Research On Single-phase Grounding Fault Diagnosis And Location Of Transmission Lines Based On Bayesian Network And TEO

In recent years,with the rapid development of power grid automation,the requirements of power system for stable operation are higher and higher.As an important part of power system,the transmission line plays an important role in the safe and stable operation of power system.Therefore,the research on fault diagnosis and location of transmission lines is of great significance.In this thesis,the 110kV transmission line is taken as the research object,and the single-phase ground fault diagnosis of the transmission line is studied.Firstly,several methods of transmission line fault diagnosis are compared and analyzed.Then,Bayesian network is selected to diagnose transmission line fault.In this thesis,two kinds of network models are determined.The input node of the first model is the cause of the single-phase ground fault of the transmission line,and the input node of the second model is the fault characteristic of the single-phase ground fault of the transmission line.Finally,two different models are built in the Netica simulation software.The first model is simulated by expert knowledge,and the second model is simulated by data learning.The simulation by expert knowledge is complex,but the final result is accurate;the simulation by data learning is simple and convenient,but the final result will be certain errors.In the end,the two models are analyzed in detail by simulation software.After the fault diagnosis of single-phase ground fault of transmission line,the fault location of single-phase ground fault of transmission line is studied.In this thesis,the traveling wave method is used to study the fault location of transmission line.The 110 kV transmission line is taken as the research object,a fault location formula which is not affected by the wave speed is derived,and the influence of wave speed on the fault location result is eliminated.Then,wavelet transform and Teager energy operator(TEO)are used to extract the fault traveling wave.Firstly,the resolution of the fault traveling wave is improved by wavelet transform.Then,a time point is selected to extract the energy feature by using TEO to judge the time when the initial traveling wave reaches both ends of the line.Finally,the fault distance can be obtained by the time when the fault occurs and the time when the initial traveling wave reaches the both ends of the line,which greatly improves the accuracy of the fault location result.