(完整版)接触网英文翻译英文毕业设计论文
毕业设计中英文翻译【范本模板】
英文The road (highway)The road is one kind of linear construction used for travel。
It is made of the roadbed，the road surface, the bridge, the culvert and the tunnel. In addition, it also has the crossing of lines, the protective project and the traffic engineering and the route facility。
The roadbed is the base of road surface, road shoulder，side slope, side ditch foundations. It is stone material structure, which is designed according to route's plane position .The roadbed, as the base of travel, must guarantee that it has the enough intensity and the stability that can prevent the water and other natural disaster from corroding.The road surface is the surface of road. It is single or complex structure built with mixture。
The road surface require being smooth，having enough intensity，good stability and anti—slippery function. The quality of road surface directly affects the safe, comfort and the traffic。
毕业设计外文原文+翻译(电力系统)
河南理工大学HENAN POLYTECHNIC UNIVERSITY英文文献翻译En glish literature tran slati on学院：电气工程与自动化学院专业班级：___________ 电气11-4班_______ 姓名： __________________ 宋家鹏_______ 学号：311008001120 __________ 扌旨导老师：____________ 汪旭东_______2014年6月5日河南理工大学HENAN POLYTECHNIC UNIVERSITY2.5 对称三相电路在这一部分，我们介绍三相对称电路的一下几个话题：丫连接,相电压，线电压，线电流，△形连接负荷，△ - Y变换，以及等效的相图。
c Ca Ab B图2-10三相Y连接电源带Y连接对称负荷电路图对称Y连接图2-10显示的是一个三相Y连接电源带Y连接对称负荷电路图。
对于Y连接电路，每个相的中性点是连接起来的。
在图2-10中电源中性点标记的是n,而负载中性点标记的是N。
把三相电源假设为理想电源，即阻抗忽略不计。
同时，电源和负载之间线路阻抗，中性点n与N之间的线路阻抗也可忽略不计。
三相负荷是对称的，意味着三相之中任意两相间的阻抗是相同的。
对称相电压在图2-10中,三相电源的终端呗标记为a、b、c,电源相电压标记为E an ,E bn，E cn，当电源的三相电压有相同的幅度，任意两相之间互差120度角时，电源是对称的。
当以E an 作为参考相量时，相电压的幅值是10V，对称三相相电压如下所示：E an=10 0E bn10 120 10 240 (2.5.1 )E cn10 120 10 240河南理工大学HENAN POLYTECHNIC UNIVERSITY图2-11以E an 作为参考的对称正序相电压向量图当E an 超前E bn 120度，E bn 超前E cn 以120度角时，此时的相序称为正相序或 者abc 相序。
铁路接触网个人技术技能工作总结
铁路接触网个人技术技能工作总结英文回答：Railway Overhead Contact Line Personal Technical Skills Work Summary.In my role as a railway overhead contact line technician, I have developed a range of technical skills that have been instrumental in my job performance. Throughout my career, I have consistently demonstrated proficiency in various areas, including installation, maintenance, and troubleshooting of the overhead contact line systems.Firstly, I have extensive experience in theinstallation of overhead contact lines. This involves setting up the necessary infrastructure, such as masts, cantilevers, and brackets, and ensuring proper alignment and tension of the wires. I am well-versed in the use of specialized tools and equipment required for theinstallation process. Additionally, I have a strong understanding of safety procedures and regulations related to working at heights and working near electrical systems.Secondly, I have a solid background in the maintenance of overhead contact lines. This includes regular inspections to identify any signs of wear, damage, or degradation in the wires, insulators, or other components.I am skilled in conducting routine maintenance activities, such as cleaning, lubricating, and tightening connections.I also have experience in conducting more complex repairs and replacements when necessary. My attention to detail and ability to identify potential issues early on have been key in ensuring the reliability and safety of the contact line system.Furthermore, I have developed strong troubleshooting skills in dealing with issues that may arise in the overhead contact line system. This involves diagnosing problems, such as power supply interruptions, wire breaks, or faulty connections, and implementing appropriate solutions. I am adept at using diagnostic tools andequipment to identify the root cause of the issue and implement effective repairs or adjustments. Additionally, I have experience in coordinating with other teams, such as electrical engineers or signal technicians, to resolve complex problems that may require collaboration.In summary, my work as a railway overhead contact line technician has allowed me to develop a range of technical skills that are crucial to the successful installation, maintenance, and troubleshooting of the contact line system.I am confident in my abilities to handle various tasks related to the overhead contact line and contribute to the smooth operation of the railway infrastructure.中文回答：铁路接触网个人技术技能工作总结。
英文翻译论文(模板)
本科生毕业设计（论文）专业外文翻译原文：Magnesium alloy electric wheel hubmicro-arc oxidation production research译文：镁合金电动车轮毂微弧氧化生产研究指导教师：张清郁职称：讲师学生姓名：陈孟丽学号：1002130301专业：机械设计制造及其自动化院（系）：机电工程学院2015年4月10日Magnesium alloy electric wheel hub micro-arc oxidation production researchMost electric vehicles at home and abr o ad is configured t o aluminum alloy wheel hub,its quality,energy saving,shock absorption,noise reduction and vehicle dynamics characteristics index is much lower than magnesium alloys.Magnesium alloy is30% lighter than aluminum alloy,th e damping effect is30times that of aluminum alloy. Replace the aluminum alloy with magnesium alloy wheel hub,driving the development of magnesium alloy material development and deep processing technology,t o reduce electric vehicle weight and power consumption,energy conservation and environmental protection; T o reduce vibration and noise;Improve ride comfort and electric vehicle dynamic characteristics such as objective(transportation quality each reduce10%,energy consumption will be r educed8%~10%).But its corrosion resistance is poor,seriously limits the monly used chemical oxidation and anode oxidation formation of oxide film on magnesium alloy has certain protective effect,but its corrosion resistance, environmental friendliness,appearance is not satisfactory,be badly in need of the development of new surface treatment.In recent years,people trying to develop a variety of new technologies,such as micro arc oxidation technology,the betterOne Micro-arc oxidation mechanismMicro-arc oxidation technology is a new surface tr eatment technology of gr een environmental protection,can grow in light metal surface in situ ceramic layer directly.Its technological characteristics,surface treatment,as well as the performance of the since the technology was invented by the favour of people,its mechanism is t o light metals such as aluminum,magnesium,titanium and its alloy pu t in electrolyte a q ueous solution as anode, using the method of electrochemical spark discharge spots on the surface of the material, the thermal chemistry,plasma chemistry and electrochemistry,under the joint action of metal oxide ceramic layers of a surface modification technologyTwo research methods and technologyThis topic in the research on magnesium alloy electric wheel hub,higher requirements on the t oughness of the alloy,so choose AM60B,melt and initial temperatur e of468℃,the melting end temperatur e is596℃,the liquidus temperatur e range of 165℃.The chemical composition as shown in table1.T able1AM60B alloy chemical composition(WB/%)Al Zn Mn Si Cu Ni Fe杂质余量5.6～6.4≤0.200.26～0.5≤0.05≤0.008≤0.001≤0.0040.02Mg Because of the magnesium alloy electric wheel hub surface area is larger,generalabove0.4m2,require micro-arc oxidation power supply is bigger,this subject a do pts the lanzhou university of technology institute of materials and development of MAO-300 type nc micro-arc oxidation production device(figure1)micro-arc oxidation on magnesium alloy wheel casting processing,its similar to ordinary anodic oxidation equipment,including special high-voltage power supply,micro-arc oxidation alkaline solution of electrolytic tank,mixing system,cooling system,workpiece with stainless steel plate for peer electrode.With micro-arc oxidation method in sodium silicate and sodium hydroxide electrolyte fluid system in the preparation of magnesium alloy wheel casting oxide ceramic membrane, the concrete technological process first set oxidation process parameters and the alkaline tank sodium silicate solution,the cleaning after micro-arc oxidation of magnesium alloy wheel casting into cell15~20min,clean with clear water tank2~4min,add ho t water in ho t water(80℃,10~15min),closed,then cool in the cold water tank2min,hoisted ou t drainage,drying,examine the hub.After micro-arc oxidation tr eatment must be closed by ho t water,formed by micro-arc oxidation discharge holes so the distribution of the channel and the surrounding a large number of micro cracks will be closed,prevent oxygen t o cause oxidation.After completion of micro-arc oxidation,from after micro-arc oxidation on