| With the continuous development of high-speed and heavy-duty railroads,electromagnetic interference has become more and more serious,and the immunity performance of railroad signal equipment has become an important indicator of safety and reliability.To ensure the normal operation of railroad signal equipment in the field electromagnetic environment interference,the immunity test of railroad signal equipment in the traction current immunity test platform is very necessary.The current traction current immunity test platform signal occurrence has many shortcomings: the use of existing signal equipment through manual control,low efficiency and not accurate enough;test results only have two conclusions whether to pass,the lack of specific quantitative evaluation of the signal quality of the equipment under test analysis;does not take into account the equipment under test signal to test equipment energy coupling,affecting the accuracy of the test.In this paper,according to the national railway group enterprise standard "Q/CR 628.1-2017 railroad signal equipment traction current immunity test method Part 1: track circuit equipment" and "Q/CR 628.2-2018 railroad signal equipment traction current immunity test method Part2: on-board track circuit information receiving equipment" and other related standards,on the basis of virtual instruments,around the traction On the basis of virtual instrumentation,research is conducted on signal generation and processing in the traction current immunity test platform,coupling analysis of each system and design verification of decoupling schemes.1.Based on the traction current immunity test platform architecture,analyze the interference mechanism of unbalanced traction current on railroad signal equipment,complete the overall design of signal generation system according to Q/CR 628.1-2017,Q/CR628.2-2018 and TB/T3073,and determine the main technical indicators.Specify the signal current,amplitude and power of each system track circuit;analyze the coupling relationship between test equipment and tested equipment as well as system interference circuit and signal circuit under the test conditions of insulated track and uninsulated section track.2.Based on the Lab VIEW development environment,the software design for signal generation and analysis of the rail circuit is completed.The overall software design is "two-way and three-step",with the signal generation module and signal processing module as the two-way and the three-step as the top application,the background code logic specification and the underlying system driver.The signal generation module and processing module run in parallel,which can complete the required signal generation and multi-dimensional analysis of the collected signal in the time domain and frequency domain,using wavelet transform technology and combined with Mallat algorithm to accurately capture signal distortion points.3.According to the analysis of the coupling of each circuit inside the test platform,the hardware decoupling design is proposed for the industrial frequency interference,and the software decoupling design based on virtual instrumentation is implemented for the interference frequency band close to the signal frequency band to ensure the accuracy and authority of the results as a test system.Hardware decoupling is verified by combining Multisim simulation and actual test data in the field;software decoupling uses windowed interpolation FFT method to transform the signal,realize interference spectrum extraction and signal compensation,and use IIR filter to filter and reduce noise from environmental noise and other electrical equipment secondary noise in the field to improve signal-tonoise ratio.Simulation and field application verification show that the method used in the thesis has strong applicability.It is able to generate and make the test platform operate accurately for each system signal of the track circuit according to the standard requirements;it has significant decoupling and filtering effects on specific aspects of the system,improves the test accuracy,provides a reference for railroad signal traction current immunity testing,and has strong engineering application value. |
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