Abstract: The disclosure relates to a method and related device for approximately determining voltages at a high-voltage side of a transformer on the basis of measured voltages at a low-voltage side of the transformer.

Abstract: The disclosure relates to a method and related device for approximately determining voltages at a high-voltage side of a transformer on the basis of measured voltages at a low-voltage side of the transformer.

Abstract: A method and associated system for minimizing grid feedback of a PV park to an energy supply grid connected to a point of common coupling is disclosed, wherein the PV park has a plurality of inverters divided into groups. The method includes, for at least a first inverter of each group, determining a first parameter representative of a first coupling impedance between the first inverter and the point of common coupling and determining a second parameter representative of a second coupling impedance between the group containing the first inverter and the point of common coupling. The method further includes storing the first parameter and the second parameter in an operating control unit of the first inverter, and, in daytime operation of the PV park, feeding in reactive power by the first inverter depending on the first parameter, said reactive power corresponding to the magnitude of a reactive power drawn by the respective underlying first coupling impedance.

Abstract: For determining the topology of a grid section of an AC power grid, the grid section comprising a grid connection point, at least one branch branching off from the grid connection point and including a plurality of energy consumption and/or energy generation units, and at least one measurement point in the at least one branch, dependencies of variations of a grid voltage measured at the at least one measurement point based on variations of connection power values of at least some individual ones of the energy consumption and/or energy generation units are determined.

Abstract: A method and associated system for minimizing grid feedback of a PV park to an energy supply grid connected to a point of common coupling is disclosed, wherein the PV park has a plurality of inverters divided into groups. The method includes, for at least a first inverter of each group, determining a first parameter representative of a first coupling impedance between the first inverter and the point of common coupling and determining a second parameter representative of a second coupling impedance between the group containing the first inverter and the point of common coupling. The method further includes storing the first parameter and the second parameter in an operating control unit of the first inverter, and, in daytime operation of the PV park, feeding in reactive power by the first inverter depending on the first parameter, said reactive power corresponding to the magnitude of a reactive power drawn by the respective underlying first coupling impedance.

Abstract: For determining the topology of a grid section of an AC power grid, the grid section comprising a grid connection point, at least one branch branching off from the grid connection point and including a plurality of energy consumption and/or energy generation units, and at least one measurement point in the at least one branch, dependencies of variations of a grid voltage measured at the at least one measurement point based on variations of connection power values of at least some individual ones of the energy consumption and/or energy generation units are determined.

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 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 present invention relates to a three-phase inverter (1) with a circuit arrangement having a DC-voltage input (2) for at least one direct voltage source, and a three-phase alternating voltage output (15) for feeding into a three-phase alternating voltage mains (19), wherein said inverter comprises a three-phase bridge circuit (20) as well as at least one divided intermediate circuit, wherein said inverter (1) is configured to be transformerless, wherein said neutral conductor (N) of the mains (19) is separated from the central point (M) of the intermediate circuit and the inverter (1) is connected to the alternating voltage mains (19) via a three-conductor connection (15).