In order to improve detecting precision of characteristics of electric disturbance signals and suppress the interference of hybrid noise

a denoising algorithm based on variational modal decomposition（VMD） combined with wavelet threshold is proposed.Firstly

Hilbert transform is used to analyze the spectrum of interference signal

and the number of decomposed modal is determined by calculating the average instantaneous frequency value.Then

the noisy signal is decomposed by VMD and some of the partial modal components are screened to reconstruct signals.Finally

the remained noise of reconstructed signals is eliminated by wavelet threshold method.Compared with the available denoising algorithms

the experimental results show that the proposed denoising algorithm is more effective and can hold back the characteristic information during the disturbance period better.