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Shape Optimization of Coils and Cooling Ducts in Dry-Type Transformers Using Computational Fluid Dynamics and Genetic Algorithm | IEEE Journals & Magazine | IEEE Xplore

Shape Optimization of Coils and Cooling Ducts in Dry-Type Transformers Using Computational Fluid Dynamics and Genetic Algorithm


Abstract:

In this paper, shapes of cooling ducts in dry-type transformers are optimized using computational fluid dynamics (CFD) and the Genetic Algorithm (GA). The GA is used to o...Show More

Abstract:

In this paper, shapes of cooling ducts in dry-type transformers are optimized using computational fluid dynamics (CFD) and the Genetic Algorithm (GA). The GA is used to optimize diameters of both ducts and coils. Constraints in the optimization process are the minimum distance between the high-voltage (HV) and the low-voltage (LV) windings and the outer diameter of coils. Since the investigated transformer is a special unit, two objective functions (OF) were applied to minimize the average and the maximum temperature of the windings, and thus the coil power losses. The OF value is determined using a CFD model that accounts for all three heat transfer modes. The local total heat fluxes are specified on the model external boundaries. The thermal properties of the coils and core are treated as anisotropic and temperature-dependent quantities, while the power losses are treated as heat sources and are computed based on the coupled CFD-EMAG model. Both coil properties and losses vary with each generated coil configuration. The results show that the nonuniform positioning of the wires and air ducts can significantly improve the heat dissipation. Consequently, the coil losses are substantially reduced.
Published in: IEEE Transactions on Magnetics ( Volume: 47, Issue: 6, June 2011)
Page(s): 1726 - 1731
Date of Publication: 31 January 2011

ISSN Information:


I. Introduction

Electrical transformer reliability and lifespan strongly depend on cooling conditions. In a typical case, the windings and core are cooled either in transformer oil or, using a fan, by the air circulating inside the tank. However, there are also environments in which natural air cooling is the only option. For example, in underground coal mines, ANAN devices (natural air cooling both inside and outside a tank) are placed in hermetic tanks. For such special units, the desired electrical device parameters are more important than a cost reduction policy. Furthermore, the tank space is often limited because of a small size of underground corridors. In addition, electricity demand constantly grows in those applications. As a result, units with larger power outputs are needed for tanks that have the same volume. Therefore, power losses and hot-spot temperatures should be minimized in the transformers used in these applications.

References

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