Monitoring system of wind-induced motion or vibration in at least one overhead cable, in particular a conductor aerial cable of a transmission or distribution electric line, said monitoring system comprising: at least three sensor nodes adapted to be installed in positions different from each other on a first overhead cable and configured for detecting said motion or vibration through a synchronous signal acquisition; each of said at least three sensor nodes comprising: - a respective triaxial accelerometer sensor configured for acquiring a first node signal; - a first processor configured for identifying, in said first node signal, a maximum node amplitude and an associated node frequency through a spectral analysis of said first node signal; said monitoring system further comprising a processing unit operatively associated with said at least three sensor nodes and comprising: - a second processor configured for comparing to each other at least three maximum node amplitudes of said at least three sensor nodes, respectively, for identifying a selected maximum amplitude and an associated selected frequency, said selected maximum amplitude being the maximum of said at least three maximum node amplitudes; wherein said respective triaxial accelerometer sensor in each of said at least three sensor nodes is further configured for acquiring a second node signal; wherein said first processor is further configured for identifying in said second node signal, a node selected amplitude and an associated node selected phase through a spectral analysis of said second node signal, said node selected amplitude and said node selected phase being associated with said selected frequency; and wherein said second processor is further configured for calculating a numerical model based on at least three node selected amplitudes and associated at least three node selected phases, for all of said at least three sensor nodes, for reconstructing said motion or vibration in any point of said at least one overhead cable according to said selected frequency. at least three sensor nodes adapted to be installed in positions different from each other on a first overhead cable and configured for detecting said motion or vibration through a synchronous signal acquisition; each of said at least three sensor nodes comprising: - a respective triaxial accelerometer sensor configured for acquiring a first node signal; - a first processor configured for identifying, in said first node signal, a maximum node amplitude and an associated node frequency through a spectral analysis of said first node signal; - a respective triaxial accelerometer sensor configured for acquiring a first node signal; - a first processor configured for identifying, in said first node signal, a maximum node amplitude and an associated node frequency through a spectral analysis of said first node signal; said monitoring system further comprising a processing unit operatively associated with said at least three sensor nodes and comprising: - a second processor configured for comparing to each other at least three maximum node amplitudes of said at least three sensor nodes, respectively, for identifying a selected maximum amplitude and an associated selected frequency, said selected maximum amplitude being the maximum of said at least three maximum node amplitudes; - a second processor configured for comparing to each other at least three maximum node amplitudes of said at least three sensor nodes, respectively, for identifying a selected maximum amplitude and an associated selected frequency, said selected maximum amplitude being the maximum of said at least three maximum node amplitudes; wherein said respective triaxial accelerometer sensor in each of said at least three sensor nodes is further configured for acquiring a second node signal; wherein said first processor is further configured for identifying in said second node signal, a node selected amplitude and an associated node selected phase through a spectral analysis of said second node signal, said node selected amplitude and said node selected phase being associated with said selected frequency; and wherein said second processor is further configured for calculating a numerical model based on at least three node selected amplitudes and associated at least three node selected phases, for all of said at least three sensor nodes, for reconstructing said motion or vibration in any point of said at least one overhead cable according to said selected frequency.