Partial Discharge cross-talk recognition in rotating machines by pulse-shape analysis: preliminary results

During online partial discharge (PD) measurements on AC rotating machines, one of the noise typologies that affects PD patterns is the so called "cross-talk", that is, discharges that appear in the tested phase as a result of coupling from another phase. An approach to cross-talk recognition, based on PD-pulse shape and phase analysis, is presented in this paper. It is shown that, the signal distortion, due to the different propagation path, can help in separation of PD signals relevant to the main and cross-talk PD patterns. The cross-talk recognition can be achieved applying appropriate phase shift analysis to the separated PD patterns. The rejection of cross-talk patterns can make easier PD source identification and the relevant diagnostic decision can be more reliable.