Partial Discharge Failure in Medium Voltage Motors

Partial discharge (PD) measurements have long been used to assess the condition of the electrical insulation in motors and generators rated 3.3 kV and above. There are many ways to measure PD during the normal service of the motor or generator. The drawback with many methods of measuring PD in the stator windings is that measurements are influenced by electrical interference signals from poor electrical connections, tracking from insulators, discharges from connected terminations and other types of defects. The result can lead to false positives of stator winding problems, reducing the confidence in PD analysis.