Research On Fault Location Scheme Of 10kV Distribution Line

The grid structure of 10 k V distribution line is complex,where overhead line-cable mixed lines are mostly used for power supply.There are different forms of feeder branch structure to overhead wire and cable.In addition,the fault detection is difficult attribute to the small fault current under the operation mode of small current grounding,resulting in the fault location difficulty which always puzzles scholars.As the load is directly connected with the power grid,10 k V distribution line fault locating is related to national normal production and living power,we must pay attention to the location of,quickly and accurately,it is important for improving the safety and reliability of power grid operation.This paper starts from the traveling wave two-terminal fault location and locates fault of complex distribution lines at different levels.This paper has made analysis on the fault segment selection method and fault point location.The fault selection methods suitable for multi branch distribution overhead line and multi branch cable distribution respectively are proposed,and then a set of 10 k V for multi branch distribution line fault positioning scheme is put forward.Firstly,multi branch circuit structure of 10 k V power distribution overhead line and cable made in this paper,the concept of cable branch domain,in order to simplify the circuit structure;then analyzes the structural characteristics of two branch lines,with a transmission path presentation form fault initial traveling wave icon,to explore the time difference between traveling wave fault location information and connotative relationship.Then the time difference between the known theory based on the proposed overhead line position observation matrix feature fault region judgment method and based on the method of cable fault based on the time difference between multiple selections.This paper starts from the structure of the overhead line type T circuit,fault section characteristics of fault initial relationship between the measured speed and the actual wave velocity indicated by the proposed overhead line wave velocity comparison method based on fault section.Finally,in accordance with strategy of progressive location and gradual location of fault location,a comprehensive fault location scheme for 10 k V multi branch distribution line is proposed.This paper uses the PSCAD software to build 10 k V distribution line simulation model and makes simulation of integrated positioning scheme proposed in this paper.We observed dozens of microsecond fault waveform changes with MATLAB,and obtained the maximum value of the sudden change modulus by wavelet transform to accurately capture the arrival time of traveling waves.The simulation proves that the scheme can effectively locate different fault points.Compared with the simulation data,we can see that the scheme is less affected by the fault type,the initial phase angle and the transition resistance,and the location accuracy is high,which satisfies the location requirement of 10 k V multi branch distribution line.The integrated positioning scheme of 10 k V distribution line fully considers the complexity of traveling wave propagation under the branch structure.Without detection of second wave,it has high positioning accuracy.Along with the improvement of the traveling wave acquisition equipment performance and clock synchronization precision,this positioning scheme will have higher positioning accuracy.