Reversible hydroelectric device that can be installed on an outside pipe, comprising a hydraulic power unit comprising a hydraulic machine comprising a centrifugal pump that can be reversed as a turbine and a hydraulic circuit having bypass branches and motorized valves allowing circulation of water in said hydraulic machine in one direction or the other irrespective of the direction of circulation of the water in said outside pipe; an electric machine coupled to said hydraulic machine and comprising an asynchronous motor that can be reversed as an asynchronous generator; and an electronic system comprising a programmable controller for adjusting and/or regulating said valves and an electronic variator for adjusting and/or regulating the rotation speed of said electric machine so that the pressure and/or flow rate downstream of the hydraulic machine depending on the direction of circulation is/are stabilized or adjusted to at least one set point value.