基于DFT的同步相量相角测量改进算法研究

Research on An Advanced Algorithm to Detect Synchronized Phase Angle Based on Discrete Fourier Transform

目前同步相量的相角算法多采用离散傅里叶变换(discrete Fourier transform,DFT),传统DFT算法在非工频情况下的计算精度和实时性不佳。本文分析非同步采样下DFT算法的相角误差,提出一种将2个数据窗的DFT结果进行旋转构造出具有相反相角动态误差分量的相量,以尽可能地削减相角测量的动态误差,最后再进行相角固定误差补偿的改进相角测量算法。与传统相角量测算法相比,该算法较好地修正了相角动态误差,仿真实验结果表明,该算法测量精度高,实时性好,抗干扰能力强。

Most methods of phase angle measurements adopt discrete Fourier transform （DFT）algorithm, but traditional DFT algorithm has a bad calculation accuracy and real-time performance in the case of non-power frequency because of asynchronous sampling. This paper analyzed the mechanism of phase angle errors of DFT algorithm under the situation of asynchronous sampling, and proposed an advanced method to improve the performance of phase angle measurements. Through constructing two opposite dynamic phase error components ,The paper decreased the dynamic error as much as possible and compensating the constant phase error. Compared with traditional phase angle measurement method, the proposed method can get more accurate phase angle by rectifying the dynamic error and fixing compensation in the synchronous phasor measurement. The accuracy, effectiveness, and real-time performance of the proposed method was proved to reliable by simulations and experiments.