Examination of anisotropic material characteristics in Outer Corona Protection (OCP) systems in large rotating machines

Abstract

In large rotating machines the insulation system is extended by a field grading systems to provide an optimal electrical field distribution in the main insulation. In this study the anisotropic electrical material properties of the Outer Corona Protection (OCP) field grading system are analyzed. By modeling real OCP test samples and subsequent numeric calculation the systems field properties are characterized. Due to the consideration of complex spatial substructures, like the overlapping tape layers in the examined field grading system, the local field distributions will lead to an optimization of OCP resistivity configurations.