sexta-feira, 4 de abril de 2014
EVALUATION OF AN EFFICIENCENT TRANSFORMER CORE DESIGN HEXATRANSFORMER
EVALUATION OF AN EFFICIENCENT TRANSFORMER
A Dissertation submitted to the Faculty of Engineering and the Built
Environment, University of the Witwatersrand, in fulfilment of the requirements
of the degree of Master of Science in Engineering.
The hexa-transformer is a three-phase transformer with a symmetrical core. The
transformer core consists of nine rolls of laminated steel bands, with the core legs
having a cross sectional shape of a hexagon.
Distribution transformers have inherently high efficiencies of up to 99%, however they are in continuous operation and have a long lifespan, hence their power loss cost is still significant. A small efficiency improvement can lead to a considerable amount of energy savings over the lifetime of the transformer. Symmetric core design has the potential to improve transformer efficiency. The aim of this dissertation is to evaluate a relatively new symmetrical triangular core transformer for use in the Eskom Distribution network in South Africa. The transformer is called the hexa-transformer. A three phase 100 kVA hexa-transformer unit has been purchased from Hexaformer AB in Sweden. The unit has been routinely tested. A 50% no-load loss reduction has been achieved. The transformer was also opened and examined. The results indicated sound manufacturing quality. The economic analysis indicated a life cycle saving of R 2 727.41 per transformer over a 25 year period when compared to a conventional E-core transformer of the same rating. It is recommended that Eskom consider these units for future implementation in their Distribution network. LINKS THESIS