Parallel operation problem
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Question: Is it feasible to operate two 10/0.4 KV transformers in parallel, with the low-voltage sections connected to each other through a bus bar? What are the disadvantages?
The conditions for parallel operation of transformers are met when the output voltage, connection group, and short-circuit impedance are all identical; in such cases, the transformers can be operated in parallel.
Reply to 2# czywqa: Should we consider the issue of phase difference?
For transformers to be operated in parallel, in addition to the transformer ratios, short-circuit impedances, wiring configurations needing to be identical, and the capacity ratio not exceeding 3:1, the most important factor is that the system must permit parallel connection of the high-voltage sides of the transformers. It’s the issue of closing the loop in the system! If the system does not allow ring connection, the transformers cannot be connected in parallel, even if they meet the requirements regarding those parameters!
So what conditions must be met on the high-voltage side in order to enable parallel connection? Can someone explain this?
The 4th floor is correct; parallel operation can be carried out as long as the conditions for parallel operation are met. Attention should be paid to the phase sequence when putting it into operation
When transformers are operated in parallel, in addition to meeting the conditions mentioned on the 4th floor, the parallel switching devices must be capable of protecting individual transformers, and a parallel protection cabinet must be installed between the cabinets.