非同步采样下电网谐波分析方法的探讨

Study on the approachs of electrical harmonic analysis for asynchronous sampling

介绍了加窗插值法和准同步法在电力系统谐波参数估计中的应用。首先分析了非同步采样时FFT算法频谱泄漏的主要原因。然后通过对常用窗函数的特性探讨,给出了基于海宁窗和布莱克曼窗下的幅值和频率估计公式。同时基于准同步法的基本原理,给出了幅值计算公式。仿真结果表明,三种方法都能显著减少频谱泄漏。最后结合精度,误差频率特性和算法易实现性的比较,对几种算法的实际使用给出了建议。

The estimation of electrical harmonic parameters by using the quasi-synchronization and interpolated FFT are introduced. The main factor of spectral leakage is conducted when the sampling would be non-synchronous. The computing formulas for the harmonic parameters are given based on the features of Harming Window and Blackman Window. The computing formulas are given based on the method of quasi-synchronization as well. Simulation result demonstrates that the expected precision is achieved with the above three methods. Compared with the precision, error features with variable frequency and practicability of the algorithm, a suggestion is proposed in engineering practice.