A new method for space charge measurements in dielectric films for power capacitors

Space charge measurements form a recognized test for the characterization of insulating materials. The present paper is concerned with the determination of space charge in dielectric films for capacitors. We develop a new measuring technique inspired by thermal step method (TSM). Its originality is the use of an alternative thermal excitation so that the technique can be called alternative thermal wave method (ATWM). The equipment employed to generate alternative thermal excitations (sine or triangle) is described. The upper limit of the efficient frequency range is 10 Hz. Signal processing is made easier and more accurate because of the periodicity of the measured phenomena.