Sma Solar Technology Ag

Rainer Schmitt

Marcel Kratochvil

Raimund Thiel

Sybille Pape

Torsten Otto

A method for detecting an arc in a circuit including a DC load, a DC source supplying the DC load, and a circuit arrangement between the DC source and the DC load is provided. A power flow between the DC source and an output of the circuit arrangement is cyclically interrupted by a switching circuit, such that the power flow is enabled in an active time window with the first period Δtand suppressed in an inactive time window with the second period Δt. Detection of a current I and/or a voltage U in two consecutive active time windows and comparison of the detected values of current I and/or voltage U of the active time window with the corresponding detected values from the preceding active time window can signal an arc if these values of the active time window differ from the corresponding values of the preceding active time window by more than a threshold value.

Method and circuit arrangement for detecting an arc, and photovoltaic (PV) inverter having a corresponding circuit arrangement

The disclosure describes a method for detecting an arc in a direct-current (DC) circuit comprising a DC load, a DC source supplying the DC load, and a circuit arrangement arranged between the DC source and the DC load. A power flow P between an input and an output of the circuit arrangement is suppressed by means of a switching circuit through cyclical interruption such that the power flow P is enabled in an active time window with the first period Δtand the power flow P is suppressed in an inactive time window with the second period Δt. Via detection of an input current Iflowing at the input and/or an input voltage Uapplied to the input and comparison of values of the input current Iand/or input voltage Udetected in the inactive time window with a current threshold value Ior a voltage threshold value Uan arc presence criterion is signaled if the input current Idetected in the inactive time window falls below the current threshold value Iand/or the input voltage Udetected in the inactive time window does not exceed the voltage threshold value U. The application also describes a circuit arrangement for detecting an arc and a photovoltaic (PV) inverter including such a circuit arrangement.

Method and circuit arrangement for detecting an arc and photovoltaic (PV) inverter having a corresponding circuit arrangement

A method of detecting a serial arc fault in a DC-power circuit includes injecting an RF-signal with a narrow band-width into the DC-power circuit and measuring a response signal related to the injected RF-signal in the DC-power circuit. The method further includes determining a time derivative of the response signal, analyzing the time derivative, and signaling an occurrence of a serial arc fault in the power circuit based on the results of the analysis. A system for detecting an arc fault is configured to perform a method as described before.

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Huenfeld, Germany

Rainer Schmitt