A system and method for measuring a perpendicular wind speed component with respect to a suspended cable span. The method includes monitoring a motion of at least one point of the suspended cable span over a time interval, and determining whether the motion includes Aeolian vibration. If the motion does not include Aeolian vibration, a transverse swing angle of the suspended cable span is measured and the perpendicular wind speed component is calculated as a function of the transverse swing angle. If the motion includes Aeolian vibration, a frequency of the Aeolian vibration is measured and said perpendicular wind speed component is calculated as a function of the Aeolian vibration frequency. The method may include measuring an effective incident radiation and for determining a maximum allowable current rating, or “ampacity”, for the suspended cable span, as well as for supplying electric power over a power line comprising said power span.