Research And Software Realization Of Power Supply Simulation For AC Traction Networks

Electric railway in China is developing rapidly,especially the high-speed railway,also,the length of electric railway in service is increasing.Traction power supply system,as an important part of electric railway,it's reasonable design is the key to efficient and stable operation of railway.With the development of computer technology,there have been applications of computer to the calculation and simulation of traction power supply system,but the graphical modeling simulation method has not been employed effectively,moreover,most of these applications are aimed at a supply arm or a power supply zone.Therefore,based on the foundation of predecessors,further researches on the simulation method of coupling two power supply zones and considering the power transfer of two supply arms,and developing the graphical modeling simulation software combined with train traction calculation software,are still of practical significance in the vigorous development of electric railway.In the research of power supply simulation,the paper introduces the basic composition and working principle of traction power supply system firstly,and then analyzes the equivalent model and nodal admittance matrix of each component,especially the multi-conductor transmission line,which is a key component of traction networks.For the convenience of later calculation,the model of multi-conductor transmission line is simplified according to the principle of wire merger and elimination.The mathematical model of traction power supply system is formed by unified chain network model of traction network,model of transformer and power source model of train.Moreover,calculation method of power flow is designed,which lays a foundation for the development of power supply simulation software.In the Development of graphical modeling simulation software,the simulation software is realized based on Visual Studio platform and C#language.The modularization idea is adopted to divide the software into four functional modules,and each module is designed and encapsulated independently.For each component of traction power supply system,class design is carried out.Attributes of each component class(figure attributes,electrical attributes)and methods correspond to parameters and functions of components.A data interface with traction calculation software is designed,which is convenient to load the traction calculation results into the power supply calculation software,and do not need to manually run the train one by one,improving the efficiency of simulation.Taking full consideration of the operation scene,data interface endows users with the privilege of interfering with the interactive process in real time,increasing the practicability of software.For the convenience of later data processing,simulation results are presented and saved in table and graphical format.Last,the effectiveness of the simulation results is verified by an example.Then,with the help of the power supply simulation software,the network model of two coupling power supply zones and the network model of considering power transmission between two supply arms are studied.The former achieves the joint simulation of two power supply zones through the series impedance matrix in the end of a power supply zone,and the later realizes the dynamic balance of two supply arms through power transmission.They are beneficial to improve the voltage distribution in traction network and the utilization ratio of transformer winding capacity.