Reference Standard for Harmonics and Nonsinusoidal Power Measurements

In this paper, a method for the measuring the harmonic amplitude and power of nonsinusoidal signals, which utilizes two synchronized high-precision digital voltmeters, is described. The harmonics of voltage and current waveforms were computed from digital samples and compared with the values obtained from thermal converters. The software developed, which is based on the fast Fourier transform algorithm, computes current and voltage harmonics with uncertainties of less than 10 × 10^-6 of fundamental. The uncertainty of the power harmonics is 17 μW/VA . The system can be used as a reference system for calibrating harmonic analyzers at power frequencies.