When a 1-phase transformer is connected in parallel, there are four conditions for proper parallel operation, but when two or 3-phase transformer paralleling is done, there are two additional points along with those four conditions applied for 1-phase. Statement 1 - The phase sequence must be the same. Statement 2 - The phase shift between primary and secondary voltages must be the same for all transformers connected in parallel. From the above two Statements (s), which is/are the correct conditions in this regard? Correct Answer Statement 1 is true, Statement 2 is true Condition for Parallel Operation of Three Phase Transformers: Following are the necessary conditions for parallel operation of 3 phase transformers: The line voltage ratio of the transformers must be the same. The transformers should have equal per unit leakage impedance. The ratio of equivalent leakage reactance to equivalent resistance should be the same for all the transformers. The transformers should have the same polarity. The above four conditions are also applicable for the parallel operation of single-phase transformers. Apart from the above four conditions, there exist two more conditions that should be fulfilled for parallel operation of three-phase transformers: The relative phase shift between the secondary line voltages of all transformers should be zero. The phase sequence of secondary line voltages of all the transformers should be the same.