Partial discharge measurements to assess rotating machine insulation condition: a survey

The measurement of partial discharges has become the most popular means of assessing the degree of aging in solid electrical insulation systems. In particular, PD testing has become the principal means of assessing motor and generator stator winding condition. Many advances in measurement technology were required to achieve this state. For example, advances in sensors were needed to distinguish PD from noise signals on a pulse-by-pulse basis. Furthermore, improved digitizers as well as advanced graphical display methods have been useful in making it easy for nonexperts to distinguish between the different types of PD. In the future, statistical and neural network technology seems to hold the promise of enabling nonexperts to make better use of PD data.