用于PD信号去噪的dbN序列有效复小波构造研究

根据正交小波构造的条件,采用替换实小波共轭复根的方法,构造了与dbN序列正交实小波具有相同幅频特性、不同相频特性的复小波,指出了共轭复根数与构造复小波数的关系,给出了构造有效复小波应满足的条件,即共轭复根的虚部绝对值小于0.01且与实部绝对值之比也小于0.01时,不能构造有效的复小波。同时,用构建的dbN序列复小波对4种典型仿真局部放电(PD)信号的去噪研究表明,不同类型的仿真PD信号对应有dbN序列去噪最优复小波,而且与相应的实小波去噪进行了对比,进一步证明了复小波用于PD信号去噪的优越性。

Constructing dbN complex wavelets for PD signal denoise

According to the conditions of orthogonal wavelet construction, the complex wavelets are constructed by replacing the conjugate complex roots,which,compared with dbN real orthogonal wavelets,have the same amplitude spectrum and different phase spectrum. The relationship between the number of conjugate complex root and the number of complex wavelet that can be constructed is indicated. The conditions of constructing complex wavelets are given:if both the absolute value of imaginary part of conjugate complex root and its ratio to the absolute value of real part are less than 0.01,the valid complex wavelets can not be constructed. The dbN complex wavelets are constructed to denoise four typical simulative PD(Partial Discharge) signals. Results show that different types of simulative PD signal have different optimal complex wavelets and the application of complex wavelet in PD signal denoise is more favorable than the real wavelet.