The trends of partial discharge extinction voltage (PDEV), partial discharge inception voltage (PDIV) and repetitive partial discharge inception voltage (RPDIV) as a function of duty cycle, frequency, and rise time are experimentally investigated in this paper. The presented study is performed on a Glass fibre insulated wire (i.e., Type-II insulation), when it is excited/stressed with both positive and negative unipolar voltage impulses. The collected data are post-processed through a two-parameter Weibull distribution (i.e., shape/slope), while considerations are drawn and in-depth discussed. In particular, the focus is given to the differences between PDIV and PDEV values, RPDIV and PDIV values, as well as the dispersion level of the measurements. In addition, the voltage overshoot resulting from fast rise time plays the main role in determining the over-voltages with respect to PDIV and PD activity. Thus, the trend of this waveform characteristic as a function of rise time will also be discussed in the paper.