Partial Discharge measurements in Electrical Machines controlled by Variable Speed Drives: from Design Validation to permanent PD Monitoring

The new IEC 60034-18-41 Standard deals with Partial Discharge (PD) measurements on random wound electrical rotating machines controlled by Variable Speed Drives (VSD). It settles down guidelines for PD measurements during both off-line and on-line conditions. The research work described in the current paper applies IEC standard requirements regarding the measurement setup, showing working cases where this approach was successful. The main purpose was not only to check for the presence of PD phenomena during design validation under specified stress conditions, but also to detect and monitor PD behavior versus time during service conditions.