电气化铁道用单相IGBT-SVG系统构成及仿真研究

电力机车运行对电网造成的污染一直是影响我国电气化铁道发展的因素之一 ,结合国内电气化铁道改造的需要 ,提出了适合电气化铁道用单相IGBT_SVG的系统构成及其控制方法 ,并对给出的系统应用MATLAB软件做了仿真研究 ,仿真结果验证了该方案的可行性     

地方铁路和企业铁路牵引动力的转型

分析了地方铁路企业在牵引动力改造过程中遇到的问题和困难,并提出了建议。     

Interaction between continuous welded rail and long-span steel truss arch bridge of a high-speed railway under seismic action

Track–bridge interaction under the seismic excitation is a dominant factor to the design and operation of railway bridges. A spatial model integrating rails, deck system, stringers, cross beams, suspenders, main trusses, piers and foundations was established in this paper, adopting non-linear springs to simulate the longitudinal resistance between the track and the bridge. The improved Penzien model was utilised to simulate the soil-pile interaction effect and a computer program was developed to generate artificial seismic waves. Comparison of natural vibration characteristics for the track–bridge system with and without considering the track constraint was made. Furthermore, the effects of sensitive parameters were investigated, including the ballast resistance, friction of movable bearings, location of rail expansion joint (REJ), etc. Present study results indicate that the track–bridge interaction enhances the structural integrity and induces relatively higher natural frequencies of the bridge. In general, the response obtained by the ballast resistance specified in the Chinese code is smaller than that by UIC code. Neglecting the friction of movable bearing will lead to over-estimated rail stresses and under-estimated internal forces of some piers in the system. Setting REJ at both beam ends is more efficient to release the seismic stress of the rail on the bridge.     

铁路企业节能统计工作研究

通过对铁路企业节能统计工作＂十一五＂期间所取得的成绩分析,查找目前还存在基础工作不扎实、考核体系不规范、信息服务不到位等问题和不足,提出,从夯实节能统计工作基础、狠抓节能统计数据卡控、完善节能统计考核体系、加强节能统计监测和分析、提高节能统计人员素质5方面加强节能统计管理,为铁路节能减排提供数据保障的建议。     

电气化铁路三相电压不平衡分析算法研究

通过对牵引供电系统结构的分析,推导了三相-两相系统变换方法,将牵引供电系统的两相参数转换为三相系统参数,使牵引供电系统与三相电力系统在拓扑结构上统一起来,从而可以分析牵引负荷引起的电网三相电压不平衡。该算法能够在计算中考虑牵引变压器自身阻抗的影响。使用PSCAD软件与本算法进行了验证,证明了本算法的正确性。     

Vergleich und Beurteilung unterschiedlicher Lastmodelle für die Ermittlung der dynamischen Antwort von Zugüberfahrten über Brücken bei Hochgeschwindigkeitsverkehr

Drei analytische Lastmodelle für die Berechnung von Zugüberfahrten über Brücken werden mathematisch formuliert: eine Folge von Einzelkräften, eine Folge von Punkmassen und eine Folge von Mehrkörpersystemen. Die Kopplung der Lastmodelle an das Brückenmodell erfolgt mechanisch exakt im Rahmen einer ebenen Betrachtung des Problems. Die Diskretisierung der Bewegungsgleichungen erfolgt mit Hilfe der Methode von Ritz und Galerkin (Modalanalyse). Am Beispiel einer leichten Balkenbrücke aus Stahl unter der Einwirkung eines Hochgeschwindigkeitszuges werden die drei Lastmodelle untereinander verglichen. An diesem Beispiel wird deutlich, dass mit Lastmodellen aus Einzelkräften oder Punktmassen die Schwingungsantwort von leichten Brücken stark überschätzt werden kann. Bereits die Verwendung von einfachen Mehrkörpersystemen mit nur wenigen Freiheitsgraden führt zu wesentlich genaueren Ergebnissen, insbesondere bei resonanzgefährdeten Brücken. Wege für eine effiziente Berechnung stehen unter Anwendung der Modalanalyse offen und werden ebenso diskutiert wie die Beurteilung der Resonanzgefahr. Comparison and assessment of various load models to calculate train crossings of bridges at high speed. Three analytical load models to calculate train crossings over bridges are mathematically formulated: a series of concentrated forces, a series of concentrated masses and a series of multi‐body systems. The coupling of the load models to the bridge model is carried out within the scope of a two‐dimensional treatment of the problem and without simplifications. The differential equations of motion are discretised using the method of Ritz and Galerkin (modal analysis). The three load models are compared with each other using the example of a lightweight beam bridge made of steel which is loaded by a high‐speed train. The example shows clearly that the dynamic response of a lightweight bridge is overestimated if the load models consist of concentrated forces or masses. Even the use of simple multi‐body systems with only few degrees of freedom lead to considerably more accurate results. This finding particularly holds true for bridges which are at risk of resonance effects. Options for an efficient calculation are available with modal analysis and are discussed. The assessment of resonance effects is also treated.     

高铁接入网切换问题理论分析(英文)

To handle the handover challenge in Express Train Access Networks(ETAN).mobility fading effects in high speed railway environments should be addressed first.Based on the investigation of fading effects in this paper,we obtain two theoretical bounds:HOTiming upper bound and HO-Margin lower bound,which are helpful guidelines to study the handover challenge today and in the future.Then,we apply them to analyze performance of conventional handover technologies and our proposal in ETAN.This follow-up theory analyses and simulation experiment results demonstrate that the proposed handover solution can minimize handover time up to 4ms(which is the fastest one so far),and reduce HO-Margin to 0.16 dB at a train speed of 350km/h.     

矿区铁路中机车运用的探讨

分析矿区铁路运输现状和机车运用方面存在的问题,提出了从机车运用组织形式,作业区域划分,调车组的合理安排,现场作业标准,设备更新和加大职工培训等方面改善机车运用方式,实现机车有效运用。     

铁路既有线顶进施工线路加固总结

针对铁路既有线桥涵改造加固的主要难点及风险,结合现场施工环境,选择了不同的线路加固方案,对不同的施工方案进行了比较分析,从而得出最优方案,使线路加固方案更加科学、可靠.     

Electrotribological property of the Cu−Ag−Cr alloy with high-strength and high-conductivity

By means of a vacuum induction furnace, a Cu−Ag−Cr alloy was produced. The electrotribological property and mechanism of the Cu−Ag−Cr alloy wear studied via wear property tests, scanning electron microscope (SEM), energy dispersive X-ray spectrum (EDS) and transmission electron microscopy (TEM). Wear tests were conducted with a specially designed sliding wear tester, which simulated the tribological conditions of sliding current collectors on contact wires in a railway system. The alloy wire was slid against a copperbased powder metallurgy strip under non-lubricated conditions. The results showed that the wear rate of Cu−Ag−Cr alloy increases as the sliding speed increases under a normal load. Adhesive wear, abrasive wear, and electrical erosion wear are the governing wear mechanisms under the electrical current sliding processes. Under the same conditions, the wear resistance of the Cu−Ag−Cr alloy is 2–3 times that of the Cu−Ag alloy.