基于广义双曲S变换的快速谐波检测算法

S变换凭借其优良的时频特性已应用到电力系统的谐波检测分析中,但仍存在检测精度不高、计算量大以及检测结果易受噪声影响的缺陷。为解决S变换存在的问题,对广义S变换中的HS变换进行了改进,提出了广义双曲S变换,并结合不完全S变换的思想,提出一种基于广义双曲S变换的快速谐波检测算法,该算法首先根据信号功率谱包络的动态测度检测出各次谐波的谐波次数,然后仅针对谐波对应的主要频率点进行广义双曲S变换,通过提取变换所得的双曲S复数矩阵中的特征量确定谐波的幅值、相位等信息。仿真结果表明,该方法能够快速检测出稳态或暂态谐波信号的谐波次数以及信号中各次谐波的具体参数,检测的精确度高,实时性好,而且对噪声的敏感度大大降低,为算法的实际应用奠定了良好基础。

Fast Harmonic Detection Based on Generalized HS-Transform

S-transform have been applied to the detection of power system harmonics with its excellent time-frequency characteristics, but there are still some large defects, such as poor detection precision, large amount of calculation and test results affected by noises. To solve these problems, this paper has improved HS-transform of generalized S-transform, and proposes a fast algorithm of generalized HS-transform combined with the idea of the incomplete S-transform. Firstly, it detected each harmonic frequency according to the dynamic measurement of signal power spectrum envelope, then it made generalized HS-transform corresponding to the major harmonic frequencies, and the characteristic quantities of the resulting HS complex matrix determined the information of the harmonic amplitude and phase. Simulation results show that this method can quickly detect harmonic frequency and the specific parameters of the steady-state or transient harmonic signals. The prosed algorithm has some benefits to the detection with high accuracy and good real-time performance, and its sensitivity to noise has greatly reduced, which lays a good foundation for the practical application.