Comparative design and economic analysis of dry-type power transformers: Comparative study of copper and aluminum windings

This paper explores the effect of winding material selection on the design and performance of dry-type distribution transformers with power ratings from 400 kVA to 3,000 kVA. Each transformer is manufactured with specific limits for electromagnetic and heat conditions: Leakage impedance kept at 6% with a ±10% allowance, a magnetic flux density of 1.7 T, and winding temperature rise kept under 100 K, in accordance with IEC 60076-11 guidelines. The number of turns, core dimensions, conductor cross-sectional area, and the space between windings were adjusted to satisfy these conditions across varying power levels. The study is structured in two stages. First, losses, cost, and weight are individually evaluated for both materials (copper and aluminum) across different power ratings. Second, a comparison between copper and aluminum windings is performed to highlight trade-offs in efficiency, material usage, and design impact. Experimental results reveal that although copper offers improved conductivity and compactness, aluminum remains a viable alternative, especially where cost and weight are priority concerns. The outcomes provide practical insights for transformer designers aiming to optimize material usage in medium-voltage dry-type applications. These findings contribute to the development of energy-efficient and sustainable transformer designs, which are critical for the advancement of clean energy systems. Implementing optimized material selection can support reduced environmental impact and promote sustainable power distribution solutions in modern electrical networks.