magnesium alloy wheel casting intercept film sample were analyzed,and to facilitate test analysis,r equest samples made of circular plate,so the sample interception location choice among wheels,mo s t is shown in ing scanning electron microscope analysis of oxide filmFigure1MAO-300type nc micro-arc oxidation power supplyFigure2after micro-arc oxidation magnesium alloy wheel hub casting andinterception of membrane layer analysis sampleThree micro-arc oxidation process parameters on the quality of the film Based on the research of the sample and analysis of micro-arc oxidation technology is, in fact,the substrate magnesium magnesium oxide.Figure3for the dimension of samples before and after oxidation appearance schematic simulation,which is suitable for ceramic oxide film a outward growth,namely the increase of size part,b is the depth of the internal oxidation t o the matrix,a and b interface for initial sample surface position,h for the total thickness of oxide film.Figure3samples dimension changes before and after micro-arc oxidation diagram Larger influence on test has a positive voltage,frequency,duty cycle,current density and oxidation time on the process parameters.Due to the electric casting of magnesium alloy surface area is larger,micro-arc oxidation micro-arc discharge must be formed in the surface can occur after a certain thickness of oxide film,so the formation of the oxide film is needed for the voltage doesn't need much,the current is larger,the oxide film formation and the process of thickening,o ften accompanied by current and voltage mutation.When the oxide film thickness reaches a certain degree,the need t o increase the voltage on both ends of the workpiece,usually at ar ound150V in the micro arc discharge betw een the workpiece and the electrolyte.Increased with the increase of voltage,current,micro-arc density is mo r e and mo r e close,mo r e and mor e bright,and micro-arc constantly beating, basically,the current and voltage,linear increase abo u t180V voltage,the density of micro-arc basically meet the technological requirements,the current growth slowly.When the thickness of oxide film reaches a certain electricityFrom electric casting magnesium alloys is n o t hard t o find in the micro-arc oxidation test result analysis,micro-arc oxidation in the process can be divided into two steps, namely the oxide film formation stage and the stage of micro-arc oxidation film discharge, the formation of oxide film phase as the initial stage,the stage of the supply voltage is small,and after the film to pr oduce micro-arc discharge requires high voltage,for magnesium alloy electric casting the large workpiece with micro-arc oxidation processing surface area is larger,the film for a long time,t o a large extent affected the production efficiency.Experimental results also found that the dc power of oxide film faster than pulse power,in the absence of micro arc discharge,oxide film layer is not dense,it can be seenfrom appearance,need again with pulse power supply for micro-arc oxidation discharge, the oxide film become mo r e dense.In order to improve the production efficiency,to meet the n eed s of industrial production,suggest early low voltage adjustable dc constant voltage power supply are available t o set up the initial oxidation film,forming a complete insulation film in place to ensure that the first phase,and the oxide film in the late discharge can use digital pulse type adjustable power supply,it can shorten the artifacts of micro-arc oxidation time.The size of the current density in a certain extent reflects the intensity of micro-arc oxidation,strongly affect the resulting performance of the micro arc oxidation ceramic layer.The duration of oxidation also seriously affects the coating corrosion resistance: oxidation time is too short,although generat ed mainly the dense layer,bu t the film is too thin,don't have good corrosion resistance;After oxidation time is too long,at some time, with the increase of time,although the overall film thickness increases,bu t the increase is a loose layer,layer density and thinning trend,d o e s n ot favor the coating corrosion resistance,also no t economic.The density of micro arc also related with the pulse frequency,when the pulse frequency increases,the density of micro arc also gradually increased.Will have the electric field set up suddenly,can pr oduce micro arc.In the basic process parameters such as electrolyte concentration,duty ratio and pulse n umbe r of uncertain,the arc voltage is constant commonly,so when the frequency increases,the sustain micro-arc voltage frequency increases,the micro-arc density will increaseFour micro-arc oxide film layer structure characteristicsAfter micro-arc oxidation of magnesium alloy wheel hub interception by Mef3large metallurgical microscope observation of the sample,the micro-arc oxide film surface morphology as shown in figure4.Can be seen from the figure in the wheel hub surface layer is made up of many tiny"small volcanic cone"(figure pr otuberant part ar ound the holes)in dendritic combination,constitute the mesh structure."Small volcanic cone"center has a small hole,this is the electrolyte reaction with matrix micro-arc discharge channel, namely when the micro-arc spew ed molten oxide channel.In addition,because the current micro area local plasma channel is different that differ by the size of the hole,big hole are also distributed ar ound a large n u mbe r of micro cracks,the generation of micro cracks o ften related to the stress that exist in the film.With SSM Analysis Analysis software[6]toanalyze the surface density,including25m film for sample,the hole surface area ratio of 18%,that of micro-arc oxidation film density is better.Figure4magnesium alloy wheel hub micro-arc oxide film layer surface morphologyFigure5AM60B magnesium alloy micro-arc oxidation film section morphology by SEM Figure5is thr ough JMS-6700-f field emission scanning electron microscopy(sem) observed the micro-arc oxide film layer section morphology photos.Figure5shows the average film thickness of a bo u t22(including m,the oxide film and substrate with good, decomposition of a distinct,density on the interface is good,no big holes.By figure5can also see,micro-arc oxide film by the outermost layer of loose layer,the inside of the transition layer and layer in betw een density of three parts,the transitional layer is the interface film layer and substrate,holes and other defects existing in the loose layer,d ens e layer is the key t o improve its corrosion resistance.Figure6is obtained by Phlip X'pert X-ray diffractometer AM60B magnesium alloy wheel hub of micro-arc oxidation film XRD spectrum,according t o the intensity of diffraction peak accumulation analysis shows that the matrix of Mg peak relatively obvious, the main phase of micro-arc oxidation coating is cubic structure of MgO style,surface with Mg2Si2O4and MgAl2O4spinel phase,according t o the test conditions that may also contain SiO2,MgF2and small a mounts of Mg(OH)2,and the oxide of Al,K and Na. Studies have shown that MgAl2O4and Mg2Si2O4can improve the wear resistance of ceramic layer and MgO style the corrosion resistance of ceramic layer play a very important role.This is the micro-arc oxide film performance is higher than the r oot cause of the anode oxidation membrane performance.In addition,micro-arc oxidation ceramic layers of low porosity,and to improve the corrosion resistance of the coatings;Ceramic layer from the substrate on the growth,combined with matrix closely,therefore,is no t easy t o fall off.In addition,the technology can generat e uniform film both inside and outside the material surface layer,expand the scope of application of micro-arc oxidation.Figure6AM60B magnesium alloy micro-arc oxidation film XRD spectrum Five T o detect the corrosion resistance of the micro-arc oxide film layer In order t o meet the requirements of the use of electric cars,micro-arc oxidation on magnesium alloy electric wheel hub on the corrosion resistance test,salt spray testing machine mainly USES the WJ-90after micro-arc oxidation tr eatment of the surface of the wheel hub for salt spray test.After testing found that did not use h ot water seal processing of the surface of the wheel hub48h corrosion rate was0.108%,while only0.073%,afterho t water hole sealing hubs such as chromium than other chemical surface tr eatment processing of low corrosion rate(0.6%).