基于频域滤波的间谐波在线检测算法

在线实时检测谐波、间谐波的幅值和相位等参数是改善电网电能质量的基础,而在线检测技术的关键是计算速度和精度.针对基波和谐波对间谐波频谱泄漏的影响,提出一种基于频域滤波的间谐波在线检测算法.该算法将信号分为基波、谐波与间谐波,先采用双峰谱线修正算法计算出谐波及基波参数,并在频域将谐波以及基波信号滤除,消除其对间谐波的频谱干扰后,再进行间谐波检测.该算法在保证测量精度的基础上,只需计算1次FFF（fast Fourie transform）,显著降低了算法所需的计算量,易于在电能质量实时在线监测装置中应用.在Matlab中比较了不同采样周期下的普通双峰谱线修正算法、基于时域和频域滤波的改进算法,验证了所提出算法的精度和计算速度.

On-line Detection Algorithm for Interharmonics Based on Spectrum Domain Filtering

Magnitude and phase on-line monitoring of harmonics and interharmonics are the foundation of power quality improvement while speed and precision of the algorithm are the keys of on-line monitoring techniques. This paper studies the spectrum leakage of harmonic and interharmonic and then proposes a rapid on-line detection algorithm based on spectrum domain fihering. The algorithm divides the original signals into three parts those are fundamental signals, harmonic signals and interharmonic signals, and then filters the harmonic signals in frequency domain so as to eliminate the spectrum interference to the interharmonie signals. Thus, only one time of FFT （Fast Fourie Transform） calculation is needed, which reduces calculation burden of the algorithm remarkably with a good precision and makes the algorithm easy to be implemented in on-line monitoring device. A comparative simulation of four different interharmonic detection algorithms was conducted in Matlab to verify the feasibility and superiority of the proposed algorithm.