc fault detection signal is output.

Abstract: An arc fault detection unit for an electrical low-voltage circuit, includes at least one voltage sensor assigned to the circuit, for periodically determining electrical voltage values of the circuit, and at least one current sensor assigned to the circuit, for periodically determining electrical current magnitudes of the circuit, both of which are connected to an evaluation unit. The sensors being embodied such that value pairs, having a voltage value and a current magnitude are determined continuously, a value set including a plurality of value pairs. Further, an arc voltage, compared to a first threshold value, is calculated from three value sets and in response to the first threshold value being exceeded, an arc fault detection signal is output.

Abstract: A method is disclosed for selectively triggering circuit breakers in the event of a short circuit, wherein an upstream circuit breaker and at least one downstream circuit breaker on the output side are provided. In at least one embodiment, the upstream circuit breaker monitors as to whether the or one of the downstream circuit breakers is already in the process of opening the switch contacts thereof to interrupt the circuit on the output side, while forming a switch arc. In order to reliably determine whether a downstream circuit breaker is already in the process of opening, according to at least one embodiment of the invention the upstream circuit breaker, so as to detect a switch arc on the output side, checks whether the ohmic resistance of the short circuit loop produced by a short circuit has an exponential curve over time in that an exponent is continually computed and based on the computer exponent the switch arc is determined if the computed exponent exceeds a threshold.

Abstract: A method is disclosed for selectively triggering circuit breakers in the event of a short circuit, wherein an upstream circuit breaker and at least one downstream circuit breaker on the output side are provided. In at least one embodiment, the upstream circuit breaker monitors as to whether the or one of the downstream circuit breakers is already in the process of opening the switch contacts thereof to interrupt the circuit on the output side, while forming a switch arc. In order to reliably determine whether a downstream circuit breaker is already in the process of opening, according to at least one embodiment of the invention the upstream circuit breaker, so as to detect a switch arc on the output side, checks whether the ohmic resistance of the short circuit loop produced by a short circuit has an exponential curve over time in that an exponent is continually computed and based on the computer exponent the switch arc is determined if the computed exponent exceeds a threshold.

Abstract: A method and a device for determining a switching time of an electric switching device. An electric switching device includes an interrupter link. A first line section and a second line section can be connected and disconnected by way of the interrupter link. In order to determine a switching time, the temporal progression of a driving voltage is determined in the first line section. In addition, a temporal course of an oscillator voltage appearing in the second line section is determined. Potential switching times are determined at the voltage zero crossings of a resulting voltage. The selection of the potential switching times ensues while evaluating the rises of the driving voltage and of the oscillator voltage or of the polarity of the oscillating current.

Abstract: According to the invention, a controlled or synchronous switching of an electrical power breaker (1) can be guaranteed by means of predicting a future voltage and/or current curve from actual voltage and/or current data in an electrical energy network (5). The prediction of the future voltage and/or current curve is carried out using the voltage and/or current data determined in the electrical network (5) at different timepoints by application of a Prony method to the available voltage and/or current data.

Abstract: A method and a device for determining a switching time of an electric switching device. An electric switching device includes an interrupter link. A first line section and a second line section can be connected and disconnected by way of the interrupter link. In order to determine a switching time, the temporal progression of a driving voltage is determined in the first line section. In addition, a temporal course of an oscillator voltage appearing in the second line section is determined. Potential switching times are determined at the voltage zero crossings of a resulting voltage. The selection of the potential switching times ensues while evaluating the rises of the driving voltage and of the oscillator voltage or of the polarity of the oscillating current.

Abstract: According to the invention, a controlled or synchronous switching of an electrical power breaker (1) can be guaranteed by means of predicting a future voltage and/or current curve from actual voltage and/or current data in an electrical energy network (5). The prediction of the future voltage and/or current curve is carried out using the voltage and/or current data determined in the electrical network (5) at different timepoints by application of a Prony method to the available voltage and/or current data.