[9],that magnesium alloy after micro-arc oxidation electric wheel hub surface corrosion resistance is superior.T o evaluate a r ough check the appearance of the film,feel is very good,membrane layer uniform light show that membrane surface appearance level is higher.Practice shows that without the micro-arc oxidation of the surface of the magnesium alloy wheel casting coating,its poor corrosion resistance,abrasion resistance,in a very short period of time,began to appear on the surface of parts oxidation falls off ph eno menon,it is difficult t o sell in the market; After micro-arc oxidation treatment,its corrosion resistance,wear-resisting performance is significantSix The conclusion(1)quality of micro-arc oxidation on magnesium alloy electric wheel hub surface influence factor has a positive voltage,frequency,duty cycle,current density and oxidation time on the process parameters.Optimum process parameters for150~180V voltage, current density of1.1A/dm2,oxidation time t o20min,400Hz frequency,duty cycle of 20%.(2)the oxide film is divided into two layers of loose layer and den se layer structure, the dense layer is the main body,the film formed by cubic structure of MgO style,the surface is MgO style and MgA12O4,spinel phase mixture,and combined with matrix and closely for hard ceramic layer and played a key role of the magnesium alloy surface anticorrosion(3)the micro-arc oxidation technology for new surface tr eatment technology of environmental protection,bu t its large area needed for the magnesium alloy casting film for a long time,the production efficiency is low,the mass production t o meet the large area of magnesium alloy castings,micro-arc oxidation power supply can be established by using dc power first initial oxidation film layer,then use pulse power arc discharge strengthening oxide film layer,the ways which are already so den se and har d ceramic oxide film layer can be obtained,also can greatly improve production efficiency.镁合金电动车轮毂微弧氧化生产研究国内外大多数电动车车辆配置为铝合金轮毂，其在质量、节能、减震、降噪和车辆动力学特性等指标大大低于镁合金。
毕业设计论文外文文献翻译中英文对照电气对中国智能电网的研究
1Research on Smart Grid in ChinaJingjing Lu, Da Xie, Member, IEEE and Qian Ai, Member, IEEEAbstract--The Smart Grid is the latest direction for the futurepower system development. In this paper, firstly the backgroundof Smart Grid, its meaning, as well as the concept and structurewere presented. Typical diagram of Smart Grid was illustrated.Then, the current development of Smart Grid in United States and Europe were described, development ideas and the future trends in these countries were summarized and compared as well.Besides, the driving force of Smart Grid in China was analyzed,with detailed introduction of current related projects in China.The relation between the UHV Power Grid and the Smart Grid was discussed. Finally, the potential role of Smart Grid in future power grids in China was prospected and a new direction for China’s Smart Grid development was charted.Index Terms—Smart Grid, UHV power grid, planning,operation, managementI. INTRODUCTIONWith the promotion of world economy modernization, theprice of oil has been kept on a upward trend. What is also noticeable is the shortage of energy supply around the world, the increasing pressures on resources and environment pressure, and the enormous power losses in energy delivery due to the low eff iciency of the current power grid. What’s more, owing to the growing electricity demands and the users’increasing requirements for reliability and quality, the power industry is now facing unprecedented challenges and opportunities. Therefore, a new sort of power system of environment friendly, economic, high performance, low investment, safety, reliability and flexibility has been a goal of engineers in power industry.Still, the emergence of advanced meter infrastructure and more extensive usage of the Internet accelerate the process [1]. Since 1990's, with the increasing use of distributed generation power, more demands and requirements have been proposed for power grid intensity [2], [3]. To find out a optimal solution for these problems, power companies should accept the idea of new technology adoption, potential mining of the existing power system and improvement of its application and utilization. Consensus has been reached by experts and scholars from different countries that future power gird must be able to meet various requirements of energy generating and the demands of highly market-oriented power transaction so that the needs of the self-selection from customers can be satisfied individually. All of these will become the future development direction of Smart Grid.This paper focuses on the status of the development of the Smart Grid, analyzing the driving force of the Smart Grid and introducing the current demonstration projects in China. It also discusses the relation between UHV power grid and Smart Grid, and then prospect the significance of Smart Grid in the future. A new direction for Chinese Smart Grid development is charted as well, which might be the reference for the development of Smart Grid in China.II. CONCEPT OF SMART GRIDSmart Grid is a gradual development process accompanied with the technology innovation, demands of energy saving and managements needs. People will have their own understandingfor Smart Grid, no matter if they are facility suppliers, IT companies, consulting firms, public power companies or power generation companies. From the earlier smart intelligence meteringto electrical intelligence, from transmission and distribution automation to a whole intelligent process, the concept of smart power grid has been enriched substantially [4]. In 2006, US IBM presented a "Smart Grid" solution. This is a relatively complete concept for current Smart Grid which indicates its official birth [5].As shown in Fig.1, a Smart Grid is basically overlaying the physical power system with an information system which links a variety of equipments and assets together with sensors to form a customer service platform. It allows the utility and consumers to constantly monitor and adjust electricity use. The management of operation will be more intelligent and scientific based on the dynamic analysis of needs both from user-side and demand side which can increase capital investment efficiency due to tighter design limits and optimized use of grid assets.In comparison with traditional grid, Smart Grid includes integrated communication systems, advanced Sensing,metering, measurement infrastructure, complete decision support and human interfaces.III. CURRENT RESEARCH ACTIVITIESA. Comparison of researches in Smart Grid area between European and the United statesIn the United States, there were several large power outages in recent years. Because of which, electric power industry pays closer attention to power quality and reliability;customers draw out more requests for electricity supply. The ever-increasing demands of national security and environmental protection policy of the United States leads to the establishment of a higher standard for power grid construction and management [6]. At the same time, in recent years’ researches of basic materials, power and information technologies, breakthroughs have been achieved for implementation target which shows the significant improvement of reliability, efficiency in power network. Such as the emergence of superconducting cables, it assures Obama’s new gove rnment of United States has seen the daylights of the Smart Grid.Similarly, the European power users also raise higher requirements for electricity supply & power quality [7].Because of the extreme attention for environmental protection,compared with the construction of power grid in US,Europeans have more concerns about the construction of renewable energy access, the impact on wildlife, as well as the actively research on real-time monitoring and remotecontrolling.All is about to realize the "Plug & Play use" idea,ensuring a more friendly, flexible access and interaction with the user. In both Europe and United States, the most common direction for grid development is to seek new and renewable sources for energy generation. However, Smart Grid is not a fixed, static project, according to their particular status and main problems, all countries need to simplify the Smart Grid and make it adjusted to fit their own features.B. Driving force of the Smart Grid in ChinaThe drivers for Smart Grid construction