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Friction 2024年第4期12卷 796-811页

作者： Samuel BOND Robert L.JACKSON German MILLS Department of Chemistry and Biochemistry Auburn UniversityAuburn 36849-5412USA Department of Mechanical Engineering Auburn UniversityAuburn 36849-5412USA

Leakage currents accelerate surface degradation of metal contacts via small scale arcing across lubricating films,but recent observations suggest that metallic nanoparticle additives in lubricants may be useful to improve contact performance.These findings prompted a study that examined electrically induced surface pitting of steel contacts in the presence of several lubricating greases including some containing nanometer-sized colloidal silver(Ag)particles.Reciprocating rolling sphere-on-disk experiments were conducted under electro-tribological loads employing polyurea greases derived from mineral and synthetic base oils with and without additives.Friction forces and electrical resistance were monitored continuously during the tests;surface changes were characterized by means of optical spectroscopy,stylus profilometry,and scanning electron microscopy(SEM)including compositional analysis using energy dispersive spectroscopy(EDS).The observations demonstrate that surface pitting induced by arcing occurs mainly at the points were the rolling motion changes direction and that eroded metal is deposited along the wear grove.Micron-sized pits are formed which contain carbon and oxygen indicating that arcing causes decomposition of the hydrocarbon lubricants.Numerous findings indicate a significant inhibition of pitting is induced by the Ag nanoparticles;some greases containing other additives exhibit a similar,although less pronounced,effect.

关键词： electric motor bearings wheel bearings electric vehicles arcing electrically induced bearing damage pitting leakage current stray current

Integration of PV and Battery Storage for Catenary Voltage Regulation and stray current Mitigation in MVDC Railways

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Journal of Modern Power Systems and Clean Energy 2021年第3期9卷 585-594页

作者： Salman Aatif Xiaowei Yang Hai Hu Santa Kumar Maharjan Zhengyou He the School of Electrical Engineering Southwest Jiaotong UniversityChengduChina the Department of Electrical Engineering(Bannu Campus) University of Engineering&Technology(UET)PeshawarPakistan

Innovative advancement in power electronics is reshaping the conventional high-voltage transmission systems and has also opened a new paradigm for researchers to consider its benefits in the railway electrification system(RES).In this regard,the medium-voltage direct current RES(MVDC-RES)is a key area of interest nowadays.In this paper,a secondary energy source(SES)consisting of renewable energies(REs)and energy storage systems(ESSs)is proposed to solve the issues of catenary voltage regulation,rail potential,and stray current in the MVDC-RES.Some of the major integration topologies of the SES are analyzed for MVDC-RES and the most effective one is proposed and implemented.The voltage at the point of connection(PoC)of the SES is used as a reference for controlling different operation modes of REs and ESSs.Moreover,feedforward control is used at the ESS converter to attain the quick response from the batteries for the desired operation.The proposed scheme improves the catenary voltage,and reduces the rail potential and stray current.Besides,the scheme provides higher energy density and reduces line losses.Simulation results are provided to validate the operation modes and advantages of the proposed scheme.

关键词： Medium-voltage direct current(MVDC)railway railway electrification system(RES) catenary voltage regulation stray current photovoltaic(PV) energy storage

Analysis of rail potential and stray current in MVDC railway electrification system

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Railway Engineering Science 2021年第4期29卷 394-407页

作者： Salman Aatif Haitao Hu Fezan Rafiq Zhengyou He School of Electrical Engineering Southwest Jiaotong UniversityChengdu 610031China Department of Electrical Engineering(Bannu Campus) University of Engineering and Technology PeshawarPeshawarPakistan Department of Electrical Engineering NED University of Engineering and Technology KarachiKarachiPakistan

In contrast to the conventional direct current railway electrification system(DC-RES),the medium voltage direct current(MVDC)-RES is considered promising for long-distance high-speed corridors.In the MVDC-RES,traction substations(TSSs)are placed much farther and train loads are much heavier than in the conventional DC-RES.Hence,the MVDC-RES brings a drastic change in catenary voltage,TSS spacing,and train loading,which affects rail potential and stray current.In this connection,this work performs some significant quantitative analysis of rail potential and stray current in the MVDC-RES environment.An MVDC simulation model is proposed and different grounding schemes are analyzed for a single-train and two TSSs scenario as well as for a multi-train multi-TSS scenario.According to the simulation and analysis,the maximum values of rail potential and stray current at MVDC-RES distances and the maximum safe distance between adjacent TSSs are determined.

