Transformer Parallel Connection Diagram. This gives us mixed connections. If two transformers of different voltage ratio are connected in parallel with same primary supply voltage there will be a difference in secondary voltages.
A three phase transformer is built for a specific connection and voltage transformation and the unit will have a nameplate with the internal connections shown. As the internal impedance of transformer is small a small voltage. Similarly v bn leads v bn by 30º and v cn leads v cn by 30º this connection is also called 30º connection.
The connection diagram of the parallel operation of a transformer is shown in the figure below.
As you re looking at the transformer you can see on the left the 6 5 2 1 and you can see how those are two separate pieces and if you connect 5 and 2 together then it s basically from top to bottom one series circuit. It is seen from the phasor diagram that the secondary phase voltage v an leads the primary phase voltage van by 30. The four basic connections are. In the case of mixed connections the ratio between the main voltages on the primary and secondary sides is not equal to the ratio between the number of turns.
