A method specially designed for detecting events associated with partial discharges (PDs) in high voltage cables includes the identification of the location and the evaluation of the amplitude and rate of repetition per period of the grid voltage, with the possibility of identifying different sources producing PD signals as a function of the location thereof and recognising the type of defect associated with PDs in the same location. Generated electric signals are measured and the discriminated in relation to the background noise. A system for carrying out the method includes devices for discriminating the noise in relation to the transient waveform of the PD, determining the parameters associated therewith, determining the map of sources of PDs along the length of the cable, graphically representing the sources, and identifying the patterns of the sources of PDs separated as a function of the location thereof along the length of the cable.