Research On The Harm And Treatment Of Stray Current In Urban Rail Transit

Currently,DC traction power supply is widely used in subway systems.Using the sliding contact between the overhead contact net(contact rail)and the pantograph(collector),the subway train can obtain the required electrical energy.Since the current is returned to the traction substation by the running rail and the running rail as a return conductor cannot be completely insulated from the ground,which will cause a small portion of the return current to leak to the ground.This part of the leakage current is called stray current.Because of its existence,the underground metal structure pipes and lines will be seriously corroded,thus affecting the normal operation of the subway.Therefore,this thesis has carried out in-depth research on the problem of stray current in subway and proposed a series of protective measures to ensure the safety,stability and reliability of subway operation.The research targeted in this thesis mainly includes the following parts:1.For the stray current of the subway,the mechanism of its generation is fundamentally studied and its characteristics are further analyzed to provide guidance for subsequent protection.2.Because the stray current will cause corrosion damage to the subway system,the corrosion mechanism of stray current is revealed and the electrochemical process involved is analyzed.The actual damage caused by stray current is further explained in combination with the subway operation site..3.Due to the presence of stray currents,the screen doors will generate voltage differences correspondingly,which seriously threatens the safety of passengers.Therefore,the research is carried out for the special system of screened door and the measurement of the voltage difference of the screen door and the insulation level are introduced in detail.Finally,the specific solutions for the influence of stray current on the screen door are given.4.The treatment of subway stray current is a systematic project,which not only needs to be fully considered at the beginning of design,but also takes corresponding measures to prevent the corrosion of stray current in the process of construction and operation.Therefore,in view of the subway system,this paper proposes a series of comprehensive prevention and control measures,namely,“mainly based on prevention,supplemented by row,combined with prevention and control,enhanced monitoring” and a variety of special protective measures.Figure: 38,Table: 13 References: 47...