Study On Optimization Design Of Cophase Continuous Traction Power Supply System

With the development of electrified railway aims at high speed and heavy load,the power quality problems of traction power supply system include negative sequence,harmonic,reactive power.Cophase traction power supply technology is the best integrated solution for power quality problems which can remove the electrical separation at the substation terminal.It has the functions of filtering harmonics,reducing negative-sequence components and compensating reactive power.Combined cophase traction power supply system is improved on the basis of the cophase traction power supply system.The traction power supply system and negative sequence compensation is separated in structure and combined with each other in function.It is able to achive optimal design of compensation devices with least capacity and best technology and economy in the limit of electric energy quality standard.And it's necessary to research the design of combined cophase traction power supply system with mature technology and development of engineer.In this dissertation,an optimized design scheme of the cophase continuous traction power supply system about the selection of location and capacity of power supply facilities is studied through the computer simulation techniques and artificial intelligence algorithms.At the same time,the economic of different power supply programs is analysed.First of all,the structure and principle of cophase traction power supply system are introduced.Next,the traction and power flow simulation model is set up and analyzed.Based on the simulation of a certain line the power supply capacity and maxinun demand are compared between the traditional traction power supply system and the cophase traction power supply system.It can demonstrate the advantages of the cophase traction power supply system.Then,the basic principle of the particle swarm optimization(PSO)algorithm is briefed.The multi-objective particle swarm optimization(MOPSO)based on Pareto entropy is studied and the functions are test.At the same time,the optimized design model of cophase traction power supply system is established by modified PSO algorithm.At last,the cophase traction power supply system is modified under the limit of voltage which can be 22.5kV or 20kV.The optimal program is choosen by total cost and the capacity of traction substation and compensation device is fixed by optimized compensation.Then technical index and economic benefit are analyzed and compared for non-cophase continuous,cophase continuous and the optimal cophase continous traction power supply system.Above all,it can be proved that the optimal cophase continuous traction power supply system can improve economy further.