can be concluded into market, circumstances, safety and power quality. Chinese power industry is also facing the similar situation as in Europe and the United States.At Market-oriented reforms level, the national network and unified national electricity market has not completely formed.In national wide, power exchanges are not effective; neither does the true meaning of the online bidding. From a long term view,China's transaction approaches of power markets and pricing structure is developing, market demand and supply sides will have more frequent interactions. In order to attract more users to join the market competition, power companies must improve their service, strengthen the interaction with users and provide more products for selection, so as to meet the demands of different types of users.At the macro policy level, the power industry needs to meet the requirements ofresource-saving and environment-friendly society’s construction, adapt to climate change and suitable for sustainable development.Regarding the Chinese power grid itself, a strong backbone network has not been built yet, and it is still not strong enough to withstand multiple faults circumstances. The regional power grid backbone is also in a lower stability level, which results in a limited flexibility for system operation, etc. The snow storm weather in early 2008 which led to a blackout in major area of China vividly exposed the weakness of the current Chinese grid in safeguard of electricity supply aspect.Moreover, the lack of intelligent power distribution leads to a regional, seasonal shortage of electricity and coexistent in some areas with both surplus & shortages of electricity.There still remain challenges that how to improve the efficiency of power investment and construction, how to ensure the security and reliability of power grid’s operation, to ensure power quality; how to improve the maintenance of power system; how to enhance the service quality to users, as well as how to improve the power grid management in China.For these issues, Smart Grid would be an ideal solution.C. Current research activities in ChinaIn the year of 2006, IBM published the guideline named ‘Establishing Smart Power Grid and Innovating Management Methods – A New Thought of the Development of Electric in China’. Directed at the current opportunities and challenges of the power grid companies in China, the guideline suggests improving the efficiency of electrical investments and construction, the stability of power grid, and the companies’service and ma nagement level through the construction of smart power grid and the innovation of management methods.Meanwhile, IBM proposed that it can provide a whole scheme - Solution Architecture for Energy (SAFT) for the power companies in China to use the smart power grid effectively. SAFT contains several parts: first is to improvethe digital level by connecting the equipments with sensors;Second is to establish the data collecting and integrating system; Third is to analyze: SAFT optimize the operating progress and management based on the analyzing of the data[5]. This is the bud of smart power grid in Chin.In October 2007, East China Power Grid Company embarked on the research area of the feasibility of smart power grid. The research project was not only correlated with the progress of those advanced companies and research facilities abroad, but also take the current situation and future needs of east china power grid into consideration. The result came out as, based on the high equipment level and strong technological innovation ability, the construction of smart power grid is feasible in east china power grid. East China Power Grid Company would follow the belief that‘Concerning the future and change fast with needs, and providing high quality service’, when bui lding smart power grid. There is a three step strategy with an advanced power grid distributing center built by 2010, the construction of digital power grid with primary intelligence completed by 2020, and a smart power grid with the ability of self-healing built by 2030 [8]. The construction plan is still under consideration.On Feb. 28, 2009, as a part of the smart power grid of East China Power Grid Company, the three-state security defense and power generation monitoring system passed the acceptance check in Beijing, which stands for stable-state,transient-state and dynamic-state. The system integrated three single systems altogether for the first time, which includes power management system, power grid dynamic wan monitor system and online stability analysis and warning system. The operator has full access to the whole view of the power grid operating situation andthe decision-making assistance without switching in systems or platforms. Besides, the system can effectively improve the management standardization and the level of flow of the related power plants through establishing the management checking platform and the assistance marketservice quality analyzing platform.The development of smart power grid research in China is slow and far behind the west. So far, only East China Power Grid Company and North China Power Grid Company have carried out researches about the developing and implementation plan. It is a tradition for China to emphasize technology development, and in fact, the equipments in China are more advanced than those in developed countries. Thus,smart power grid has a bright prospect in China.IV. PROSPECTS OF SMART GRID IN CHINAIn order to solve the problems of imbalance distribution for generation resources and power loads, the transmission capacity should be enhanced by building long-distance and large-capacity power transmission systems. And unity or united UHV power grids should be constructed under coordinated plan. The transmission of power on a large scale from west and north China to middle and east China can reduce the pressure of energy in the east China and the pressure of transmission and environmental protection.Furthermore, this can expedite the conversion from resource advantage to economy advantage and realize the coordinated development of nation economy. Chinese politics system,economic environment and management system also promotes UHV power grids in its development. At present, China is studying the future large power grids technology and has the ability to construct the national united power grids. On Jan, 16,2009, the first UHV power line in China was finished and put into operation.Unity or united UHV power grid, distributed power generating or scattered interactive power supplying grid are the trends of development. China, as the delegate in unity or united UHV power grid development trend, is different from any western countries. In China, is it in contradiction to develop both UHV power grid and Smart Grid? Though the large power grid with linkage effect has the advantage of optimizing the resources, it has the potential risk of power outage in large area. The ability to control the large power grid and maintain its stability is required by the fast development of power grid. And the smart power gird with self-healing and high reliability matches such requirements.Thus, smart power grid is the direction of China power grid development while building UHV power grid and the grid of different level, as well as improving the operating and management level of the grid.According to the precondition and the background of UHVpower grid development in current China, the aspects which should be paid more attention on are as follows:Smart Planning: The power grid should become selfhealing and smart. The ability of power grid planning optimization should be enhanced. So should be the ability of receive-side power grid planning, on the premise of the UHV AC/ DC feed-in and differentvoltage level coordinated development. The most important thing is to change the concepts and methods of power planning, and to make the traditional power development concept such like regarding building new power stations as a wide-ranging concept of resourcesdistribution.Smart Operation: The dispatching pattern is developing towards a coordinated control direction, aiming at the enhancement of control and mastering of large power grid. The future Smart Grid should be coordinated with a matching control center equipped with more advanced power system management ability, for the purpose of improving the functions and performanceof