The energy efficiency of low voltage, dry type, distribution transformers is influenced primarily by the imposition of energy efficiency regulations and by the operational conditions imposed on the transformers. This study, in part, examines the energy efficiency regulations that govern the measurement and specification of energy efficiency for low voltage, dry type, distribution transformers and evaluates whether the requirement used to certify the transformer efficiency is optimized for minimizing power loss. In the U.S., regulations are mandated for transformer efficiency. With the demand for electricity increasing every year, improvement in transformer efficiency at the point of use under operational conditions will conserve energy.

This study investigates whether the current energy efficiency rulemaking, that establishes transformer efficiency at only one point on the load curve, provides the level of energy savings expected by government rulemakings, and evaluates alternate methods for specifying transformer efficiency. This study also attempts to characterize the operational load levels experienced by these transformers, including seasonal and daily load variations, and relates the operational load levels to the efficiency standard and alternate methods. The study also demonstrates the importance of considering transformers and distribution networks as part of a system when evaluating the implementation of other energy efficiency improvements, and how it impacts the optimization of power consumption within commercial facilities. Recommendations are presented for improving transformer rulemakings and for system considerations to realize higher energy savings in commercial and industrial facilities.