Study On Spatial Localization And Imaging Of Partial Discharge Based On Phased Array Technology

The accurate location of partial discharge power supply of power transformer is an important part of improving the long-term safe operation capability of power transformer.Partial discharge may occur in transformer insulation,which may damage the insulation and threaten the safe operation of power system.Therefore,it is of great engineering significance to study the location of partial discharge in transformer,which can be detected safely and reliably in insulation preventive experiment.Firstly,the basic theory of transformer partial discharge location method based on phased array theory,phased array technology and time difference location method are described.According to the basic principle of the phased-array antenna,which is the front end of the phased-array positioning system,the corresponding mathematical models of three kinds of phased-array antenna arrays are established.After the phased array antenna receives UHF signals emitted from the local discharge power supply,the signal is digitized by data acquisition equipment with high sampling rate.Aiming at the probabilistic estimation error caused by environmental noise and signal strength,the location method of local discharge power is adopted.Secondly,the steps of positioning discharge power points are studied,and the probabilistic positioning algorithm is used to detect and locate continuous local discharge power signals.In order to estimate TDOA more accurately,the estimation method can be divided into three steps: first,the threshold method is adopted to a rough estimate,acquire the discharge power signal location information,and add window to the rectangular.Then the cross-correlation method is adopted in the threshold value method to estimate on the basis of improving the TDOA estimation accuracy.Last,the interpolation cross-correlation method is used to get the TDOA estimation more accurately.Finally,the actual data simulation work based on MATLAB proves the superiority of the local discharge power location method of power transformer.