Study On Fault Locating Of Automatic Blocking And Continuous Transmission Lines Of Electrified Railway Based On Segmental Distance Discriminant Method

The railway automatic blocking and continuous transmission lines is an indispensable part of railway power supply system,which provide power supply for the automatic blocking signal along the railway and other non-traction electrical equipments.However,the automatic blocking and continuous transmission lines are usually operating in complex and changeable environment,which can easily cause various line faults.Once the line faults occurred,it will make seriously affection on the normal operation of railway signals,and even cause accidents,resulting in unimaginable consequences,.In order to ensure the normal operation of the railway automatic blocking and continuous transmission lines,it is necessary to locate the fault point quickly and accurately and remove the fault threat.Therefore,the fault location problem of the hybrid transmission line,which is the key and difficult point in the problem of the automatic blocking and continuous transmission,was discussed and studied in this paper.Firstly,this paper described the transient characteristics of the fault traveling wave,analyzed the linear mode component and the zero mode component in various fault cases,and selected the optimal mode component.Wavelet transform theory is introduced into fault signal detection as a means of signal processing.The optimal wavelet was determined by the simulation comparison of the singularity detection ability of wavelet analysis.Then the wavelet modulus maximum theory was used to complete the detection of the singularities of the fault traveling wave,which determine the absolute time of transient traveling wave to the bus line measurement terminal.According to the specific parameters of a section of the Beijing-Harbin line,an automatic blocking and continuous transmission lines simulation model was built based on MATLAB.A method of wave velocity independent ranging was applied to fault location of single overhead line.In order to illustrate the effectiveness of this method,various fault situations were simulated,and the simulation results were compared with the traditional single-ended and two-terminal location methods.Afterwards,a method of distance measurement based on segmented distance discrimination was proposed for the line structure with hybrid transmission lines in the automatic blocking and continuous transmission lines.In addition,the wave velocity normalization method,time-difference search ranging method and the method which was proposed in this paper were compared through simulation.The results show that this method is superior to the other two traditional location methods,and is not affected by grounding resistance,fault type and other factors.On this basis,the faults of various fault types and noise conditions were further measured.The results showed that the algorithm is not affected by the grounding resistance,fault type and other factors,and still has applicability in the case of noise.Finally,the design of the fault location system was completed,and a simulated 10 kV railway automatic blocking and continuous transmission lines were built under the laboratory conditions.The dynamic simulation experiments for all kinds of faults were carried out.In order to better verify the applicability and feasibility of this algorithm to the local site,an on-site manual grounding experiment was performed on a certain section of the Beijing-Harbin Line in the Beijing Railway Bureau.It is proved that the location accuracy of the fault location device of 10 kV automatic blocking and continuous transmission lines have reached the engineering requirements and have a certain application prospect.