Research And Application Of Traveling Wave Fault Location Method And System For 35kV Distribution Line

In urban and rural areas,35kV distribution lines are mainly supplied by urban and rural areas,which are characterized by poor path conditions,mixed overhead lines and cables,and T-connection branches.This brings great difficulties to the fault location of the line,and the error of the current distance measurement method based on the measurement impedance principle is large.In order to further improve the speed of line troubleshooting,reduce the outage time and improve the reliability of power supply,it is necessary to adopt some new ranging principles,such as traveling wave principle,and then develop a fault location system for 35kV distribution lines.Based on the propagation mechanism of transient traveling wave on distribution lines,this paper analyzes the reflection and refraction characteristics of traveling wave and the main factors affecting the transmission characteristics of traveling wave.Considering that the phase shift of transient traveling wave is greatly affected by the line parameters,and the parameters of 35kV line are often calculated by theory,an on-line correction method of adaptive parameters is proposed.Because of the influence of the factors such as the mixture of cable and overhead line,T-junction branch,distribution transformer and so on,there are different degrees of distortion and distortion after the reflection of the traveling wave,resulting in the problem of low accuracy of the capturing of the traveling wave head.In this paper,the least mean square error(LMS)is used for filtering and then the integrated empirical mode decomposition(EEDM)method is used to deal with the traveling wave signal,so as to overcome the problem of modal aliasing,To ensure the accuracy of catching the arrival time of the traveling wave head.On this basis,a traveling wave fault location method based on adaptive parameter correction combined with LMS and EEDM is proposed to solve the problem of fault location for hybrid lines and T-connected lines.PSCAD/EMTDC simulation test shows that the proposed method is effective and accurate for fault location of 35kV hybrid lines and T-connected lines.Then,the traveling wave fault location system is developed.The hardware and software of the main station and the terminal are designed,and the function and performance of the fault location system are tested.The test results meet the design requirements.Finally,the traveling wave fault location system is deployed and applied in the 35kV distribution network in Huanghua District of Qinghai Province.The practical application and cases in the past year show that the traveling wave fault location method and system are correct,with high precision and practical value in engineering.