一种适用于自动准同期装置的改进傅立叶相位差算法

在微机自动准同期装置中,相位差的测量是同期判断的关键因素。目前国内大量采用零交法测量同期点两侧相位差,其在谐波等干扰条件下误差较大。相位差的傅立叶算法具有抗谐波干扰能力,但在同期点两侧频差较大时,存在计算误差。对不同步采样条件下交流信号的傅氏变换结果进行分析,对相位差的傅氏算法进行了改进,并进行仿真、实验,证明可以提高测量精度。目前该算法已经应用在具有同期功能的变电站测控装置中,获得了满意的效果。

An improved phase difference algorithm based on Fourier transform for quazi-synchronous device

The measurement of phase difference is the key factor in microprocessor-based automatic synchronizing device. So far the zero-crossing method of phase difference is prevailing domestically. But its deviation is considerable on the condition of harmonic disturbance. The Fourier transform algorithm can resist the harmonic disturbance. But the calculation deviation exists when the frequency difference between the two sides of the synchronizing closing points is great. The Fourier transform result of asynchronously sampled values of alternate signals is analyzed. The algorithm is developed. The digital simulation and test of the improved algorithm are done. It is proved that the improved algorithm can improve the measurement accuracy. The algorithm is applied in the substation automation measuring and control device with synchronization function. The effect is satisfactory.