基于分段插值同步化算法的谐波测量

摘要

Due to spectrum leakage, traditional harmonic measurement methods based on FFT lead to a larger error in the measurement of the fundamental frequency offset signal or the unsteady periodic signal. Now this paper uses a method of time domain interpolation to reposition asynchronous sampling sequence, segments sequence and analyze it respectively by using linear interpolation algorithm or Hermite interpolation algorithm according to the sequence of second difference quotient. Then two situations that the fundamental frequency offset is fixed and fundamental frequency is fluctuating are calculated. The results show that piecewise interpolation synchronization algorithm can be applied to the above two cases. Taking computational efficiency into account, it can meet the accuracy requirement of GBT 17626.7-2008 at the same time. The piecewise interpolation synchronization algorithm is a kind of practical method.%传统的基于FFT的电力谐波测量方法由于频谱泄漏问题，在测量基频偏移信号或者频率不断波动的非稳态周期信号时存在着较大的误差。现采用一种时域插值的方法对非同步采样序列进行重新定位，依据序列的二次差商大小对信号进行分段并分别采用线性插值和 Hermite插值两种算法进行二次同步化。在基频偏移固定和基频不断波动的两种情况下进行仿真计算。结果表明，分段插值同步算法能够适用于上述两种情况的谐波测量，在兼顾计算效率的同时，满足了GBT 17626.7-2008国标规定的精度要求，是一种具有实用性的方法。