Research On Test Platform For Railway Signalling Equipment Against Unbalanced Traction Current Interference

With the increase in speed of China’s high-speed railways and the increase in the load capacity of heavy railways,the power of the traction power supply system in the electrified sections of railways is increasing,and the consequent increase in unbalanced traction current cause interference to railway signalling equipment,in this context,the anti-interference ability and reliability of railway signalling equipment is particularly important as the key to ensuring the safety of train traffic.At present,the antiinterference ability of railway signalling equipment against unbalanced traction current is required to be tested in accordance with the China Railway Corporation’s Q/CR 628 standard series "Test Methods for Traction Current Immunity of Railway Signalling Equipment".However,there is currently no automatic test platform to match this standard series.For this reason,this paper carries out the research on the automatic test platform for the unbalanced traction current immunity of railway signalling equipment.The main work of this thesis is as follows.(1)The thesis analysed the interference mechanism of unbalanced traction currents on railway signalling equipment,clarified the various interference modes of traction currents,and on this basis,combined with the requirements of Q/CR 628,conducts a requirements analysis for the design of the test system,clarifies the composition,functions and test solutions for different equipment of the test system.(2)Based on the concept of virtual instrumentation,the thesis designed the hardware part of the test system,including: the selection of PXIe bus,acquisition cards and test instruments according to the requirement analysis to ensure the stability and accuracy of the test system;and designs the interface circuit between each sub-system to achieve the acquisition of various information within the test system and ensure the monitoring of the status of the equipment under test;next,the thesis completes the design of auxiliary equipment such as coupling and decoupling devices in the test system was completed to solve the problem of inaccurate test results caused by the unstable impedance of the test system.At the same time,the electromagnetic compatibility of the test system was analysed,twisted-pair transmission was adopted and a reasonable wiring scheme was proposed,which effectively suppressed the electromagnetic disturbance in the system.(3)Under the Labview software development environment,the thesis completes the software design of the test system.The test software is divided into device driver layer,application execution layer and human-machine interface layer from the bottom to the top layer.The top-level module reuses the code of the bottom-level module by dynamically calling the bottom-level module to realise the functions of data acquisition and real-time display,automatic data storage,hardware control within the test system,report generation,playback analysis and communication with the transmitter through VISA.The fuzzy PID control algorithm is also applied to achieve the closed-loop automatic adjustment of the injected signal and disturbance during the test process.By designing a reasonable fuzzy controller,the self-tuning of the PID parameters during the adjustment process is achieved to improve the speed and accuracy of the adjustment compared to the traditional method.(4)The thesis calculated the measurement uncertainty of the test system based on the Matlab implementation of the adaptive Monte Carlo method,and the error of the test system is analysed and verified to verify that the test system is designed to meet the error range required by the standard.Finally,immunity tests were conducted on track circuit equipment and locomotive signalling equipment by this test system to verify the functionality and efficiency of the whole test system.