Dielectric response analysis as tool to assess the mechanical deterioration of VPI insulation

In this paper test bars are mechanically aged by means of a cyclic bending test setup. At specific time intervals the dielectric response analysis is performed on these bars. This diagnostic technique consists of a combination of polarization and depolarization current (PDC) measurement in the time-domain and frequency-domain processing of the measurement results together with a frequency-domain spectroscopy (FDS). The aim of this work is to investigate the possibility to assess the degree of mechanical deterioration by means of this diagnostic technique. Ideally, a correlation between the mechanical lifetime consumption and the change in the measurement results can be derived.