Deconvolution techniques for space charge recovery using pulsed electroacoustic method in coaxial geometry

The Pulsed Electro-Acoustic method (PEA) is a powerful tool for assessing space charge accumulation in a large variety of polymeric materials having various thicknesses. However, the acoustic attenuation and dispersion phenomena, especially when dealing with relatively thick samples, affect the space charge resolution at positions far away from the sensor. Moreover, for cable systems, the PEA signals are affected by the electrostrictive effect, due to the divergent nature of the electric stress, which introduces extra-distortion on the PEA signal. In this work, we report on two different deconvolution techniques being temporal and frequential. Both methods correct, with a similar figure of merit, the wave attenuation, dispersion and electrostrictive effects. Application of such deconvolution algorithms on experimental signals from a model power cables enables to show injection of negative charges at the inner electrode which results in a built-up of negative heterocharges adjacent to the outer electrode during volt-on.