Condition:
1. Voltage ratio must be same both side.
2. Frequency also be same.
3. Phase sequence of 3-phase 'R' 'Y' 'B' must be same.
Advantages:
1. Load distribution of Transformer will equal.
2. Service continuity not effected.
3. Maintenence of the Transformer will be perform without effected on load.
Disadvantages :
1. Cost of protection and the Transformer will more.
2. Land cost will slso increased.
