同步频移Zoom-FFT谐波检测方法

Methods of Harmonics Test of Synchronization Shifting Frequency Zoom-FFT

电力谐波测量大都采用N倍基波预测采样率FFT方法,这在电网频率变化的情况下会带来误差,文章提出频率跟踪同频伸缩FFT算法,在计及实测频率与固定采样频率情况下,准确分析谐波和间谐波成份,同时研制了多通道并行电能质量测试系统,实现了主从结构测试与分析系统平台,在此基础上建立了连续的滑动窗口的Zoom-FFT谐波检测实用系统,测试表明:通道动态范围高于120dB,测试精度达到0.01%。该方法对于谐波动态监测具有参考价值。

Power harmonics measurement often used FFT with N times of predict frequency.It will bring errors when power frequency is changed.This paper proposes a synchronization shifting frequency Zoom-FFT,with consideration of real test frequency and fix sampling frequency,which can get accurately inter-dynamics and dynamics.An implemented test and analysis system with master-slaver structural in the parallel test system is given.In this platform the master engine software controls all stations to realize the functions of the multi-channel synchronization sliding window Zoom-FFT.The system DR is more than 120dB and test accuracy more than 0.01%.This system may be served as a reference in the side of requirement of dynamic monitoring power quality.