Measurement of harmonic losses in transformers supplying nonsinusoidal load currents

The spread of the load control techniques based on power electronics is causing the increase of harmonic losses in power distribution systems. A digital method for the evaluation of these losses in power transformers, which only requires measurements taken at the transformer output terminals, is discussed. The accuracy of the method, along with the performance of a virtual-instrumentation-based instrument implementing it, is also discussed. The results of some experimental work are reported.