A deconvolution technique for space charge recovery in lossy and dispersive dielectrics using PEA method

The Pulsed Electro-Acoustic method (PEA) is widely used both in laboratory for fundamental research and in industry for components assessment and diagnosis. However, in most cases, the technique is used without paying enough attention for acoustic losses and dispersive effects, which render the interpretation of the material/product response somewhat uncertain, especially when dealing with relatively thick samples. Moreover, for cable systems, PEA signals are affected by the acoustic wave propagation in the material and the response of the measurement system. We developed a deconvolution technique that takes into account the divergent effects due to coaxial geometry and insulation thickness. The accuracy of the recovered charge profile depends on the system modeling (especially the estimate of the attenuation and dispersion coefficients). Furthermore, simulation results show that the recovered charge profiles can be affected, to some extent, by the Signal to Noise Ratio of experimental data. A comparison between experimental results on power cables with and without the deconvolution technique is reported and discussed.