Application of Blackman-Harris window and interpolation algorithm in transformer terminal unit

Abstract

In order to reduce harmonic analysis error caused by spectral leakage and picket-fence effect, the Blackman-Harris window and interpolation algorithm is applied to the harmonic analysis for the voltage and current signals acquired in transformer terminal unit (TTU). The principle of the Blackman-Harris window and interpolation algorithm is introduced, and programs about the algorithm and the fast Fourier transform (FFT) algorithm are written. Voltage signals with different frequencies are numerically generated and the real voltage signal is measured. The FFT algorithm and the Blackman-Harris window and interpolation algorithm are used to conduct harmonic analysis on those signals. The results reveal that the latter can accurately obtain the signal frequency, the amplitude and phase of each harmonic. It can meet the requirements of TTU on harmonic analysis. This work provides a reference for power quality analysis.