基于固定采样频率的相量精确测量算法

Study on the precise phasor calculation based on constant sampling frequency

离散傅里叶(DFT)算法是电网实时运行系统中进行相量测量的基本算法.由于相量测量装置(PMU)对相量测量同步性的要求,其采样频率应保持为常数,当系统频率变化时,相量的计算会出现误差.笔者分析了采样频率固定而系统频率发生偏移时的相量测量误差的变化规律,指出相角的测量误差与数据窗中相量参考点的选择有关,并提出一种利用系统频率对相量进行校正的新方法.仿真实验的结果表明,该方法可以使相量的测量误差大大降低.

Discrete fourier transform （DFF） is the basic method for measuring the phasor of power system in real-time. The sampling frequency of PMU is constant because of the synchronization of its phasor measuring. As system frequency changes, the error of measuring phasor is avoidless. In this paper the variation of measurement error is analyzed and the relation between error of angle and the selection of reference point in the data window summarized. A new method to revise the phasor by the measuring frequency is presented. Simulation result shows that the measuring error of magnitude and angle can reduce greatly using this method.