A theoretical approach to the specific partial discharges-phenomenon in porous and multilayer composite structures

Partial discharges occurrence hi a porous and/or composite structure is a c omplex phenomenon. influenced by the specific interfacial polarisation, esp ecially at low frequencies, np to I-I) kHz. When the frequency of the applied voltage is increased, the partial dischar ge phenomenon is simultaneously influenced by the dynamics of the electric charge (under the unhomogenous electric field) and decrease of the permitti vity factor of the composite structure. Decreasing of the inception voltage versus high frequency could be evidence d; over 30 kHz, this phenomenon is more pronounced due to tilt: secondary t hermal effects. A complex analysis of the PD phenomena versus frequency (es pecially at low values of frequency, up to 10 kHz) call be used as an indir ect qualitative method in characterising the structure or technology of com plex dielectrics.