Research on Measurement Method of Broadband Multi-frequency Signal in Power System

Recent years, with the widespread application of power electronics technology in the power grid, the pollution of harmonic and inter-harmonic of power grid caused by it have become more and more serious. In this paper, a real-time broadband multi-frequency signal measurement system based on synchronous phasor measurement unit (PMU) is proposed to estimate the synchronous harmonic and inter-harmonic phasors in the power system. In the proposed measurement system, the original signal is acquired by high-speed synchronous sampling technology. The calculation of the fundamental wave phasor is based on the model recommended by the IEEE Std C37.118.1-2011 to meet the requirements of the dynamic and static measurement performance. The calculation of harmonic and inter-harmonic phasors is extracted by the fast fourier transform (FFT) algorithm with Hanning window. The correction algorithm of frequency, amplitude and phase is given to compensate the spectral leakage and the picket fence effect caused by the discrete signal FFT. The feasibility and accuracy of the proposed measurement method are verified by MATLAB simulation experiments.