existing EMS, MOS, WAMMAP system in an integral manner, at the same time to track down the correlations between different power grid monitoring and controlling indexes,and to construct a logic structure based power system monitoring and controlling index system. Through thegradual process of implementation of dynamic security monitoring, power system pre-alarm processing and precontrol,much more accurate and comprehensive knowledge of the operation state of the power systemcan be obtained, based on which, the most effective and timely measures and actions can be taken to fulfill the power system control and dispatching strategy, finally to improve the safeguard of the whole power system’sstability and security.Smart Management: The management pattern of power system is undergoing an evolution from vertical mode to distributed mode, from function management to process management, from grid construction to both construction and operation modes.V. CONCLUSIONSmart Grid is a hot spot in today's electric power system,also regarded as one of the vanes in 21st century for the major scientific and technological innovation and development in power system. Many countries in the world are involved in this big trend, and have set up a lot of Smart Grid demonstration projects and test platforms. Also, the theoretical and experimental research in Smart Grid has made some achievements. The international exchanges have greatly promoted the development of Smart Grid. Because of China's electricity distribution and extremely uneven distribution of electricity load, it is the right time to develop special highvoltage power grid. As the development of Smart Grid is still at the very beginning stage of our country, how to combine the special high-voltage power grids with intelligent power grid is the main problem confronted. The direction to development and the characteristics of smart power grids in China are still open for our experts and scholars for further study.VI. REFERENCES[1] David G. Hart, " Using AMI to Realize the Smart Grid," in Proc. 2008IEEE Power and Energy Society General Meeting - Conversion andDelivery of Electrical Energy in the 21st Century, pp. 1-2.[2] S. Massoud Amin and B.F. Wollenberg, “Toward a Smart Grid: powerdeli very for the 21st century,” IEEE Power and Energy Magazine, Vol.3, No. 5 Sept.-Oct. 2005, pp. 34-41.[3] D. Divan and H. Johal, “A Smarter Grid for Improving SystemReliability and Asset Utilization,” Power Electronics and MotionControl Conference, August, 2006.[4] Tai, H. and Hogain, E.O., “Behind the buzz [In My View]," IEEE Trans.Power and Energy Magazine, vol. 7, pp. 96 - 92, Mar.-Apr. 2009.[5] Fujie Sun, Ming Lei and Chengbin Yang, “Establishing Smart PowerGrid and Innovating Management Methods– A New Thought of theDevelopment of Electric in China," IBM Corp, [Online]. Available:[6] Richard E. Brown, " Impact of Smart Grid on distribution systemdesign," in Proc. 2008 IEEE Power and Energy Society General Meeting- Conversion and Delivery of Electrical Energy in the 21st Century, pp.1-4.[7] European Commission, Directorate-General for Research, “Draft -Strategic Deployment Document for Europe’s Electricity Networks ofthe future”, 2008[8] Junqing Shuai, Aiming at the forefront and Establishing SmartGrid, State Grid, issue 2, pp.54-57, 2008.VII. BIOGRAPHIESJingjing Lu was born in Hunan, China in 1985. Shereceived her B.Sc. degree in electrical engineeringfrom Shanghai Jiao Tong University, Shanghai,China in 200 . Now she is a gradate student ofDepartment of Electrical Engineering, Shanghai Jiaoong University in Shanghai, China. She mainlyfocuses her research on power system simulation,FACTS and Smart Grid.Da Xie (M’03) was born in Heilongjiang, China in1969. He received his B.Sc. degree in electricalengineering from Shanghai Jiao Tong University,Shanghai, China in 1991, the M.Sc. degree inelectrical engineering from Harbin Institute ofTechnology, Harbin, China in 1996,and the Ph.D.degree in electrical engineering from Shanghai JiaoTong University, Shanghai, China in 1999. Now heis associate professor in Shanghai Jiao TongUniversity, EE department. He mainly focuses hisresearch on FACTS and power system simulation.Qian Ai (M’03) was born in Hubei, China in1969.He received the B.Sc. degree in electricalengineering from Shanghai Jiao Tong University,Shanghai, China, the M.Sc. degree in electricalengineering from Wuhan University, Wuhan, China,and the Ph.D. degree in electrical engineering fromTsinghua University, Beijing, China. He worked asa Research Fellow from 1999 to 2002 in NanyangTechnological University, Singapore, and theUniversity of Bath, Bath, U.K. He is currently anAssociate Professor at Shanghai Jiao Tong University. His interests includepower system modeling, power quality, FACTS and Micro grid.对中国智能电网的研究摘要 -智能电网是电力系统的未来发展的新方向。
接触网优化英文资料原文
Optimization of Overhead Contact Lines forShinkansen Speed IncreasesIn order to increase Shinkansen operational speeds, we need to conduct development on the overhead contact line equipment that supplies power to rolling stock in addition to development for rolling stock. At the start of the tests using FASTECH360, we introduced a new overhead contact line system that replaces conventional compound overhead contact line equipment (hereafter “improved compound catenary equipment”). But, as sp eeds in tests increased, we found many problems due to the change of the height of the overhead contact lines and the arrangement of pantographs that were not major concerns at present operational speeds. We addressed those problems through simulations and tests using an actual train and finally gained a good perspective on supplying power in the speed range of 360 km/h.1. IntroductionUse of the heavy compound catenary equipment—the standard overhead contact line system for the Shinkansen—is limited to speeds of up to around 240 km/h. So, in order to carry out running tests at around 360 km/h, considerable improvement and development was required. Since the period from planning to start of the tests using FASTECH360 was only a year, we went to work on the development of the overhead contact line system taking into account shortening of the work period.2.Overhead Contact Line System Suitable for Increased SpeedAs is widely known, improving the wave propagation velocity of the overhead contact line shown in formula (1) is effective for increasing the running speed. For that reason, we have increased the tension of and decreased the weight of the contact wire.c= (T / r) 1/2 × 3.6 [km/h] · · · (1)T: Tension of the overhead contact line [N], r : Weight per unit length of the overhead contact line [kg/m] Table 1 and Fig. 1 shows the compound catenary equipment deployed for JR East Shinkansen.The “Higher tension heavy compound catenary equipment” in Table 1 is the overhead contact line system that was improved when we increased the speed of the Tohoku Shinkansen to 275 km/h, and the “CS heavy compound catenary equipment” is the system that was improved in tests 15 years before where we successfully increased the speed to 425 km/h using the STAR21 test train on the Joetsu Shinkansen.In the high speed running tests this time, performance equivalent to that of the CS heavy compound catenary equipment was required. We were concerned, however, that development and construction could not be done in time, because the section that needed improvement was as long as approx. 60 km (60 drums) between Sendai and Kitakami.3.Issues in Improvement of the Overhead Contact Line System3.1 Issues in Current Collection PerformanceIn running tests in 2003 using an operating train to get basic data for tests with FASTECH360, we measured remarkable strain (stress) on the contact wire over 1,000 μst at 360 km/h.We presumed the cause to be the compound effect of short intervals of 50 m for pantographs of the test train, single-arm contact strips and heavy pull-off arms. Also, we thought that another cause was that wave propagation was prevented because sufficient wave propagation velocity was not secured due to loose tension of the auxiliary messenger wire. 3.2 Issues in ConstructionWhen we conducted improvement work of the CS heavy compound catenary equipment for the running tests of STAR21, for example, it took three days to improve one drum length (see Table 4). It was clear that if applying the same work method to the improvement this time, work would take more than half a year. Considering that and a balanced schedule with other maintenance work, we had to drastically shorten the work period.4.. Development of Overhead Contact Lines with Good CurrentCollection Performance and Easy Improvability In improvements to enable a higher tension heavy compound catenary equipment to handle 360 km/h running, we set the following targets as requirements to improve the current collection performance and,at the same time, to allow effective work.1) Approx. 