A method and associated device for detecting arcs in a photovoltaic system with an inverter and with a plurality of current collector circuits connected in parallel with the inverter via collector lines, wherein a plurality of strings of photovoltaic modules are connected in parallel with each current collector circuit via string lines. The method includes acquiring measured values of electrical variables and analyzing the measured values of the electrical variables for the presence of signs of an arc in the photovoltaic system using an analysis circuit and generating an arc signal which indicates the presence of an arc if the analyzed measured values meet predefined criteria. The method also includes acquiring measured values of acoustic variables using one or more acoustic sensors, and analyzing the measured values of the acoustic variables for the presence of signs of an arc in the photovoltaic system using the analysis circuit.