Effect of temperature gradient on space charge waveform in pulsed electroacoustic method

Temperature rise of power equipment in service seriously affect the lifetime of insulation, so many researchers have focused on space charge measurements at high temperature. But the changes of polymeric properties (e.g. sound impedance, Young's modulus, density, velocity of sound wave, decay characteristic etc.) at high temperature make measurement of space charge profiles in polymer inaccurate. What is more, the changes of polymeric properties are more complex under temperature gradient. In this paper, based on the propagation characteristic of sound wave in pulsed electroacoustic method and temperature dependence of polyethylene properties, the effect of temperature gradient on space charge measurement is analyzed and the space charge waveform is recovered.