Abstract: A device for detecting alternating-current components iAC of an electric current iACDC flowing in a direct-current circuit includes an inductor arranged in the direct-current circuit, and an AC path arranged electrically in parallel with the inductor, wherein the AC path comprises a series circuit made up of a capacitor and a primary winding of a transformer. The device further includes a voltage measuring device, wherein a secondary winding of the transformer is connected to the voltage measuring device via a low-pass filter circuit.

Abstract: The method of detecting an arc fault in a power circuit includes determining a first signal related to current flowing in the power circuit is determined and analyzing the first signal to determine whether the signal indicates the presence of an electric arc in the power circuit. In case the first signal indicates the presence of an electric arc in the power circuit, means for suppressing an electric arc are activated. A second signal related to current flowing in the power circuit is then determined and analyzed. An occurrence of an arc fault in the power circuit is signaled if the second signal does not indicate the presence of an electric arc. The system for detecting an arc fault is designed to perform a corresponding method.

Abstract: A method for detecting an arc fault in a photovoltaic power circuit includes operating a photovoltaic generator at a first working point. A first signal related to a DC-current and/or a DC-voltage in the power circuit is determined. The first signal is analyzed and it is determined whether the signal indicates the presence of an electric arc in the power circuit. If so, the photovoltaic generator is operated at a second working point and a second signal related to the DC-current and/or the DC-voltage is determined. The first and second signals are then compared; and the occurrence of an arc fault in the power circuit is selectively signaled based on the comparison.

Abstract: The disclosure relates to a method for localizing and quenching an arc in a PV generator of a PV system, wherein the PV generator includes at least two PV subgenerators. An arc quenching circuit is associated with each PV subgenerator. The method includes detecting an arc in the PV generator. Then, a probability value is determined for each of the PV subgenerators, wherein the probability value is correlated with a probability that the arc is located in the corresponding PV subgenerator. A sequence for activating the arc quenching circuits is then determined that is dependent on the determined probability values. Then, the arc quenching circuits are activated successively in the order of the determined sequence.

Abstract: The disclosure relates to a method for detecting an arc in a DC circuit. The method includes measuring and analyzing an AC component (IAC) of a current (I) flowing in the circuit and determining at least one parameter of the AC component (IAC). The level of a DC component (IDC) of the current (I) is varied and a degree of correlation between the level of the DC component (IDC) of the current (I) flowing in the DC circuit and the at least one parameter of the AC component (IAC) is determined. An arc is detected and selectively signaled based on the degree of the determined correlation. The disclosure also relates to an apparatus for carrying out the method and to an inverter comprising such an apparatus.

Abstract: A method for detecting an arc fault in a photovoltaic power circuit includes operating a photovoltaic generator at a first working point. A first signal related to a DC-current and/or a DC-voltage in the power circuit is determined. The first signal is analyzed and it is determined whether the signal indicates the presence of an electric arc in the power circuit. If so, the photovoltaic generator is operated at a second working point and a second signal related to the DC-current and/or the DC-voltage is determined. The first and second signals are then compared; and the occurrence of an arc fault in the power circuit is selectively signaled based on the comparison.

Abstract: A method of detecting an arc fault in a power circuit includes injecting an AC-signal into the power circuit and measuring a response signal that is related to the injected AC-signal in the power circuit. The method further includes determining a frequency response of the power circuit from the response signal, analyzing the frequency response, and identifying a preferred frequency. A signal related to AC-current flowing in the power circuit within the preferred frequency range is measured and an occurrence of an arc fault in the power circuit is signaled depending on the measured signal. A system for detecting an arc fault is designed to perform a method as described before.

Abstract: The method of detecting an arc fault in a power circuit includes determining a first signal related to current flowing in the power circuit is determined and analyzing the first signal to determine whether the signal indicates the presence of an electric arc in the power circuit. In case the first signal indicates the presence of an electric arc in the power circuit, means for suppressing an electric arc are activated. A second signal related to current flowing in the power circuit is then determined and analyzed. An occurrence of an arc fault in the power circuit is signaled if the second signal does not indicate the presence of an electric arc. The system for detecting an arc fault is designed to perform a corresponding method.

Abstract: The disclosure relates to methods for sequentially disconnecting at least two electrical current sources from a common load or for sequentially connecting the current sources to a load, wherein the current sources are each connected to the common load via a switching unit, each comprising a parallel circuit comprising an electromechanically actuated switch and an associated semiconductor switch. In the two methods, first semiconductor switches are closed if they are still not closed and the relevant electromechanical switches are opened. In the method for sequential disconnection, then at least two of the semiconductor switches that were actuated or that were already closed are opened sequentially. In the method for sequential connection, a plurality of the semiconductor switches are first opened, of which then at least two are closed sequentially. The disclosure also relates to a photovoltaic system comprising an apparatus that is suitable for implementing the method.