Advantages of Parallel Operation of Transformers
Parallel operation of transformer because of following advantages
- Maximum power system efficiency: Power system loads always varies to maintain its efficiency we operate transformers in parallel because transformer gives the maximum efficiency at full load,if we use single large transformer,load on the large transformer always varies so it will operate with low efficiency. In other hand if we operate small units in parallel we can switch on/off as per load demand and we can maintain high efficiency.
- Ease of electrical power switching: Scheduling the power with single large transformer will become difficult because of it's high rating and distribution system will be connected ,controlled by a single transformer we can avoid this problem using parallel operation of transformers.This also improves power system reliability,flexibility.
- Economical Issues /Non-availability of large transformer: If a large transformer of required rating is unavailable we can go for small rated transformers which can perform better than single large unit. And large transformer operating costs will be more than parallel operation of single phase transformers.
- Easier transportation: Transportation will be very easy for small transformers: If installation location is far away from transformer manufacturing/selling point.So parallel operation of transformers is to be encouraged.
Conditions for Parallel Operation of Transformers
- The voltage ratings and voltage ratios of the transformers should be the same.
- Transformers should be properly connected with regard to their polarities.
- The per unit or percentage impedance of the transformers should be equal.
- The reactance/resistance ratios of the transformers should be the same.