Guven Komurgoz

This study presents a comprehensive comparison of transformer core size and no-load losses, focusing on transformers with power ratings ranging from 400 kVA to 3200 kVA. The research evaluates transformer performance at three distinct primary voltage levels: 6 kV, 15 kV, and 33 kV, while maintaining a constant secondary voltage of 0.4 kV. Additionally, the study investigates the impact of two commonly used transformer core materials, M4 and H0, on core design, with a particular focus on their effects on no-load losses. Another central aspect of the analysis is the examination of core geometry, including the cross-sectional area and height of the transformer core, across various power ratings and voltage levels. The results reveal a clear relationship between core size and energy efficiency. M4 cores exhibit higher no-load losses compared to H0 cores; additionally, H0 cores demonstrate better overall efficiency, making them ideal for high-efficiency applications. The findings underscore the importance of selecting the right core materials and geometries to balance performance, efficiency, and size. These insights are intended to guide researchers and transformer designers in making informed decisions when developing energy-efficient solutions for diverse applications across the electrical power industry.

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.

Shunt reactors are widely used for controlling the reactive power in the power network. During the design of the shunt reactor, iron losses and copper losses play a very important role. In this study, a highly-accurate numerical technique, the finite element method is used to calculate the losses at the nominal and rated power. The main aim of this study is to calculate the core losses and copper losses in the shunt reactor using the finite element method. Magnetic flux density distribution during the nominal and rated power is also examined using the finite element method. The experimental results of the losses during the nominal and rated power are also compared with the numerically calculated results.

In wind turbine applications, an accurate turbine model and effective control algorithms are needed to ensure power flow in accordance with grid standards and design criteria. However, ...

In this study, the multi-objective optimal design of functionally graded material flywheels is obtained using the non-dominated sorting genetic algorithm-II. The variations in temperature along the flywheel radius due to the operating conditions and environmental changes are taken into consideration in design optimization. Variations in the elastic and thermal properties of materials with temperature are taken into consideration for the first time, to the best of the authors’ knowledge. The thermoelastic equations of motion and the heat equation are derived and then solved by the generalized differential quadrature method. Results for temperature variation, radial displacement and von Mises stress are compared with the results of finite element analysis, and very good agreement is observed. Designs with optimal cross-sectional geometry and material distribution that give minimum mass and maximum kinetic energy are obtained.

The study presents power flow modelling for dynamic systems featuring chain structures. For this purpose, the Bond Graph method is particularly suitable. This tool describes engineering systems in different fields via domain-independent graphical representation using general dynamic modelling for any physical system. Even repetitive constructions called chains can be modelled. This paper aims for power flow based dynamical models of serial type chain structures. Further graphical systematization identifies four basic scalar segments which again correlate with four general vectorial total model structures. Examples and general algorithms, to obtain the scalar segment model and the vectorial overall model, support the proposed modeling. The main vectorial modelling element is identified as a relative coordinate transformation. The approach includes usage for open and closed chains plus rings of ring structures. It aims at universal usage independent of serial chain structure type, application domain or software tool. Moreover, it can be used beneficially in various non-physical fields.