500 km/h1)* wave propagation velocity for the contactwire2) No change of the total tension of the overhead contact linesystem to avoid modification of support components3) Shortening the work period to 2/3 that of past work*1) Train speed ≤ wave propagation velocity multiplied by approx. 0.7 or 0.8 is desirable.In order to achieve 1), we made the diameter of the contact wire thinner (lighter in weight), from 170 mm2 to 110 mm2, and increased the tension from 17.6 kN to 19.6 kN.Regarding 2), to maintain 53.9 kN total tension of the overhead contact line system, the total tension of the messenger wire and the auxiliary messenger wire needed to be decreased. As for the CS system, we decided to decrease the tension of the auxiliary messenger wire while keeping the tension of the messenger wire the same; but that could result in insufficient wave propagation velocity of the auxiliary messenger wire.And, since we kept the tension of the messenger wire as-is in spite of the lighter contact wire, we had to replace all droppers to maintain the height of the contact wire. That work took a lot of time and manpower.Accordingly, we tested a method of reducing the tension of the messenger wire according to the reduced tension of the messenger wire, to eliminate the replacement work of droppers.Also, we added thatreduced weight of the contact wire to the auxiliary messenger wire to improve the wave propagation velocity up to the test speed (360 km/h) with an aim of improving the current collection performance.Formula (2) shows the calculation of the dip in the catenary curve D (see Fig. 2).D=x · (S-X) · r /2T · · · (2)S: Span length, T and r : As in Formula (1)Since the unit weight of the overhead contact line system is changed from 4.33 kg to 3.83 kg due to the introduction of 110 mm2 diameter contact wire, approx. 21.6 kN tension of the messenger wire is desirable based on Formula (2).Table 2 shows the specs of the improved compound catenary equipment for the tests this time.5. Verification of Workability and Current Collection Performance ofthe Overhead Contact Lines5.1 WorkabilityFirst, we verified the dropper length of the higher tension heavy compound catenary equipment (before improvement) and the improved compound catenary equipment. Table 3 indicates the comparison results at the 50 m span length.The difference of the dropper length is within a few millimeters at other span lengths also. Therefore, replacement of droppers is not required. In this way, we could drastically simplify the improvement work compared to the CS heavy compound catenary equipment, as shown in TableAs shown in the above table, we could shorten the improvement work time of almost three days to two days. For the change of the tension of the messenger wire (replacement of anchor yokes), one of our partner companies developed a special jig to shorten the work time.The comparison of before and after the improvement work using the data of an electric and track inspection car proved that the status before the improvement such as the height and deviation of the overhead contact lines could be duplicated well; and almost no adjustment after the work was needed. 5.2 Current Collection PerformanceIn addition to shortening the work period, we aimed at reducing the stress of the contact wire by increasing the tension of the auxiliary catenary wire, and examined that effect by simulation. Fig. 3 and 4 show part of the simulation results.The simulations showed that the maximum uplift of the contact wire considerably decreased from 70 mm to 35 mm just as the contact force decreased as shown in Fig. 3. That suggests that the fatigue (stress) of the contact wire could be eased.The contact loss ratio, which increased as shown in Fig. 4, could be kept within the allowable range of 30%. Since it has been confirmed that multi-fractioned contact strips with less weight of movable parts significantly reduces contact loss, we expect that the actual contact loss ratio can be reduced to only a few percent.6. Obstructions to Stable Current Collection6.1 Change of the Height of the Overhead Contact LinesAfter starting the tests, we could observe favorable current collection including better contact loss ratio than expected; but as the running speed increased, we suddenly faced an event where many contact loss cases occurred in a certain section (drum). Fig. 6 shows the event. As we tried running with only one pantograph that was considered difficult, reduction of contact loss was an issue to be overcome.We found a large contact loss that occurred in every supporting point as a characteristicof the section with many contact losses. So, assuming that the contact loss occurred due to the change of the height of the overhead contact lines between the supporting points, we compared the change of that height and the contact loss ratio between drums2)* (see Fig. 7). *2: The unit length between anchors of the line is called a drum.Checking the height chart of the contact wire taken by an inspection car, we found that the deviation was caused by pre-sagging of the contact wire (see Fig. 8).Since the simulation also confirmed that approx. 30 mm Pre-sagging caused significant increase of contact losses in the 360 km/h speed range, we immediately added work to eliminate pre-sagging3)*.*3) Pre-sagging: Giving sag to overhead contact lines taking in account uplifting by pantographs.Replacing pantographs4)* significantly improved contact losses too and almost nocontact losses occurred after the pre-sagging elimination work as shown in Fig. 9. We could thus confirm the effect of those countermeasures.*4) We replaced pantographs with the low-noise ones that have single arms and higher compliance characteristics from multi-fractioned contact strips.Pre-sagging had been originally taken to improve current collection performance; but we found that it is better to keep the height of the overhead contact lines the same as much as possible in the high speed range over 300 km/h.6.2 Pantograph Interval and Dynamic CharacteristicsSince our actual trains with the highest speed are coupled Shinkansen exclusive cars and cars for through service on conventional and Shinkansen lines, we carried out the tests using a coupled train of two train sets.Fig. 10 briefly illustrates the tested train sets. Pantographs are the above-mentioned low-noise type.In the test with those train sets, we observed interesting results regarding contact loss.Fig. 11 shows that while the contact loss ratio in the 360 km/h speed range on the outbound line was in some sections in excess of the 10% that is considered good due to bad overlap configuration etc, that was mostly by just a few percent; and the duration of contact loss was shorter than a few tens of milliseconds, the standard of the good contact loss ratio. On the other hand, on the inbound line, the duration of contact loss was less than 100 ms, but the contact loss ratio reached nearly 30%, the worst acceptable standard.We considered that the cause of the difference between the outbound and inbound lines was the difference of the interval of pantographs; so, we carried out a study for improvement.As shown in Fig. 12, the simulation clarified that rear pantographs only contacted the contact wire weakly at a 138 m interval; so, those easily lost contact at speeds over 275 km/h.Accordingly, we changed the intervals of current collecting pantographs as shown in Fig. 13 to test the effect of the intervals.The contact loss ratio per interval is as shown in Fig. 14. In the tests, the running speedwas 275 km/h and the results shown are the results of the rear pantographs.The order of better results isThe order clarifies that the contact loss ratio is affected by wave propagation and reflection too; so, longer pantograph intervals are not always better.Looking at the characteristics of pantographs in each pattern, rear pantographs are positioned in the running direction at 246 m and 138 m intervals, while those are positioned on the opposite direction5)* at 91 m and 198 m intervals. In this context, we can estimate that contact loss is affected not only by pantograph intervals, but also by the characteristics of pantographs including differences in aerodynamic characteristics based on the direction.