On the definition of total harmonic distortion and its effect on measurement interpretation

The existence of two different definitions for total harmonic distortion (one in comparison to the fundamental and one in comparison to the signalʹs root mean square) might cause ambiguity and misinterpretation of measured data. The difference between those definitions is stressed out in this letter. It is suggested that total harmonic distortion measurements in the context of power systems should always adopt the first definition and never the second.