Research On Electromagnetic Transient Process Of Electric Locomotive System

ABSTRACT: Locomotive is one of the key equipments in railway transport. Locomotive often undergo different transient processes when it change its operation states. Intensive electromagnetic transient process will lead to high-amplitude impulse voltage or current which will deduce the thyristor arcing and capacitance destroy. Over-voltage will also occurred in the fist side of transformer because of the coupling which can deduce arrester discharging and insulation arcing. Locomotive can not run because of the tripping in electric power substation. It influences the normal transport seriously. Study on the different transient processes supply the theory foundation to resolve the practical problem and guarantee the safety running of locomotive.Magnetization curve is the basis of modeling the traction motors correctly. Make SS series AC-DC Locomotive as instance build dynamic model of locomotive. The dissertation presents bayesian least squares support vector machine (LS-SVM) as a new tool fitting magnetization curve which can solve the problem of time-consuming that traditional LS-SVM model parameters determined by cross validation. The dissertation analyzes the two-level SPWM and three-level SPWM separately and build the dynamic model of CRH1 and CRH2.Considering the pulsating current in the thyristor driven dc motor, transient process of abnormal operation and failure of regenerative braking is modeled and analyzed. Mathematic expressions on transient process of the abnormal operation and failure of regenerative braking are deduced. Making SS7 as an example, compute the transient process of abnormal operation and failure of regenerative braking. Using the dynamic simulation model simulate the two transient processes. Experiment was done to verify the analysis and simulation.The process of locomotive slipping through articulated phase insulator can be divided in three transient processes. The transient voltage on articulated phase insulator and inrush current are deduced and calculated using electromagnetic transient mathematic method. Field survey verifies the correctness of theory analysis and simulation.Modal analysis is proposed to study the characteristic root of the network admittance matrix. Using this method, one can find the relationship between harmonic resonance of traction system and frequency and locomotive position. Analytical and case study have confirmed that the proposed method is a valuable tool for traction power system with moving load.Through the study on typical transient processes, the reasons how the intensive electromagnetic transient process will occur are found out. Analyze the over-current and over-voltage influence on the locomotive and traction system. It supplies the theory support to the safety running and system design.