Optimization of Distribution Transformer Design for Harmonic Resilience using a Taguchi-FEM Approach

Abstract

The Nigeria's low-voltage distribution transformers suffer from significant harmonic issues leading to catastrophic failures. Existing strategies to address harmonics have overlooked transformer inherent parameter design optimizations. This study presents the optimization of a 30 kVA transformer, focusing on enhancing efficiency and minimizing harmonic susceptibility for low-voltage distribution systems in Nigeria. Utilizing a combined Taguchi-FEM approach, result shows that key design parameters were optimized with core area (0.773 m²), material (Amorphous Steel), core design (Six-Stepped Core), and flux density (1.354T), resulting in a 27% reduction in energy losses. Finite Element Analysis (FEA) revealed that the optimized transformer exhibited a core saturation of 19.2%, significantly lower than the baseline's 42%, and demonstrated reduced energy density near the core-winding interface. Experimental validation through Open Circuit (OC) and Short Circuit (SC) tests confirmed a notable improvement in efficiency, with the optimized transformer achieving 97.15% efficiency at full load, compared to 95.5% for the baseline transformer. Core losses were reduced to 85W, and copper losses decreased to 800W. Also, the findings revealed a significant reduction in Total Harmonic Distortion (THD) from 16.78% in the baseline design to 4.12% in the optimized configuration. The findings align with international standards (IEC 60076-8). Optimizing core materials and stepped core design with advanced modeling can enhance reliability and reduce harmonic impacts. This study’s outcomes have potential promise on stable transformer operation, harmonic mitigation and reduced losses, enhanced reliability, and overall power systems stability; as well as the potential promise in terms of overall power systems cost savings and energy efficiency. Therefore, integrated optimization approaches, incorporating Taguchi-FEM and experimental techniques, can effectively enhance transformer performance, paving the way for broader applications in the field.