Modeling And Optimization Of AC Traction Power Supply System Of Urban Rail Transit

At present,most of the traction power supply systems of urban public transport in China adopt DC system.The advantage is that there is no phase separation and no power free zone,while the disadvantage is that stray current will cause electrochemical corrosion to other metal structures near rails.In addition,due to the relatively low voltage level of DC power supply system,a large number of traction substations need to be installed in the interval to extend the power supply radius,which leads to complex power supply structure,large investment in power supply equipment and related civil engineering.The application of AC traction power supply technology in Metro and light rail can avoid the above problems caused by the existing DC traction power supply system and improve the power supply capacity of the system.this paper makes further theoretical calculation and optimization design for AC traction power supply technology of urban rail transit to provide technical support for its application in actual line.Firstly,the specific structure of the AC traction power supply system of urban rail transit is given,the requirements of each component of the system is discussed,including the calculation of the capacity of the compensation device and the determination of the voltage level of the catenary.In order to improve the reliability of the system,the standby scheme of the system is discussed.Secondly,based on the above-mentioned power supply system topology structure,the parameter matrix of 35 k V Cable is studied.According to the multi-conductor transmission-line theory,the equivalent model of cable traction network is established,the unit impedance matrix and unit admittance matrix of the system are given,the general power supply analysis program is compiled,the power flow distribution characteristics of the system are analyzed and the power supply capacity of the system is discussed.Furthermore,considering the interaction between train and network,a comprehensive energy-saving optimization model is constructed based on the line parameters and train motion equation under the given requirements of transportation organization.Taking minimizing total energy consumption of the system under the interaction between train and network as the goal,the optimization of train on time operation is studied to make full use of regenerative braking energy,so as to reduce the operation cost.Finally,taking the existing line as an example,based on the hybrid genetic particle swarm optimization algorithm,the comprehensive energy-saving optimization design scheme of the urban rail transit AC power supply system project is solved,including the optimized train timetable and operation trajectory.Compared with the original method,the comprehensive model can further reduce the total energy consumption of the system by12.81%,which provides an important support for the energy-saving operation of the urban rail AC power supply system.