Partial discharge diagnosis of stator insulation using damped AC voltages

In searching process for new, advanced technologies which could be applied for on-site diagnostics of machine insulation this paper discuses the application of damped AC voltages to detect and to analyze the PD processes. Based on laboratory investigation on a full scale stator insulation system, as well as during field inspections on large motors, a comparison of PD behavior: the PD inception conditions and PD levels at 50 Hz AC stresses and damped AC stresses has been performed. The applicability of PD detection at damped AC voltage has been discussed