Efficiency and Loss Evaluation of Large Power Transformers

All power transformers have very high energy efficiency—the largest are probably the most efficient machines ever devised. However, there is still scope for improvement. Any improvement in the performance of large transformers offers the potential of genuine economic benefits because their throughput and their continuous duty mean that the energy they waste is likewise enormous.

This Application Note discusses the nature of power transformer losses and evaluates those losses from an economic and ecological point of view. There is no general rule on how to design a power transformer for minimum life cycle cost. It has to be approached case by case, based on an estimate of the load profile. This Application Note also tackles the question whether an over-sized transformer is always an energy efficient transformer, and  it contains a chapter on the choice of the conductor material.

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  • A small energy efficiency gain can result in large energy and cost savings in power transformers because of their large throughput and continuous duty.
  • Designing a power transformer for minimum LCC should be approached case by case, based on an estimate of the load profile.
  • Simply over-rating the transformer will almost always lead to user benefits.
  • Copper is the ideal material for the magnet wires because it has superior electrical conductivity, along with other technological advantages.