Dielectric phenomena in semicrystalline polymers

For the application of polymers in insulation systems it is essential to understand the dielectric phenomena leading to distinct electrical properties such as conductivity, permittivity, or electrical strength. It is generally accepted that space-charge formation plays an important role in these complex interactions, causing distortion of the electric field determined by the electrode configuration. An assessment of the electrical behavior of partially crystalline polymers requires the knowledge of the DC and AC properties and the interrelations with space-charge processes as well as the dependencies of the electric properties from structural conditions and their relaxations. Sophisticated experimental techniques such as polarization and depolarization current measurements, on-line measurement of charge carrier motions in AC fields, and highly sensitive and time-resolved partial discharge inception measurements provide necessary data for the understanding of dielectric phenomena and permit first approaches in analytical and numerical modeling