Parallel operations of Single phase Transformer

Today's topic is parallel operations of single phase transformer:-

Parallel operations of single phase transformer- It is required to connect a second transformer in parallel with the first transformer if the load exceeds the rating of the transformer. The primary winding are connected to the supply bus bars while the secondary windings are connected to the load bus bars. In this paralleling of transformer, similar polarities of the transformer should be connected to the same bus bar. Otherwise the emf (Electro magnetic field) is induced in the secondary winding with incorrect polarities with produced the equivalent of a dead short circuit.

Parallel operations of single phase transformer

This are are the most important condition for parallel operations of transformers:

1.The voltage rating of the both primary and secondary of the transformer should be identical and small differences are permissible if the resultant circulating current can be tolerated.

2.The connections of transformer should be proper with respect to their polarities.

3.The percentage impedance should be equal in magnitude and the X/R ratio must be same the avoid circulating current and operation at the different power factors.

4.The equivalent impedances must be inversely proportional to the respective KVA ratings.

The above condition must be satisfied by the paralleling transformers of identical ratings of the same model with different KVA ratings of even the same model and these are slightly modified.