False alarm resulted from mixed data collected on Pdm

PD can come from multiple sources; from inside the transformers, through the power line, through the neutral line, and even through the air. It has also been noted that false alarms frequently occurred due to the detection of false data of Pdm. Thus the creditability of Pdm's performance is in question.

These case studies are the results of investigation on the PD sources detected from the transformer tests. The test confirms how the false alarms can happen from collecting PD from the transformer that generated from the outside (PD signal traveling through the HV power line).