Abstract: The present invention refers to a device for dynamically neutralizing vibrations in single cable overhead power transmission lines. The device comprises a main body (2) a screw (5) and washer (6) assembly for mounting the main body onto the cable (3) and inertial components (11) consisting of rods (13) projecting in opposite directions from said main body (2) and balance masses (14) positioned at the distal end of said rods, wherein said main body (2) is integrally manufactured and comprises an upper frontal portion to receive an embracing lid (4) that embraces the cable (3) and side portions for mounting matching viscous-elastic components (7).