Sma Solar Technology Ag

Thorsten Buelo

Gerd Bettenwort

Markus Hopf

Marcel Kratochvil

Oliver Prior

Claus Allert

Holger Behrends

Daniel Premm

Sebastian Bieniek

Vitali Sakschewski

Christopher Merz

Stijn Stevens

Denis Mende

Yehia Tarek Fawzy

Florian Rauscher

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. The method includes measuring delta voltages and phase voltages and phase angles at the low-voltage side of the transformer, transforming the phase voltages and phase angles into positive and negative phase sequence system voltages and phase angles of the positive and negative phase sequence systems, respectively, at the low-voltage side, determining positive and negative phase sequence system voltages and phase angles of the positive and negative phase sequence systems, respectively, at the high-voltage side from the positive and negative phase sequence system voltages and phase angles of the positive and negative phase sequence systems, respectively, at the low-voltage side, determining estimated values of a zero phase sequence system voltage and of a phase angle of a zero phase sequence system at the high-voltage side from the measured delta voltages and phase voltages and phase angles at the low-voltage side, and transforming the positive, negative and zero phase sequence system voltages and the phase angles into phase voltages and/or delta voltages at the high-voltage side of the transformer.

Method and device for approximately determining voltages at a high-voltage side of a transformer

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. The method also includes, in night-time operation, deactivating all the inverters of a group with the exception of the first inverter and feeding in reactive power by the first inverter depending on the second parameter, wherein the reactive power fed in corresponds to a magnitude of a reactive power drawn by the respective underlying second coupling impedance.

Method for minimizing a network feedback of a PV park, inverter, and PV park

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.

Grid diagram creation and operation control

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.

Method and system for detecting an arc fault in a photovoltaic power system

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