*5: The > direction to the ← running direction.Since pantographs in the running direction cannot generate sufficient lifting force and the insufficient contact to the contact wire could cause much contact loss, we carried out the test while increasing stationary uplifting force of rear pantographs.As the simulation results in Fig. 15 show, we expect that contact loss ratio can be improved to approx. 10%—the standard good ratio—with 138 m pantograph intervals by increasing the stationary uplifting force from 54 N to 74 N.Fig. 16 shows the test results of the contact loss ratio with the increased uplifting force.We could mostly reduce the contact loss ratio to less than 10% as expected from the simulation results. Comparing that to the results in Fig. 11, we were able to confirm a large improvement effect.7. High Speed Suitability of High-Speed Simple Catenary EquipmentI have expained up to now about the tests for the compound catenary equipment. Now I will introduce the tests for the simple catenary equipment used in the projected Shinkansen line section.Comparing simple catenary equipment and compound catenary equipment, change of the spring constant within a span (rate of uplifting force of a pantograph to the uplift of a contact line) is larger in a simple system. Furthermore, simple catenary equipment has a unique structural characteristic where large vibration remains after passing of a pantograph. In this context, we were concerned with deterioration of current collection performance of simple catenary equipment.In order to equalize the spring constant to reduce residual vibration, it could be effective to insert spring hangers that have attenuation performance (hereafter “damper hanger s”).Fig. 17 shows an example of calculation for a 50 m span. The figure shows that the values of hangers near supporting points (2.5 m and 7.5 m from the supporting point) are remarkably large; so, the spring constant within a span can be equalized by inserting damper hangers there.We thus introduced damper hangers to a section between the Iwate Ichinohe tunnel and the Ninohe station to check the effect.Fig. 18 and 19 respectively show examples of the observed results of the uplift of the contact wire and the strain.As shown in Fig. 17, the results with damper hangers recorded larger values for the uplift of the contact wire because the spring constant at the supporting point became smaller. Still, the values were under the target value of 100 mm.As for strain, we found no distinct difference between cases with and without damper hangers. Although larger uplift usually results in larger bending stress (strain), elasticity of springs probably broughtabout that effect in this case.But, we have to pay attention to the fact that the strain exceeded the target value of 500 μ at speeds over 300 km/h.In order to solve this problem, it would be effective to replace pull-off arms with lighter ones equivalent to those that have been deployed to the sections with the compound system and to replacethe contact wire with PHC (Precipitation-Hardened Copper Alloy) contact wire.Now, Fig. 20 shows the result of contact loss ratio.Regardless whether or not damper hangers are used, we could achieve good contact loss ratio less thana few percent.8.Future MaintenanceFinally, I would like to go over some trends for future maintenance.8.1 Replacement Period of Contact WireBased on the test results of the FASTECH360, we will increase the tension from 17.6 kN to 19.6 kN while continuing use of 170 mm2 diameter contact wire to achieve 320 km/h operation speed. That might lead to smaller allowable wear, and we are thus concerned about a shorter lifespan.On the other hand, the number of pantographs that slide on the contact wire will be reduced (for example, the number of pantographs of Hayate-Komachi type Shinkansen will be reduced from four to two because single train set will use only one pantograph); so, we can expect longer lifespan.For the time being, we will be watching the results of those conflicting effects.8.2 New Equipment Diagnosis MethodRecent advances in optical sensing technology have enabled easier measurement at points where high voltage is applied, and a measurement method of the contact force of pantographs to the contact wire is even allowing for multi-fractioned contact strips to be established.If we can identify the contact force of pantographs, we can expect the following new equipment diagnosis methods to be established.· Continuous measurement of the stress on the contact wire that we can now measure only at fixed points· Daytime measurement of contact loss that we can now measure only at night or in tunnels · Detection of improper equipment structure such as bad overlap configuration· Estimation of progress of wear of contact wire9. ConclusionWe have repeated running tests for almost three years since 2005. The test results are being applied to the coming increase of operation speed to 320 km/h, and the equipment and facilities are being improved right now.Based on the tests, we gained a perspective on stably supplying power in the 360 km/h speed range. I hope this paper will pass down valuable data to future railways in the process of increasing speeds.为提高新干线速度所做的接触网优化为了增加新干线的运行速度，我们需要进行的接触网设备的供应，除了机车车辆的开发能力，机车车辆的发展。
(完整版)电气专业中英文对照翻译毕业设计论文
优秀论文审核通过未经允许切勿外传Chapter 3 Digital Electronics3.1 IntroductionA circuit that employs a numerical signal in its operation is classified as a digital circuitputers,pocket calculators, digital instruments, and numerical control (NC) equipment are common applications of digital circuits. Practically unlimited quantities of digital information can be processed in short periods of time electronically. With operational speed of prime importance in electronics today,digital circuits are used more frequently.In this chapter, digital circuit applications are discussed.There are many types of digital circuits that electronics, including logic circuits, flip-flop circuits, counting circuits, and many others. The first sections of this unit discuss the number systems that are basic to digital circuit understanding. The remainder of the chapter introduces some of the types of digital circuits and explains Boolean algebra as it is applied to logic circuits.3.2 Digital Number SystemsThe most common number system used today is the decimal system,in which 10 digits are used for counting. The number of digits in the systemis called its base (or radix).The decimal system，therefore，the counting process. The largest digit that can be used in a specific place or location is determined by the base of the system. In the decimal system the first position to the left of the decimal point is called the units place. Any digit from 0 to 9 can be used in this place.When number values greater than 9 are used,they must be expressed with two or more places.The next position to the left of the units place in a decimal system is the tens place.The number 99 is the largest digital value that can be expressed by two places in the decimal system.Each place added to the left extends the number system by a power of 10.Any number can be expressed as a sum of weighted place values.The decimal number 2583,for example, is expressed as (2×1000)+(5×100)+(8×10)+(3×1).The decimal number system is commonly used in our daily lives. Electronically, the binary system.Electronically,the value of 0 can be associated with a low-voltage value or no voltage. The number 1 can then be associated with a voltage value larger than 0. Binary systems that use these voltage values are said to , this chapter.The two operational states of a binary system,1 and 0,are natural circuit conditions. When a circuit is turned off or the off, or 0,state. An electrical circuit that the on，or 1,state. By using transistor or ICs，it is electronically possible to change states in less than a microsecond. Electronic devices make it possible to manipulate millions of 0s and is in a second and thus to process information quickly.The basic principles of numbering used in decimal numbers apply ingeneral to binary numbers.The base of the binary system is 2,meaning