Improved electric power measurement method and its application while harmonic exists

To reduce the electric power measurement error caused by harmonics, an improved electric power measurement method based on triangular self-convolution window is presented in this paper. First, the sampled voltage and current signals are weighted by triangular self-convolution window. Then, the harmonic parameters of voltage and current signals are estimated with windowed interpolated FFT algorithm. Last, the electric power of harmonics can be measured using Budeanu's definition. Simulation experiments were carried out using the Hanning window, Blackman-Harris window, Rife-Vincent (I) window and triangular self-convolution window under unsynchronized sampling condition; experiment results demonstrate that the effect of fundamental frequency variation and white noise can be restrained by using triangular self-convolution window. The application and experiment results in 3 phase multifunction harmonic power meter show the usefulness and accuracy of the presented method.