改进ITD-LS结合奇异值差分谱的间谐波快速检测方法

摘要

间谐波检测技术是电力系统谐波治理的重要工作内容，文章提出一种改进ITD法结合奇异值差分谱的快速高精度检测。通过改进ITD法可以直接根据含有系统特征信息的量测数据进行参数辨识。首先利用奇异值差分谱进行系统定阶；然后应用改进的ITD算法直接对含噪信号进行精确检测从而得到各谐波的实际频率；采用最小二乘法（ Least Squares，LS）对各间谐波分量的幅值进行精确检测。改进ITD法以SSI法的协方差矩阵（ Toeplitz）为输入数据，克服了数据处理方法不准确性带来的误差，提高了参数辨识精度。与SSI法相比，改进ITD法精度没有降低，同时缩短了计算时间。仿真结果表明：该方法计算速度快，检测精度高，抗噪声能力强，验证了所提方法的可行性和有效性。%Inter harmonic detection technology is an important content in power system harmonic suppression. A quick and high-precision detection method based on an improved ITD method combined with singular value difference spectrum has been proposed in this paper. By improving the ITD method,the system parameter identification can be a-chieved directly according to measured data with feature information. Firstly,the singular value difference spectrum will be used to make decision of the system order. Then,the improved ITD algorithm will be adopted to perform the high-precision detection for the noised signal so as to obtain the actual frequency for each harmonic. The Least square method( further Squares,LS)will be used to detect the amplitude of harmonic component with high precision. The im-prove ITD method takes SSI covariance matrix( Toeplitz)as the input data,which will overcome the error caused by the inaccurate data processing method so as to improve the parameter identification. Compared with the method of SSI, the improved ITD method accuracy does not decrease,and it will shorten the calculation time as well. Simulation re-sults show that the method has the advantages of fast calculating speed,high precision and strong ability to resist noise,which verify the feasibility and effectiveness of the proposed method.