Analytical solution of the mutual inductance of a HV single conductor cable with corrugated metallic sheath

In this paper, the analytical solution of the mutual inductance between the centre conductor and the sheath of HV single conductor cable with corrugated metallic sheath is deduced based on the Maxwell equations. The parametric equation of the helical and annular corrugated sheath cable is proposed as the limits of surface integral of the magnetic flux within the sheath. The mutual inductances of 110kV cables with 400mm2, 800mm2, 1 200mm2 cross-section are analyzed. The results show that the mutual inductance increases with the increase of the sheath thickness and embossing depth, and decreases with the increase of the geometric mean distance between conductor and sheath. The analytical solution is consistent with the numerical solution. Besides, the approximate solution of mutual inductance calculated by the geometric mean distance is 0.2~0.3% smaller than that of the analytical solution. For a long cable with multiple pitches, the mutual inductance of HV cable with helical and annular corrugated sheath is identical, whilst smaller than that with smooth sheath. © 2020, Electrical Technology Press Co. Ltd. All right reserved