Symmetrical-Component Circuit Constants and Neutral Circulating Currents for Concentric-Neutral Underground Distribution Cables

Use of single-conductor concentric-neutral cables in underground distribution requires a method with new features for proper inclusion of the effects of the concentric- neutral upon the positive-and negative-sequence network impedances. Circulating currents in the concentric-neutrals cannot be ignored in any of the sequence networks, and the dissymmetry in cable spacing substantially increases the effects.