Train Locomotive Harmonic Current Measurement And Research Of The Electromagnetic Compatibility Assessment

With the rapid development of economy in China, the demand for high-speed transport capacity is increasing. The high-speed railway is marching in the stage of full development. With A-D-A locomotive widely used in the high-speed railway, harmonic problems generated by the AC drive system have become increasingly prominent which seriously affects the safety and normal operations of railway. On the one hand, if the frequency of traction return harmonic falls into the bandwidth of track circuit signal, it will seriously affect the normal operation of track circuit system; On the other hand, harmonic currents that electric locomotive injects into the traction network will result in resonance under certain conditions, and the over current or voltage will cause the traction power supply system failure which leads to the train outage. Therefore, solving the harmonic current problem of AC drive system has become one of the technical problems needed to solve in the high-speed railway.The thesis briefly discussed the basic structure of traction power supply system based on interferences, and detailed the compatibility issues between railway rolling stock and track circuit. On the basis of the standard, CLC/TS50238-2Railway Applicatons-Compatibility between rolling stock and train detection systems-Part2: Compatibility with track circuits, the paper introduced the interference current limits and data processing methods for the ZPW-2000and FTGS46/917track circuit. Then, the author concretely described the hardware and software implementation of the harmonic current automatic measurement system, and did some functional verifications. The result proved that the automatic test system could work stably. The test data also was accurate and reliable. Finally, the author measured the traction current data using this system on a high-speed railway. By analyzing the data, the author got the compatibility conclusion between locomotive and track circuit, the distribution of main traction harmonic current and the regulations between main traction harmonic current and train operating conditions.For the problem of traction network resonance, the thesis gave a first discussion of the distributed parameter transmission line theory and two-port equivalent π-type model. Further on multi-conductor transmission line system, the paper converted the multi-conductor transmission line to a single-phase transmission line based on the eigenvalues of matrix decomposition idea, and given the general closed solution of voltage and current by known the terminal voltage and current conditions through theoretical analysis. Then by using the impedance and admittance reduction method in the reduced model of multi-conductor transmission system, the traction network multi-conductor transmission line system was equivalent to single-phase transmission line equivalent π-type model to study. The author established traction network resonance simulation model in Matlab simulation software, including traction network equivalent model, electric locomotive equivalent model, traction substation equivalent model, and researched the traction network resonance mechanism and influence factors. The author also explained the traction network resonance phenomenon during the train operation based on the simulation results. Compared to the measured data of traction current, it turned out that the simulation results were correct. Finally the paper pointed out some effective methods to suppress resonance according to the simulation results.