'Parallel operation of transformers' helps in energy conservation:
The transformers operate near their maximum efficiency at around 70 % to 100 % of their rated loads. For a huge load system drawing highly varying powers at different times supplying from single transformer will be uneconomical and inefficient at low loads. Hence to operate the system at highest efficiencies as much as possible parallel connected transformers are utilized such that at lower power requirements one of those in parallel will supply at around its maximum efficiency while the other is switched off thus saving its low load losses. This is done as per the requirements of the loads. When more power is needed the other transformer if of higher rating may be put in service while the first one may be switched off.