Modelling the Temperature-Dependent AC Resistance of Two-Layer Steel-Core Conductors for DLR Applications
A. Soni(1,2), J.-R. Riba(2), M. Moreno-Eguilaz(2) 1. SICAME-Spain, Sant Esteve Sesrovires, Spain 2. Electrical Engineering Department, Universitat Politècnica de Catalunya, Terrassa, Spain. 2026-06-27

Abstract

Steel-cored conductors, and specifically aluminum conductors steel-reinforced (ACSR), are widely applied in overhead power lines. However, because of the magnetization of the steel core, such conductors exhibit a non-linear electrical behavior, and their electrical resistance depends on the intensity of the current flowing through the conductor. This paper analyzes the alternating current (AC) resistance of two-layer ACSR conductors. It compares different formulations to predict their AC resistance and concludes that the existing formulations fail in predicting the current dependency of the AC resistance in the lower current range. The results presented here show that the magnetic flux generated by the two aluminum layers is not completely cancelled out, although the two layers are stranded in opposite directions. It is also shown that this effect is more pronounced at low current levels.

Key words: Conductors, steel core, power lines, power loss, dynamic line rating, ampacity.

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