Analysis on Uncertainties in Measurement of Space Charge Distribution in Dielectrics


 The results obtained by the commonly used space charge distribution measurement methods are frequently apparent and one-dimensional results of a localized area, and there may be random errors caused by various factors. In this work, three factors—sample thickness uniformity, pressure wave intensity uniformity, and space charge distribution uniformity—that may cause measurement uncertainties are examined. The analysis and evaluation of the experimental data are impacted by the measurement uncertainties, which are particularly noticeable in the experiments of semiconductive electrode-flat polyethylene (PE) samples using the laser-induced pressure propagation (LIPP) method. These factors are investigated separately with several auxiliary experiments, including laser beam spot energy distribution measurement and space charge distribution measurements at different measuring positions on the same uniform sample. A clear and intelligible model is developed to discuss the influence of these factors on the uncertainties in the space charge distribution measurement in dielectrics.