Polarization-depolarization measurements at insulation systems for rotating machines

For the condition evaluation of the electric insulation systems, dielectric measurements are a very important tool for the diagnosis. Beside partial discharge and dissipation factor measurements the dielectric response of the electrical insulation system gives further information about the aging process and the condition of the insulation medium. The measurement and analysis of the polarization and depolarization current (PDC) is done according to the classical equivalent circuit of parallel and serial resistances and capacitances. This paper should give a view to PDC measurements at insulation systems for rotating machines.