Space charge and conduction current measurement using improved pulse generator

In this study, the PEA method that measures the space charge distribution over time in the polymer insulation material with high voltage applied was modified. While most of the existing measurement method measures the space charge distribution only, the improved PEA method can measure both space charge distribution and conduction current simultaneously. When space charge distribution and conduction current are measured respectively, some subtle changes on the electrode-insulator interface might affect the conduction characteristics. That problem can be avoided with the improved PEA method. Meanwhile, the relationship between space charge and electrical conductivity, as well as the affection on the electrical conductivity and insulation characteristics due to the existing space charge, could be analyzed directly. To generate pulse with more desirable waveform, shorter pulse width and higher frequency for the space charge distribution measurement, the mercury switch was replaced by a semiconductor switch in the pulse generator. As a result, the improved method is with higher resolution and shorter measurement cycle, which may make some effort for the investigation on the relationship between space charge and conduction current.