Parallel operation of transformer

Sir can you teach circuit design

Yeah, parallel transformers are like two separate transformers on one live wire. The ground points can differ. Transformers tend to be more tricky in series, unless they share the same flux (core). Then it's a simple matter in tapping the secondary at some point to get a different voltage

parallel transformers means primary and secondary of both are connected parallel. voltage ratio and polarity are most important and must be equal for successful operation. Per unit leakage impedances must be equal for high efficiency but not the most important criteria, but should approximately equal.

Yes, correct! But it's unwise to place voltage sources in parallel, because every imbalance will result in current flow from the higher potential to the lower one. This holds true especially for nonlinear devices, such as transformers. Assume this scenario. You've somehow managed to even out the potentials between the transformers (which is extremely difficult), and one of the two transformers goes into saturation prematurely. The voltage drop due to the saturation, will cause high currents to flow from the other transformer (which is already close to saturation). Worst case scenario is, both transformers get stuck in a perpetual saturation (almost like a short circuit) and sooner or later the weaker one blows out.

Yes, circulating current is proportional to voltage difference between two transformers and inversely proportional to their leakage impedances. And as leakage impedance is roughly 2-5%, circulating current is very huge. It's very tough task to get them parallel operating over long period of time.

Yeah, emphasis on continuous operation. Stuff in real life decay. They might work normally in the beginning, and after time go out of sync