Space charge distribution measurement in complex insulating structures

Electrical insulation involves more and more complex structures in which the electrical field or the material can be heterogeneous. For testing space charge buildup in such structures, one-dimensional measurements are still often used owing to their simplicity. The sample complexity may however induce spurious effects that can be confused with space charge. In this paper, from the underlying physics of the pressure-wave-propagation (PWP) and the electro-acoustic (PEA) methods, limitations of the one-dimensional model are shown.