Parallel operation of transformers:
Parallel operation two or more transformers is can be achieved by connecting primary winding to common supply input and secondary to common load bus.sometimes parallel operation is economical to connect numbers of smaller rated transformers in parallel than installing a high rated electrical power transformer.so we go for parallel operation of transformers.
Why Parallel Operation of Transformers is required?
The first question why we need to operate transformers in parallel,reasons explained below.these are the main uses of Parallel Operation.
1.To maximize efficiency of the electrical power system.
2.To maximize electrical power system availability.If numbers of transformers operated in parallel, we can shutdown or run any one of them for maintenance purpose,this gives various power output.
3.To improve power system reliability.we can trip our load if any fault occur parallel operation gives reliable power supply.
4.To improve electrical power system flexibility.
Conditions For Parallel Operation of Single Phase Transformer:-
When want to operate two or more transformers in parallel, they must satisfy some conditions for high efficiency. These are the must followed conditions for parallel operation of transformers.
1.The first condition to be satisfied is voltage ratio of all connected transformers must be same.i.e their output voltage values may differ from each other but E2/E1 of first transformer must be equal to E2/E1 of second transformer.
2.Transformers should be properly connected with regard to their polarities.The polarity of all connected transformers must be same in order to avoid circulating currents in transformers.
3.The per unit or percentage impedance of the transformers should be equal.
4.The reactance/resistance ratios of the transformers should be the same.
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