Synchronous 3-Phase Partial Discharge Detection on Rotating Machines

More and more the predictive maintenance of high power equipment is employed to contribute to its sustainable and economic operation. Partial discharge (PD) measurements are for this increasingly used for on-line and off-line condition assessment of rotating machines in the power generation, industrial drive application and traction. However, the main difficulties with the interpretation of PD measurement results are coupling with the electrical interferences that are inevitably present, and recognition and separation of different parallel active PD sources within the stator winding insulation. The usage of a new digital multi-terminal PD measurement system combined with new evaluation technique enables the noise recognition as well as the separation and further investigation of superimposed PD signals from different active sources. This makes the interpretation of partial discharge measurements on rotating machines much more significant and reliable. This paper describes the synchronous PD measurement system, evaluation technique and subsequently the abilities of the new PD measurement method exemplary by one on-line synchronous 3-phase measurement on a high voltage machine.