Research On Single-phase Ground Fault Traveling Wave Ranging Technology In Complex Distribution Network

The fault location technology based on transient traveling wave is widely used in the transmission network,but due to the complexity of the distribution network,it is still in the stage of theoretical exploration and simulation experiment.The complexity of the distribution network mainly includes several aspects:1)there are many branchest in the distribution network,and the overhead and cable lines are mixed,whinch leads to the serious attenuation of the travelling wave.2)single phase power distribution technology has been developed,and many of the distribution network terminals adopt single-phase distribution,and the hybrid line structure makes the distribution network asymmetric.In addition,due to the complexity of distribution network structure,only within the substation layout is difficult to locate entire network fault detection device.Besides,It is expensive to deploy wave detection device on each branch line.Optimize the stationing also restricts the development of power distribution lines traveling wave distance measuring technology.To this end,this paper conducts research on several key issues affecting traveling wave ranging,mainly doing the following works:1.To solve the problem of wave head extraction of transient wave signal,the energy mutation from transient signal energy is used to identify the wave arrival time.First,the energy ratio function method is used to select the appropriate time window to obtain the energy ratio distribution of the transient signal.The first extreme point of energy change is selected as the center of the fault fuzzy region.By using the TEO energy operator method in the fuzzy area,the energy mutation moment can be accurately calibrated to extract the traveling wave arrival time.2.In this paper,the transmission characteristics of the line wave in the hybrid line and the coupling relation at the boundary point are analyzed.By using Karenbauer transformation and its inverse transformation,the process of traveling wave transmission is analysed,.The difference between the three phase branch and single-phase distribution branch is obtained,which helps to put forward sevral modulus time difference ranging method to calculate the fault distance.3.The distribution network has many branch line,more comprehensive and accurate project cost.Considering this,based on the actual engineering project,zero-line mode ranging principle is presented in this paper.Via the topology of the line topology,the initial wave-linear mode-linear mode-linear model is generated.The time difference between the modules measured by the whole network detection device is eliminated,and the false fault point is excluded and the fault branch is finally located.Then,the statutory location fault point is combined with multi-mode time difference.Based on the actual engineering project,this paper developed and designed a distribution network traveling wave ranging detection device,which can collect,process and upload the main station platform at high speed for the transient wave voltage data.This project also developed the main station platform of the distribution network traveling wave ranging system,which can receive the data of the whole network detection device,analyze the failure result and feedback the operator.Finally,it can improve the safety and reliability of distribution network effectively.