FEM Based Preliminary Design Optimization in Case of Large Power Transformers

Pavel Karban,David Pánek,Tamás Orosz

doi:10.3390/app10041361

Abstract

Since large power transformers are custom-made, and their design process is a labor-intensive task, their design process is split into different parts. In tendering, the price calculation is based on the preliminary design of the transformer. Due to the complexity of this task, it belongs to the most general branch of discrete, non-linear mathematical optimization problems. Most of the published algorithms are using a copper filling factor based winding model to calculate the main dimensions of the transformer during this first, preliminary design step. Therefore, these cost optimization methods are not considering the detailed winding layout and the conductor dimensions. However, the knowledge of the exact conductor dimensions is essential to calculate the thermal behaviour of the windings and make a more accurate stray loss calculation. The paper presents a novel, evolutionary algorithm-based transformer optimization method which can determine the optimal conductor shape for the windings during this examined preliminary design stage. The accuracy of the presented FEM method was tested on an existing transformer design. Then the results of the proposed optimization method have been compared with a validated transformer design optimization algorithm.

Highlights

Large power transformers are generally specific, tailored to the unique customer requirements
The metaheuristic method uses the combination of the method of branch and bound and geometric programming to find the optimal solution of an analytical transformer model
It was shown in a previous article [27], that the usage of this geometric programming based solver guarantees that this method finds the global optima of the optimization task [14,27]

Summary

Introduction

Large power transformers are generally specific, tailored to the unique customer requirements. In case of large machines their design process is a complex, labour intensive task, where many physical fields have to be considered simultaneously [1,2,3]. A preliminary design is made to determine the final price and the key-design parameters of the cost optimal transformer design (Figure 1). The uniqueness is a very important factor during the design and optimization of very large machines. Only one design is built with the given requirements, there is no other possibility to tune or refine the parameters after the measurements. The manufacturing cost of these machines are very high, a company can win (or loose) a lot of money if it can won the bidding procedure with a good preliminary design. The mathematical representation of this problem belongs to the most general branch of discrete, non-linear mathematical optimization problems [9]

Methods

Results

Discussion

Conclusion