Experimental considerations on the possible impact of space charge accumulation on partial discharges activity for wire insulations

The impact of space charge accumulation caused by unipolar square waveform excitation on partial discharge inception voltage (PDIV) and partial discharge extinction voltage (PDEV) for one Type-II insulated wire, i.e., Glass fibre and one Type-I insulated wire Polyether Ether Ketone (PEEK), are compared and investigated experimentally in this paper. Two rise times (i.e., 80 and 800 ns) and two impulse voltage repetition frequencies (i.e., 50 Hz and 2.5 kHz) are considered under different exposure times. Additionally, the influence of rise time and impulse voltage frequency on PDIV level of dispersion as a function of exposure time is compared for the two insulated wires, relying on the shape/slope parameter of the Weibull distribution.