Total harmonic distortion (THD) is a unitless measure of how distorted the current and voltage waveforms are compared to an ideal, sinusoidal waveform operating at specified line frequency (50 Hz or 60 Hz, depending on location). If your MCC, VFD, or submeter reports THD, report it to Motors@Work in this field as a percentage (i.e., for 4.04% or 0.0404, enter 4.04).
Motors@Work generates an alert if THD exceeds 4% in accordance with NEMA recommendations.