关键词： Railway electrification Medium voltage direct current(MVDC)railways Rail potential stray current stray corrosion

Simulation Experiment of Loading Influence to Reinforcement Corrosion Affected by stray current and Salt Solution

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武汉理工大学学报 2010年第17期32卷 147-151页

作者： TENG H W YANG S M SHU Z C HUANG Y HUO D College of Architecture and Civil Engineering Beijing University of TechnologyBeijing 100124China Beijing Key Lab of Earthquake Engineering and Structural Retrofit Beijing University of TechnologyBeijing 100124China

According to the service environment of subway structure,experiment is carried out to simulate influence of different loading levels to reinforcement corrosion of R.C element affected by stray current and chlorine salt solution. The current density of the corrosion is measured with the linear polarization resistance method,together with the qualitative analysis and quantitative calculation. Experiment shows that rebar corrosion current density increase accordingly with the increase of loading level. The quantitative relations and the time of rust corrosion of reinforcement are obtained.

关键词： reinforcement corrosion stray current chloride ion solution loading level simulation experiment

The Inspecting Technology of stray current induced by DC Mass Transportation Rail System and Prevention of Corrosion for Underground Pipelines

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The Inspecting Technology of Stray Current induced by DC Mas...

Study on Mechanism of Concrete Failure Induced by Steel Corrosion under Externally Applied Direct current

2010年海峡两岸材料破坏/断裂学术会议暨第十届破坏科...

作者： Guo-Shiu Liu Jeng-Yu Chen Ming-Hung Lin Frank-F.Sheu Refining&Manufacturing Research Center Chinese Petroleum Corporation

Among the types of corrosion for steel material,the attack of stray current is the most strong and focus type and affects public security strictly.When stray current flows into underground pipeline or oil groove directly or through electrolyte and flows back to original line somewhere of metal structure directly or through electrolyte,it occurs to electrochemistry corrosion to metal structure.It leads to consumption of structural steel material and makes leakage of content which arises pollution of environment,fire and even explosion.Public mass rail transportation(MRT)system rectifies 161 kV alternating current supplied by power company into 750 V direct current.After driving tramcars to move by the third rail set on the ground or parallel to steel rail,the traction current flows to steel rail and then back to substation through a grounding brush.Preventing returning current from leaking to ambient surrounding,there must be insulation spacer set below steel rail or even stray current gathering equipment for the secondary defence.However,the current delivered by steel rail set barely on the ground easily flows to underground structure through the contacts between steel rail and the ground and causes electrochemistry corrosion.We can find that the potential interference to underground structure from stray current is getting more and more serious by the inspection of pipeline potential carried out from background value to the period of MRT system commissioning test and then opening to traffic.This article takes potential change more than 100 mV as standard of interference from stray current.However,we can measure high potential change of parts of pipeline up to 2 V after MRT system opening to traffic and the frequency of potential change corresponds to the time of MRT system operation.Thus,the interference to underground structure from stray current came from MRT system is undoubted and severe.The company of MRT system should cooperate with the company of underground pipelines to face the problem of stray current t

关键词： stray current Cathodic Protection

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Journal of Modern Transportation 2001年第1期18卷 25-34页

作者：周晓军高波郭建国 School of Civil Engineering Southwest Jiaotong University Beijing Metro Incorporation

With the combination of electrochemical corrosion due to stray current in running tunnels of metro, the formula to determine the corrosion products of rebars in reinforced concrete subjected to externally applied direct current is proposed, and the influence of corrosion on stress in concrete is also discussed. Meanwhile, the concept of corrosion stress field and its mathematical formula are presented in the paper. Finally the failure mode of concrete and its shortest breaking time are also analyzed.

关键词： reinforced concrete corrosion stray current failure mechanisim corrosion stress field

Modeling and Analysis of Permanent Magnetic Driver with Notched Conductive Plate

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Modeling and Analysis of Permanent Magnetic Driver with Notc...