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.