Proposal of Calibration Method for Space Charge Distribution in Laminated Films Using PEA Measurement System

A calibration technique using a newly developed electrode attachment was introduced to measure space charge distribution in laminated different materials using PEA method under a high dc stress. In many cases of insulating systems, different kinds of insulating layers are used by laminating with other materials. When a DC high voltage is applied to such layers, charges usually accumulate at the interfaces between the layer and the electrode and/or in the layers. While this phenomenon was already analyzed theoretically, actual charge accumulation seems to be different from the result derived from the theoretical analysis. To understand the phenomenon, the space charge distribution has been attempted to measure in a laminated sample. To measure it correctly, a calibration method that takes into account the sound velocity and the permittivity of both the double layered sample is required. Therefore, at first, we need to get a reference signal for calibrating the correct charge distribution. In this research, we developed a measuring attachment that applied a voltage to only one of the laminated two insulating material samples to acquire the signal necessary for calibration of the double layer sample. From the results, the reference waveform of a grounded electrode side sample was calculated using the obtained reference waveform in the laminated sample, and the reference waveform of a high voltage side sample can be obtained by calculating the shared voltage applied to each sample.