Two 3-ϕ transformers can be operated in parallel if the _______ condition is satisfied.
1. Same voltage ratio and same voltage referring to the primary ratio and same voltage the transformer to be connected in parallel.
2. The phase displacement between primary and secondary must be the same for all transformers connected in parallel.
3. The phase sequence must be the same.1
Only 3 is correct
2
Only 1 is correct
3
Only 2 is correct
4
All 1, 2, 3 conditions are satisfied simultaneously.