Research On Cable PD Location Based On Second Generation Wavelet And Transient Zero Mode

Power cable is the main component connecting power plants,substations and all levels of urban power supply and distribution network,and also the main carrier of short-distance power transmission and distribution.Compared with the traditional form of overhead lines,power cables have the characteristics of concealed installation position,stable operation and high durability,and little impact by the external environment in the process of operation.The cable rate of power supply and distribution system in a city can not only reflect the technical and economic level of power supply and distribution network in a certain level.At the same time,it is also of great help to improve the city's civilization,the city's appearance and the overall power operation environment.In order to solve the problem of poor denoising effect of PD signal and low positioning accuracy of PD power supply.Based on the wavelet analysis and transformation,this paper studies how to use the second generation wavelet algorithm based on the lifting scheme to complete the denoising of PD signal,and how to use the correlation analysis method based on the difference of the transient zero mode current to locate the PD power supply.Firstly,aiming at the problems of PD signal denoising and PD source location that need to be solved urgently in PD research,on the one hand,the noise and its characteristics contained in PD signal are analyzed deeply.Combined with the shortcomings of existing denoising methods,the second generation wavelet denoising technology based on improved lifting scheme is proposed to complete the noise reduction of PD signal.Secondly,based on the effective de-noising,the method of correlation analysis based on the difference of transient zero mode current is used to locate the partial discharge.On the one hand,the transient zero mode current method is used to process the PD signal,which makes the subsequent positioning operation more simple.On the other hand,the method of difference correlation analysis is used to complete the localization of PD power supply,to ensure that the PD signals collected in the process of localization calculation are directly transmitted from the PD point without any refraction and waveform distortion.This ensures the accuracy of the positioning.Then,using MATLAB simulation tool software,the theory and algorithm proposed in this paper are simulated and verified.Through the comparison of simulation results and the analysis of simulation data,the feasibility and superiority of the proposed method can be verified from different aspects.Finally,a set of PD de-noising and PD source location algorithms are implemented by hardware and software,and are applied in practical projects.The field test shows that the device and software designed according to the improved algorithm can solve the problem of PD location in application very well,which has a very good practical effect and promotion value.