Differential protection device allowing the detection of leakage or fault currents in an electrical installation that is supplied with power either by at least two phase conductors of a network or by at least one phase conductor of a network and by a neutral conductor (N) of said network, said device comprising at least one detection and control module that is functionally active or operational for frequencies of the fault signal from 0 Hz to a few tens of Hz, this module being supplied with power by the network, this module comprising, on the one hand, a measurement torus made of a ferromagnetic material that the aforementioned conductors (2, 2', 2'', N) pass through, on the other hand, an excitation circuit for exciting the torus comprising a generator of AC signals that produces a periodic carrier (SPE) and, finally, a measurement winding that is able and intended to generate a fault signal (SD) resulting from the appearance of a differential fault in the network, said measurement winding being connected to circuits for processing and evaluating the fault signal (SD) and for transmitting a control signal (SC) to a breaking or opening means also forming part of the differential protection device , the aforementioned circuits (7 to 10) forming the components of an operational electronic chain belonging to the detection and control module , which device is characterized in that the circuits (7 to 10) of said operational chain comprise at least, on the one hand, a circuit that delivers a signal (SVMR) corresponding to the rectified average value of the fault signal (SD), or a derived signal (SD') that is directly dependent on said fault signal, and, on the other hand, a comparator circuit that compares said rectified average signal (SVMR) with a predetermined or preset threshold value and that conditionally or selectively delivers a control signal (SC) for controlling the breaking or opening means , depending on the result of said comparison. said device comprising at least one detection and control module that is functionally active or operational for frequencies of the fault signal from 0 Hz to a few tens of Hz, this module being supplied with power by the network, this module comprising, on the one hand, a measurement torus made of a ferromagnetic material that the aforementioned conductors (2, 2', 2'', N) pass through, on the other hand, an excitation circuit for exciting the torus comprising a generator of AC signals that produces a periodic carrier (SPE) and, finally, a measurement winding that is able and intended to generate a fault signal (SD) resulting from the appearance of a differential fault in the network, said measurement winding being connected to circuits for processing and evaluating the fault signal (SD) and for transmitting a control signal (SC) to a breaking or opening means also forming part of the differential protection device , the aforementioned circuits (7 to 10) forming the components of an operational electronic chain belonging to the detection and control module , which device is characterized in that the circuits (7 to 10) of said operational chain comprise at least, on the one hand, a circuit that delivers a signal (SVMR) corresponding to the rectified average value of the fault signal (SD), or a derived signal (SD') that is directly dependent on said fault signal, and, on the other hand, a comparator circuit that compares said rectified average signal (SVMR) with a predetermined or preset threshold value and that conditionally or selectively delivers a control signal (SC) for controlling the breaking or opening means , depending on the result of said comparison. <EOS>