The measurement and evaluation of distribution transformer losses under nonlinear loading

Harmonic currents, generated by nonlinear electronic loads, produce ´penalty losses´ in every element of an electrical distribution system. These harmonic-related losses reduce system efficiency, cause apparatus overheating, and increase power and air conditioning costs. Harmonic currents effectively de-rate existing systems and, when accommodated, add substantially to the capital cost of new distribution systems. The measurement and evaluation of transformer losses under linear and nonlinear load conditions will be discussed. In addition, typical financial benefits that result from the application of high efficiency harmonic mitigating distribution transformers, under nonlinear loading, will be calculated.