The study of PEA space charge waveform recovery under temperature gradient

As the temperature difference exists between the inner and outer conductors of high voltage DC cables in practice, it is important to study space charge behavior under temperature gradient. However, due to the effect of temperature on the acoustic propagation, it is necessary to study the waveform recovery method in pulsed electroacoustic (PEA) measurement. In our previous study, only the effects of temperature on acoustic velocity and attenuation were considered in the waveform recovery. As the density of material will not be continuously uniform under a temperature gradient, the dispersion of acoustic waves due to the change of acoustic resistance should be also taken into consideration. In this report, the characteristics of acoustic propagation under temperature gradient are discussed, and a new algorithm for waveform recovery is put forward, and the distortion of the waveform can be successfully suppressed.