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Three-phase Transformer Circuits Connection

Three phase transformers are used throughout industry to change values of three phase voltage and current. Since three-phase is used so often for power distribution systems, it makes sense that we would need three-phase transformers to be able to step voltages up or down. Also it is a large scale generation of electric power is usually 3- phase at generated voltage of 132 kV or some what higher. A three phase transformer is constructed by winding three single phase transformers on a single core. Transmission is generally accomplished at higher voltages of 110 kV, 132 kV, 275 kV, 400kV, 750 kV for which purpose 3- phase transformer are necessary to step up the generated voltage to that of the transmission line.

These transformers are put into an enclosure which is then filled with dielectric oil. The dielectric oil performs several functions. Since it is a dielectric, a nonconductor of electricity, it provides electrical insulation between the windings and the case. It is also used to help provide cooling and to prevent the formation of moisture, which can deteriorate the winding insulation.

Three phase transformers inner circuits Diagram :

These transformers are put into an enclosure which is then filled with dielectric oil. The dielectric oil performs several functions. Since it is a dielectric, a nonconductor of electricity, it provides electrical insulation between the winding and the case. It is also used to help provide cooling and to prevent the formation of moisture, which can deteriorate the winding insulation.

-:Three-phase Transformer Connection :

Three phase transformer core has three sets of windings. In this time various methodes are available for transforming 3- phase voltages. That is (a) From 3- phase voltages to higher or (b) 3- phase voltages to lower 3- phase voltages i.e. for handelling a considerable amount of power.

Here i want to described most common connection for easily understanding:-

  • Y-Y (STAR-STAR) Connection.
  • Δ-Δ (DELTA-DELTA) Connection.
  • Y-Δ ( STAR -DELTA) Connection.
  • Δ-Y (DELTA- STAR) Connection.
  • V-V or Open Delta Connection.
  • T-T or Scott connection.

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