Design of Transformer with Flexible Vector Group Combinations and Adjustable Voltage Levels

An electrical power transmission and distribution systems uses many transformers in their substations with different vector groups and voltage levels. To assure reliability of the supply, the utility companies need to maintain spare transformers of all those vector groups and voltage levels. This results into increased cost and occupies lot of space. This paper describes design of a transformer, which enables different vector group combinations with different voltage level operations. Transformer design with YNd1 and YNyn0 vector group combinations is studied. Percentage winding reactance is computed using analytical, two dimensional (2-D) magnetostatic finite element method (FEM) and circuit approach. With proposed flexibility of transformer connections, number of spare transformers can be reduced, thus saving of initial investment and space can be achieved.

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