Simulation Model And Dynamic Power Flow Calculation Of AC Traction Power Supply System

In recent years,with the country’s strong support for the railway industry,our country’s railway sector has developed rapidly.From plain areas to high-altitude areas,connecting provinces and cities to prefectures and counties,our country’s railways have almost achieved full coverage.Based on this,people’s requirements for the safety and stability of the traction power supply system are also increasing.A complete traction power supply system is composed of traction transformers,traction networks,traction loads and other equipment.Among them,the traction network as a transmission medium for powering the locomotive,plays a pivotal role in ensuring the safe and stable operation of the locomotive.Therefore,the establishment of an accurate model of the traction network and more accurate line parameters can lay a reliable data foundation for the calculation of the power flow of the traction network.In this thesis,the Autotransformer(AT)power supply traction network is the research object,and the simulation model of the traction power supply system,the traction load model based on the actual line conditions and the power flow calculation of the traction network are built.The specific content is as follows:(1)The complex multi-conductor structure of the traction network is simplified by combining wires.The calculation method of the self-impedance of the conductor after the merger,the self-impedance of the remaining conductors,and the mutual impedance between the remaining conductors and the merged conductor are obtained through circuit theory,which provides accurate electrical parameters for building the traction network simulation model.(2)Two simulation models of traction network are built in MATLAB/Simulink,which are a lumped parameter model and a distributed parameter model.The basic principles of the two models are analyzed,the two traction network models are compared through calculation examples.We can Analyze and obtain the applicable conditions of the two models.(3)Based on the actual operating line conditions of the locomotive,a set of state vectors is proposed to describe the operating state of the locomotive at a certain time,combined with the locomotive operation diagram,to build a model of the locomotive at any time,which can describe more accurately than the constant power model Traction load.(4)The power flow calculation of the traction network is carried out based on the current distribution law of the traction network and the actual operating power of the traction load.The former obtains the analytic formula for calculating the voltage and current at any position of the traction network,which can avoid the calculation of complex impedance matrix and admittance matrix;the latter realizes the calculation of the power flow of the traction network by programming,which has better universality.Finally,the two power flow calculation methods are compared and analyzed.