Diagnosis of practical insulation systems by partial discharge measurements in the presence of multi-discharge phenomena

The shape analysis of multiple partial-discharge (PD) phenomena is addressed in connection with the representation of the cumulative PD height distribution in a Weibull plot. It is shown that a multiplicatively-Weibull distribution can fit PD data obtained from measurements performed on stator bars when two PD phenomena are superimposed. Pattern identification and clustering is thus achieved, so that each PD phenomenon can be investigated as a function of measurement voltage and aging time. The effectiveness of the Weibull representation as a diagnostic tool is therefore derived.<<ETX>>