Research On Traveling-wave Fault Positioning Device For Railway Continuous Power Lines Based On FPGA

To realize the great rejuvenation of the Chinese nation and the strategy of strengthening the country,we need a modern electrified railway transportation system which is green and efficient.Railway Continuous Power Lines is a special power distribution system which provides electric energy for traffic control and station operation.It is easy to occur in the work of difficult to troubleshoot the line fault.The special circuit structure is suitable for fault determination and fault location by using transient traveling wave.The FPGA microcontrol system is suitable for ultra-high speed traveling wave acquisition and real-time analysis.Therefore,it is of great significance to develop a traveling wave fault location device for power transmission line by using FPGA to strengthen the operation safety of electrified railway.Firstly,a fault identification and location algorithm based on transient traveling wave is proposed for the special line structure of power transmission line and the excellent performance of traveling wave location.Based on the theoretical analysis of traveling wave fault location principle and fault signal feature extraction mechanism,the wavelet transform mode maximum algorithm is used to extract characteristic information of transient traveling wave.The fault distance of the line is calculated by the sectional method of modulus wave velocity difference.The simulation model of power through-line was established by using simulation tool MATLAB/Simulink.The influence of fault type transition resistance on fault traveling wave is simulated and analyzed,and the validity of fault location algorithm is verified.Secondly,a traveling wave fault location system for railway power network is established based on AD9238,Xilinx FPGA and AN8211.The lower computer of the system is responsible for the real-time acquisition,storage and transmission of transient traveling wave signals,and Lab VIEW FPGA technology is completely used for the realization of each functional module.The upper computer communicates with the lower computer through gigabit Ethernet.The hardware system of the upper computer is embedded industrial computer.The software system is all developed by Lab VIEW,the function is system control fault analysis and man-machine interaction.In addition,the AD module of multi-chip cascading and synchronous cyclic sampling and FIFO of connecting and feedback between modules are designed to improve the integration and flexibility of the system.Finally,the short-circuit test system of railway through line is built in the laboratory.The traveling wave fault location device is used to capture the transient traveling wave accurately,and the propagation time of the traveling wave is recorded accurately,and the fault properties and fault locations are timely found on the interface of the upper computer.A large number of experiments show that the fault traveling wave location device developed not only has the features of rich functions,friendly interface and convenient operation,but also has the advantages of accurate fault identification and high accuracy.