The following conditions are to be fulfilled before parallel operation of Transformers:-
Effects of percentage impedance on load sharing in parallel operation of :-
Voltage drop between no load to full load of transformer is determined the percentage impedance of the transformer. Now, we describe the effect of percentage impedance on load sharing in parallel operation. Let, Percentage impedance of Transformer 1 = Z1 % And Percentage impedance of Transformer 2 = Z2 %
Ans: The loads will be shared inversely as the impedances of the transformers expressed in percent of normal voltage.
Ans:Due to unequal voltage ratio, secondary voltage of the both transformer will be different resulting a circulating current will flow through the secondary winding of the both transformer. This circulating current will act as extra load of the transformer and cause heating of transformers even on no load condition of the transformers. And due to over heating of transformer , transformer may be damaged.
Ans:- In case of different percentage impedance for different ratings of transformers the percentage impedance have to be converted to the same basic kVA.
Ans:Not necessary but they should share the load in proportion to their ratings.
Do not connect the transformers at incorrect polarity in parallel, incorrect polarity results a dead short circuit. Hence, both the transformer will be damaged.