An improved double peak interpolation algorithm based on the dynamic harmonics and its application in harmonic power metering

The fast Fourier transform (FFT) exists a higher error on non-synchronous sampling, which makes harmonic energy couldn´t be obtained accurately in harmonic power metering. In order to reduce the influence of non-synchronized sample on FFT and improve the precision of power metering, this paper has adopted Hanning window function, analyzed and deduced interpolating windowed algorithm carefully. For further eliminating the leakage effect, interpolating algorithm which adopts dynamic signal frequency is presented. Simulation results show the improved algorithm has a high precision, and can be easily realized. On this condition, power metering model which separates the fundamental from the harmonic is constructed. Users could measure the fundamental energy and harmonic energy in real time.