Ac resistance of the wire is a necessary for computational load flow parameters. Ac resistance is under the condition of the alternating current direction, due to the effect of the magnetic field, the influence of skin effect, and proximity effect, make resistance increases.
Ac resistance of aluminum wire with insulation of alumina membrane surface, so the current in the conductor is along the direction of aluminum wire spiral of fluid, thus formed in the conductor axis direction magnetic field.
Even though the wire adjacent layers of aluminum wire stranding in the opposite direction, can offset part of the magnetizing force, but the rest of the alternating magnetic field intensity, still can make the steel core produces hysteresis and eddy current, lead to power loss. And because skin effect and proximity effect can make the current in the conductor distribution change, make wire resistance increases.