Design And Simulate Of The Stray Current Experimental System Of The Urban Rail Transit

Currently, in order to develop the economy and improve the public transportation of the city, the urban rail transit has became a inseparabe part because of its convenience, not occupying the urban space and it can improve people’s living conditions. DC traction power supply system are used in the urban rail transit system, the overhead catenaries accept the DC, the locomotive will get the power though the pantograph,then the current flow back into the substation negative busbar by the rail. There will be a problem that can not be absolute insulation between the rail and the earth,a part of current will leak to the earth by this procces which is called stray current, thus lead to the rails along and near metal structures subjecteed the electrochemical corrosion,which resulting in reduce the strength of concrete structure, the useful life of the equipment or threaten the safety of the railway operation, all of thoes questions may cause huge economic losses. It is great significance to research the stray current because of the serious harm caused by it. This article will use this as the background, building stray current experimental system and expand the stray current study under laboratory conditions.This thesis are mainly stated by several aspects:1、In order to explore the damages of corrosion to the surrounding metal structure which is caused by stray current,firstly this paper has analyzed the principle of metal corrosion and then the mechanism of stray current corrosion,the corrosion rate and the basis for judging corrosion will be studied according to the principle. Meanwhile combined the domestic and international perations of the urban rail way to summarize the damages of the stray current.2、By building a model of the stray current experimental system, it was discussed from the unilateral and bilateral two power supply the’rails-the earth’,’the rail-buried metal structures-the earth’,’the rails-drainage net-buried metal structure-the earth’for a total of6model analysis. And comparing the simulation wavform in the unilateral and bilateral power supply which will be find the result is basically the same.For the purpose of building stray current experimental system,a rlatively simple modle can be chosen.Meanwhile the factors of affecting the distribution of stray current are analysised according the calculation model which provide a theoretical basis for the stray current corrosion protection.3、The stray current experimental platform which is based on the MATLAB graphical user interface and the stray current projection teaching platform has been builded.The theory for teaching of stray current experimental system will be demonstrated though the the stray current projection teaching platform.Furthermore,though the two platform,in order to demonstrate the stray current of distribution waveform and the stray current protection measures,take the ’rails-the earth’ model as an example,and demo the protection measures of the stray current in by the projection teaching platform.