Power transformers illustrate the majority of capital investment in transmission and distribution centers. Additionally, interruptions of power transformer have a significant economic Effects on the Performance of an electrical network. For this reason, the safe and reliable Performance relate directly to the Security and stability of power system. This paper studies the growth of power losses and Derating of Distribution transformer, working under unbalance voltage and unbalanced load conditions. In this paper, computer-based simulation utilizing the two and three dimensional finite element methods (3-D and 2_D FEM) are exploited as a tool for visualizing magnetic fields of distribution transformers. Finite Element Method (FEM) is one among popular numerical methods that is able to handle problem complexity in various forms. The performance of the transformer when the load and supply are balanced compared to the case in which voltage or load is unbalanced indicates that the unbalanced load only causes the copper loss to increase, while the unbalanced voltage not only increases copper loss but also adds to the core loss. The indices of voltage unbalance factor (VUF) are used in this paper to evaluate the unbalance propagation. This process enables the software to simulate and analyze different electromagnetic parameters such as magnetic flux lines, flux density, losses, and etc, under different input sources with high accuracy.

A transformerless, single-phase, buck–boost inverter is proposed in this study. Unlike similar topologies, the proposed inverter does not need to have a mid-point of dc sources or dc-bus capacitors at the input side of the inverter. The proposed inverter can suppress the leakage current drawn from the input power source and provide a long-lasting solution for applications with a wide input voltage range and/or unregulated input voltage. This article presents the controller and modulation design details, and a comparative evaluation conducted for the proposed inverter. A single-phase, buck–boost inverter for realizing the power stage with 110 V _rms output ac voltage and a range of 100–200 V input dc voltage is investigated in this study. The proposed inverter has been proven through theory, computer simulations, and experimental studies with SiC mosfet s-based prototype of a 300 VA power supply. Theory, computer simulation, and experimental results are all correlated.

The demand for electrical energy is increasing day by day with the development of technology in the world. Distributing electric energy to all regions that need energy is a principal issue, and this necessitates the use of transformers to convert the voltage to the desired level. Accordingly, the use of transformers, one of the electrical devices converting AC voltage level at a defined frequency has grown significantly. In this study, design parameters of a 25 kVA, 33/0.4 kV, Yzn11, oil-type distribution transformer are optimized using the Multi-Objective Genetic Algorithm (MOGA) technique by decreasing the weight of the significant materials and manufacturing cost. Electromagnetic analysis of the transformer is performed with ANSYS Maxwell based on the design results obtained from the optimization study for validation of the method. The experimental design parameters are also compared with the optimization results. It is observed that optimum results are achieved by using the proposed approach.

Transformers are considered as the significant contributors to the efficient transmission and distribution of electrical energy. The ability to change the voltage and current levels in inverse proportion help to reduce the conductor losses. However, today’s stringent requirements for more significant efficiency markings turn attention to the efficiency of individual components in a power system. Therefore, a great deal of effort is being placed to maximize the efficiency of the transformers without compromising their fundamental function. This is a complex problem and requires the use of advanced design tools. Metaheuristic methods developed in recent years are being used in electrical engineering, where they provide savings in design time and great success in finding the optimum solution. In this study, we have used the Particle Swarm Optimization (PSO), the Simulated Annealing (SA), and the Tree Seed Algorithm (TSA) methods, respectively. The objective is to develop a design methodology for three-phase dry-type transformers and to maximize their efficiency. The results of the three algorithms are compared to validate the optimum solution. For the demonstration of the process, a three-phase 100 kVA dry-type transformer is used. After the mathematical model of the transformer is created, the transformer parameters, current density (s), and transformer iron cross-section acceptability (C) are optimized. As a result, it has been observed that the efficiency of transformers can be increased beyond what is achieved with conventional techniques. The efficiency has been optimized and increased from 97.5% to 98.44%.

The integration of compact concepts and advances in permanent-magnet technology improve the safety, usability, endurance, and simplicity of unmanned aerial vehicles (UAVs) while also providing long-term operation without maintenance and larger air gap use. These developments have revealed the demand for the use of magnetic couplers to magnetically isolate aircraft engines and starter-generator shafts, allowing contactless torque transmission. This paper explores the design aspects of an active cylindrical-type magnetic coupler based on finite element analyses to achieve an optimum model for hybrid UAVs using a piston engine. The novel model is parameterised in Ansys Maxwell for optimetric solutions, including magnetostatics and transients. The criteria of material selection, coupler types, and topologies are discussed. The Torque-Speed bench is set up for dynamic and static tests. The highest torque density is obtained in the 10-pole configuration with an embrace of 0.98. In addition, the loss of synchronisation caused by the piston engine shaft locking and misalignment in the case of bearing problems is also examined. The magnetic coupler efficiency is above 94% at the maximum speed. The error margin of the numerical simulations is 8% for the Maxwell 2D and 4.5% for 3D. Correction coefficients of 1.2 for the Maxwell 2D and 1.1 for 3D are proposed.

In this study, losses analysis at bushing regions of a transformer covers is done using finite difference method (FDM), considering that FDM being more flexible to deal with the nonlinear constitutive law and easier to be implemented than finite element (FE) and analytical methods. The analysis is performed based on a 2-level adaptive mesh solution of Maxwell equations and Ohm law at the cross section area in the axial symmetry page of a steel disk, taking account the nonlinear magnetic permeability of the steel. The losses density obtained, as a heat source, is imported into an alternating direction implicit (ADI) approach of heat conduction equation. Therefore, a finite difference (FD) solution algorithm for magneto-thermal analysis on cover plate is obtained by combination of adaptive mesh refinement and ADI-FDM, which improves the accuracy and decreases the computational time without losing accuracy. The reliability of the proposed technique is confirmed by experimental and FE method (FEM) results, considering the temperature distribution of the cover. The comparison of the results with those obtained from FEM and experiments shows the efficiency and capability of the method.