Discussion On The Industrial Frequency Single-phase AC Traction Power Supply Sysem Of Urban Rail Transit Power Supply

At present,the domestic trunk railway lines generally make labor frequency system of single-phase AC power supply,urban rail transit traction power supply system usually adopts low voltage DC power supply system,but the adoption of DC system will produce stray current corrosion of underground metal pipelines serious,combined with the current cost of protective measures,the effect is not outstanding,may cause serious consequences.For stray current in principle about eliminate the leakage current,but in practice it is almost impossible.Single-phase AC power supply system and power frequency does not produce similar fan flow under DC power supply system of electrochemical reaction,catenary voltage rating is high,the power supply capability is strong,long number less traction substation spacing,so the research of urban rail transit by power frequency system of single-phase AC power supply is necessary.The way of power supply using 35 kV cable adopts appropriate catenary voltage grade.This paper puts forward negative sequence and reactive power compensation scheme,and the eradication of dc stray current and its bad influence.In this paper,two kinds of single-phase AC power supply system,power frequency of centralized and decentralized respectively.Centralized refers to the traction power supply and dynamic lighting power supply are independent of each other,respectively,two independent systems;Decentralized refers to the shared 35 kV three-phase cable traction and dynamic lighting,influence each other,not separate.Thus to put forward the corresponding compensation according to different ways of power supply scheme,two kinds of compensation packages are the single-phase power supply device combined with phase.For centralized,in the main substation of cophase traction power supply of the negative sequence compensation device for locomotive concentrated compensation,due to the adoption of locomotive is rectangular locomotive,power factor is 0.98～1,has reached the national standard requirements,no longer for reactive power compensation of locomotive parts.For reactive power caused by the dynamic lighting,in the installation of SVC on the low voltage side of the three-phase power transformer by reactive power compensation device,concentrated compensation of reactive power.For decentralized,installed in each of the traction substation in phase compensation device,which compensates for the negative sequence to a locomotive,single-phase electric power load in the dynamic lighting must be considered to cause the negative sequence;For reactive power from power lighting also compensate the phase compensation device,as a result of the reactive power compensation is in 35 kV/400V side,and the electric energy metering points in 110 kV(or 220 kV)high side,so want to consider the situation of reactive power delivers the cable.Then two kinds of compensation packages for theory and economic comparison.First compares the centralized power frequency single-phase AC power supply scheme and the existing DC power supply system of investment,and then compared the centralized AC power supply compensation scheme and a distributed communication power supply compensation plan,based on the actual line contrast the compensation capacity and increase or decrease investment of the equipment.Finally combining with theory and economy adopt centralized power frequency single-phase AC power supply solutions and the corresponding compensation better conclusions.