电力系统频率测量存在精度与实时性无法同时满足的问题,因此提出一种多水平集单周期频率测量方法.首先采用数字低通滤波器滤除信号中的高频干扰,其次采用三次样条(not-a-knot)插值法对所设阈值附近的采样点进行重构,然后利用多个阈值与信号的交点进行频率估计,最后运用最优组合加权法得到电力系统频率估计结果.该方法是一种时域频率估计方法,具有计算量小、精度高的特点,可在单周期内实现电力系统频率的准确测量.仿真和实际测量实验结果验证了多水平集单周期频率测量方法的有效性和可行性.%Aiming at the problem of the trade-off between accuracy and real-time performance in power system frequency estimation,this paper proposes a single-cycle frequency measurement method based on the multi-level set.Specifically,the high frequency interference signals are removed by the digital low-pass filter before reconstructing the sampling points around the threshold by using the cubic spline(not-a-knot) interpolation method,and then obtain the frequency estimation results through the optimal combination weighting method.This method is classified as time-domain frequency estimation,and is characterized by robust toward the accuracy of the measurement and low computational effort,which enables power system frequency to get accurate measurement in a single cycle.The reliability and effectiveness of this method are proved by the theoretical analysis as well as the simulation studies.
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