Analysis of irregularity factor of stranded conductors

The paper presents a theoretical derivation of the irregularity factor of stranded conductors, the irregularity factor being defined as the ratio of maximum surface voltage gradient of a stranded conductor to that of a smooth conductor of the same overall diameter and of the same charge. The method is based on conformal mapping of circular-arc triangles. When applied to 7-, 19- and 37-strand conductors, the irregularity factors obtained were 1.407, 1.436 and 1.445, respectively. The field around the conductor is also completely known from the analysis.