An electronic protection device for a LV electric line including one or more conductors (P, N), comprising: - one or more pairs of electric contacts electrically connectable with corresponding conductors of said electric line and mutually coupleable or decoupleable; - a control unit adapted to control the operation of said electronic protection device and comprising a controller , wherein said control unit comprises a first detection module adapted to detect a line current (IL) flowing along said electric line and provides a first detection signal (DS1) indicative of the behaviour of low-frequency components of said line current; wherein said control unit comprises: - a second detection module adapted to detect a line current (IL) flowing along said electric line and provide a second detection signal (DS2) indicative of the behaviour of high-frequency components of said line current; - a comparison module adapted to process said second detection signal (DS2) and provide a logic signal (LS), the behaviour of said logic signal depending on the behaviour of said second detection signal; - a third detection module adapted to process said logic signal (LS) and provide a third detection signal (DS3) indicative of the presence of level transitions in said logic signal, - a determination module adapted to process said first and third detection signals (DS 1, DS3) and determine the presence of arc fault conditions in said electric line, said determination module providing a trip signal (TS) if arc fault conditions are determined; characterised in that said third detection signal (DS3) is formed by a sequence of count values (N1), wherein two subsequent count values are separated by a constant time interval (Ts) corresponding to a sampling period adopted by said controller, each count value being indicative of a number of level transitions of said logic signal (LS) occurring within a corresponding time interval (Ts). - one or more pairs of electric contacts electrically connectable with corresponding conductors of said electric line and mutually coupleable or decoupleable; - a control unit adapted to control the operation of said electronic protection device and comprising a controller , wherein said control unit comprises a first detection module adapted to detect a line current (IL) flowing along said electric line and provides a first detection signal (DS1) indicative of the behaviour of low-frequency components of said line current; - a second detection module adapted to detect a line current (IL) flowing along said electric line and provide a second detection signal (DS2) indicative of the behaviour of high-frequency components of said line current; - a comparison module adapted to process said second detection signal (DS2) and provide a logic signal (LS), the behaviour of said logic signal depending on the behaviour of said second detection signal; - a third detection module adapted to process said logic signal (LS) and provide a third detection signal (DS3) indicative of the presence of level transitions in said logic signal, - a determination module adapted to process said first and third detection signals (DS 1, DS3) and determine the presence of arc fault conditions in said electric line, said determination module providing a trip signal (TS) if arc fault conditions are determined; characterised in that said third detection signal (DS3) is formed by a sequence of count values (N1), wherein two subsequent count values are separated by a constant time interval (Ts) corresponding to a sampling period adopted by said controller, each count value being indicative of a number of level transitions of said logic signal (LS) occurring within a corresponding time interval (Ts). <EOS>