Research On Voltage Compensation Scheme And Capacity Configuration Optimization Of Cable-only High-voltage Power Line Along The Railway

As one part of the E&M system,railway power supply system has extreme significance for railway operation safety.In order to ensure the reliability of power supply system of railway,cable-only power line along the railway is laid in high-speed railway or the railway with harsh natural environment surrounding.Compared with overhead line,cable-only power line along the railway improves the reliability of power supply but brings capacity effect.In China,the surroundings of railway are much harsher than the lines in Western European countries.In other words,the existing cable-only power lines,there are few theoretical analysis and comparisons between compensation schemes and the capacity allocations,and no unified standards have been formed yet,and the following researchs are carried out in this thesis:(1)The cable type that appropriate for the application of the railway power supply system and the calculation of electrical parameters of cable are presented in this thesis.Based on the factors which affect the cable parameters,the mathematical model of cable-only continuous power transmission line is also established and analyzed in thesis.(2)In order to solve the power quality issues of the cable-only continuous power transmission line,the methods of reactive power compensation for cable-only power line along the railway are summarized by combining the actual situation of railway power supply system in China,including two terminals concentrated compensation,dispersed compensation and head terminal concentrated compensation with dispersed compensation.Meanwhile,cable-only continuous power transmission line could also be divided into three types: short line,long line and medium line by length.Conclusion of simulation analysis could be concluded by comparing and analyzing the simulation which are used to simulate in no load condition.(3)The capacity optimization configuration is carried out for head terminal concentrated compensation +dispersed compensation.The reactive power optimization of distribution network,the load flow calculation method,and the reactive power optimization model are presented in this thesis.Lanxin high-speed railway Yuliu section is taken as an example and the genetic algorithm is used to optimize the reactive power capacity configuration which is compared with the traditional capacity configuration indicate that on the premise of guaranteeing power quality,the compensation capacity is reduced by 55%,.(4)The selection for dynamic reactive power compensation equipment of the head terminal concentrated compensation with dispersed compensation is studied in this thesis.Diffirent kinds of dynamic reactive power compensation equipments are contrasted and analysed in this thesis.Base on the actual condition of railway power supply system,activecompensation device SVG is intended to use and compared with the packet switching reactor whose compensation effect are analyzed by Matlab/Simulink simulation model which could prove the feasibility of the SVG compensation way.