Method for detecting arcs in photovoltaic systems and such a photovoltaic system

A method for detecting arcs in a direct-current path of a photovoltaic system, comprising the following steps:

• detecting values of a current (IDC) of the direct-current path during a repeating time frame;
• generating a mean value of the current (IDC);
• detecting values of a voltage (UDC) of the direct-current path during the time frame (t);
• generating a mean value of the voltage (UDC);
• and
• continuously calculating at least one detection signal and at least one detection threshold based on the mean value of the current and mean value of the voltage by means of a calculation method,
• wherein the detection signal and the detection threshold are calculated by means of calculating a difference mean value, a long-term mean value and a long-term difference mean value of each of the current and the voltage by digital low-pass filtering, and
• wherein a value is generated from the long-term difference mean value and the difference mean value of the voltage, and multiplied by a value generated from the long-term difference mean value and the difference mean value of the current to generate the detection signal.