一种新的电力系统谐波间谐波两步检测法

Harmonic and inter-harmonic detection method based on neighboring spectral offsetting and windowed TDA in two stages

提出了一种新的基于邻近谱线抵消及加窗TDA的谐波间谐波两步检测法。IEC对于谐波间谐波检测推荐的采样窗口长度为十个周波,在此前提下,研究了同步采样下谐波和间谐波之间的频谱干扰特性,提出采用两步法对谐波和间谐波分开进行分析。对于各次谐波,利用邻近谱线抵消手段抑制了间谐波对其频谱的干扰;间谐波的时域对应TDA后的差分信号,考虑到各间谐波频谱之间的干扰及栅栏效应,通过加窗双谱线插值提高间谐波检测精度;当某一间谐波频率与谐波频率较为接近时,提出加窗TDA法抑制拟谐波偏差信号主瓣对间谐波的影响。通过仿真分析表明,在同步采样条件下,此方法对于谐波和间谐波有着较高的检测精度。

This paper presents a new method for detecting harmonics and the inter-harmonics, it is based on neighboring spectral lines offsetting and windowed TDA. The recommended standard of IEC about the length of sampling window is ten fundamental periods. This paper investigates the spectral interruptions between harmonics and inter-harmonics under synchronized sampling, detects the harmonics and inter-harmonics separately in two stages. For harmonic detection, it uses neighboring spectral lines to offset the spectral interruption by inter-harmonics. For inter-harmonic detection, windowed interpolated DFT to eliminate the spectral leakage and fence effect. When there is an inter-harmonic close to a harmonic, a windowed TDA method is presented to improve the inter-harmonic detection accuracy. Through the simulation analysis, the validity of the proposed method is proved.