Device for supplying electrical energy from a plurality of strings of photovoltaic modules to a power grid

In a device (1) for supplying electrical energy from a plurality of strings (2) of photovoltaic modules (3) to a power grid (4), which comprises a connection terminal (7) for each string (2) of the plurality of strings (2), each connection terminal (7) comprising over-current protection means including a power switch (9) for selectively disconnecting the respective string (2), and a central insulation monitoring unit (15) providing an insulation status of the entire plurality of strings (2); ; the power switch (9) of each over-current protection means is an all-pole disconnecting power switch (9) which can be opened and closed by a controller (11 -13) via a motor in response to the insulation status provided by the central insulation monitoring unit (15) to select and selectively disconnect a string having an insulation failure, and to further supply electrical energy from the remaining strings (2) of the plurality of strings (2) having no insulation failure.