Research On Signal Detection And Information Processing Of Partial Discharge In Buried Cable

With the development of high voltage power system,the underground cable of cross-linked polyethylene(XLPE)is widely used.The underground cable usually USES the offline detection method,the power supply will have a certain impact on the power supply.Power cable life mainly is decided by its insulation performance,is the most main cable insulation aging caused by partial discharge,on the phenomenon of partial discharge detection can reflect the insulation performance of the cable from the side.Therefore,this paper attempts to develop a partial discharge online detection device to improve the situation by studying the local discharge phenomenon.The first partial discharge of power cable on the existing detection method in this paper is a comparative study,analysis the characterjstics of various methods,production method of partial discharge current sensor for the detection of power cable by Rogowski coil principle,analyzed the impact of various parameters on the coil,and the actual situation under the influence of cable length,resistance,capacitance interference on signal transmission parameters such as compression the rate caused by the designed power cable partial discharge detection device.For the information processing process of cable partial discharge detection,because there are too much interference,it is difficult to extract partial discharge signals real,so an efficient method for interference filtering of PD signals is necessary.Through the comparative study,this paper chose the denoising wavelet transform to the signal,the testing result shows that the wavelet analysis can be very good for local processing signals in time domain and frequency domain,the partial discharge signal and noise signal to distinguish,which laid a theoretical foundation for the inspection of the cable partial discharge measuring device design.Finally,in order to confirm the feasibility of the system designed in this paper,two substations were randomly selected to carry out on-site testing,and the local discharge of the cable outlet was detected.The test results show that the existing power station buried cable has good effect and no leakage fault occurs.