Study On Optimization Design Of Urban Rail Transit Cophase Power Supply System

DC power supply mode is adopted in most of the urban rail transit,but there exists the defects of low power supply voltage,large traction network loss,difficulty of making regenerative braking energy give back to the power grid,stray current protrusion and so on.AC power supply mode has the advantages of strong power supply capacity and high power supply efficiency,but there are also power quality problems caused by negative sequence and excessive train phase problems.If cophase power supply technology is applied to the traction power supply system of urban rail transit,it can better meet the technical requirements of urban rail traction power supply.This paper mainly aims at the optimization design of the urban rail power supply system by using the cophase supply technology,and the capacity optimization allocation method of the main power supply equipment is put forward,which provides important theoretical basis and technical support for the efficient,safe and high quality operation of the supply system.As the foundation of traction power supply system design,train traction calculation is an important part of traction supply simulation.The optimization of train energy-saving operation on the basis of conventional traction calculation is studied.The optimization model of train energy saving operation based on spatial state conversion is established.Using genetic algorithm to search for optimal energy-saving running track of train,the energy-saving optimization operation of the train under the condition of given running time is realized.Secondly,the equivalent model of Davidnan of the main substation of the cophase power supply device is deduced.On this basis,the simulation model of traction power supply of the cophase supply system based on the theory of multi-conductor transmission line is established,which provides a simulation platform for the optimal design of supply system.In order to considering both the reliability and economy of the cophase power supply system,an optimal allocation method of the capacity of the cophase supply device constrained by reliability is proposed.Finally,taking the actual route of an urban rail transit as an example,the calculation results of the traction of the urban rail transit train are given,and the traction network impedance and admittance parameters under different sections are calculated.Based on the simulation results,the load capacity of the traction network is verified,and the capacity configuration of the traction transformer and the cophase power supply device is optimized.The economy of the cophase power supply scheme and the original power supply scheme is compared and analyzed,which shows the cophase power supply scheme has advantages in construction investment and operation benefit and has a great application prospect.