The influence of high frequencies and high dV/dt on the partial discharge inception voltage (PDIV) and the lifetime under partial discharge stress of PET films (23-75 µm) are investigated. The tests are carried out using a sphere–plate electrode arrangement with spheres of different diameters (3-7 mm). The films are stressed at high frequencies (10-400 kHz) using bipolar rectangular voltages generated by a SiC full bridge, with voltage slopes of 25 V/ns and 44 V/ns. Partial discharges are detected using a high-frequency current transformer and a high-pass filter with a cutoff frequency of 120 MHz.