that only the digits 0 and 1 are used to express place value. The first place to the left of the binary point,or starting point，represents the units，or is,location. Places to the left of the binary point are the powers of 2.Some of the place values in base 2 are 2º=1,2¹=2,2²=4,2³=8,2⁴=16,25=32,and 26=64.When bases other than 10 are used,the numbers should example.The number 100₂(read“one,zero,zero, base 2”)is equivalent to 4 in base 10,or 410.Starting with the first digit to the left of the binary point,this number this method of conversion a binary number to an equivalent decimal number，write down the binary number first. Starting at the binary point，indicate the decimal equivalent for each binary place location where a 1 is indicated. For each 0 in the binary number leave a blank space or indicate a 0 ' Add the place values and then record the decimal equivalent.The conversion of a decimal number to a binary equivalent is achieved by repetitive steps of division by the number 2.When the quotient is even with no remainder,a 0 is recorded.When the quotient process continues until the quotient is 0.The binary equivalent consists of the remainder values in the order last to first.3.2.2 Binary-coded Decimal (BCD) Number SystemWhen large numbers are indicated by binary numbers，they are difficult to use. For this reason，the Binary-Coded Decimal(BCD) method of counting was devised. In this system four binary digits are used to represent each decimal digit.To illustrate this procedure，the number 105，is converted to a BCD number.In binary numbers，To apply the BCD conversion process，the base 10 number is first divided into digits according to place values.The number 10510 gives the digits 1-0-5.Converting each displayed by this process with only 12 binary numbers. The between each group of digits is important when displaying BCD numbers.The largest digit to be displayed by any group of BCD numbers is 9.Six digits of a number-coding group are not used at all in this system.Because of this, the octal (base 8) and the binary form but usually display them in BCD,octal,or a base 8 system is 7. The place values starting at the left of the octal point are the powers of eight: 80=1,81=8,82=64,83=512,84=4096,and so on.The process of converting an octal number to a decimal number is the same as that used in the binary-to-decimal conversion process. In this method, equivalent decimal is 25810.Converting an octal number to an equivalent binary number is similar to the BCD conversion process. The octal number is first divided into digits according to place value. Each octal digit is then converted into an equivalent binary number using only three digits.Converting a decimal number to an octal number is a process of repetitive division by the number 8.After the quotient determined，the remainder is brought down as the place value.When the quotient is even with no remainder，a 0 is transferred to the place position.The number for converting 409810 to base 8 is 100028.Converting a binary number to an octal number is an importantconversion process of digital circuits. Binary numbers are first processed at a very output circuit then accepts this signal and converts it to an octal signal displayed on a readout device.must first be divided into groups of three，starting at the octal point.Each binary group is then converted into an equivalent octal number.These numbers are then combined，while remaining in their same respective places，to represent the equivalent octal number.3.2.4 Hexadecimal Number SystemThe digital systems to process large number values.The base of this system is 16，which means that the largest number used in a place is 15.Digits used by this system are the numbers 0-9 and the letters A-F. The letters A-P are used to denote the digits 10-15，respectively. The place values to the left of the .The process of changing a proper digital order.The place values，or powers of the base，are then positioned under the respective digits in step 2.In step 3，the value of each digit is recorded. The values in steps 2 and 3 are then multiplied together and added. The sum gives the decimal equivalent value of a . Initially，the converted to a binary number using four digits per group. The binary group is combined to form the equivalent binary number.The conversion of a decimal number to a ，as with other number systems. In this procedure the division is by 16 and remainders can be as large as 15.Converting a binary number to a groups of four digits，starting at the converted to a digital circuit-design applications binary signals arefar superior to those of the octal，decimal，or be processed very easily through electronic circuitry，since they can be represented by two stable states of operation. These states can be easily defined as on or off, 1 or 0，up or down，voltage or no voltage，right or left，or any other two-condition states. There must be no in-between state.The symbols used to define the operational state of a binary system are very important.In positive binary logic，the state of voltage，on，true，or a letter designation (such as A ) is used to denote the operational state 1 .No voltage，off，false，and the letter A are commonly used to denote the 0 condition. A circuit can be set to either state and will remain in that state until it is caused to change conditions.Any electronic device that can be set in one of two operational states or conditions by an outside signal is said to be bistable. Relays，lamps，switches，transistors, diodes and ICs may be used for this purpose. A bistable device .By using many of these devices，it is possible to build an electronic circuit that will make decisions based upon the applied input signals. The output of this circuit is a decision based upon the operational conditions of the input. Since the application of bistable devices in digital circuits makes logical decisions，they are commonly called binary logic circuits.If we were to draw a circuit diagram for such a system，including all the resistors，diodes，transistors and interconnections，we would face an overwhelming task, and an unnecessary one.Anyone who read the circuit diagram would in their mind group the components into standard circuits and think in terms of the" system" functions of the individual gates. Forthis reason，we design and draw digital circuit with standard logic symbols. Three basic circuits of this type are used to make simple logic decisions.These are the AND circuit, OR circuit, and the NOT circuit.Electronic circuits designed to perform logic functions are called gates.This term refers to the capability of a circuit to pass or block specific digital signals.The logic-gate symbols are shown in Fig.3-1.The small circle at the output of NOT gate indicates the inversion of the signal. Mathematically，this action is described as A=.Thus without the small circle，the rectangle would represent an amplifier (or buffer) with a gain of unity.An AND gate the 1 state simultaneously，then there will be a 1 at the output.The AND gate in Fig. 3-1 produces only a 1 out-put when A and B are both 1. Mathematically，this action is described as A·B=C. This expression shows the multiplication operation. An OR gate Fig.3-1 produces a when either or both inputs are l.Mathematically，this action is described as A+B=C. This expression shows OR addition. This gate is used to make logic decisions of whether or not a 1 appears at either input.An IF-THEN type of sentence is often used to describe the basic operation of a logic state.For example，if the inputs applied to an AND gate are all 1，then the output will be 1 .If a 1 is applied to any input of an OR gate，then the output will be 1 .If an input is applied to a NOT gate，then the output will be the opposite or inverse.The logic gate symbols in Fig. 3-1 show only the input and output connections. The actual gates，when wired into a digital circuit, would pin 14 and 7.3.4 Combination Logic GatesWhen a NOT gate is combined with an AND gate or an OR gate，it iscalled a combination logic gate. A NOT-AND gate is called a NAND gate，which is an inverted AND gate. Mathematically the operation of a NAND gate is A·B=. A combination NOT-OR ，or NOR，gate produces a negation of the OR function.Mathematically the operation of a NOR gate is A+B=.A 1 appears at the output only when A is 0 and B is 0.The logic symbols are shown in Fig. 3-3.The bar over C denotes the inversion，or negative function，of the gate.The logic gates discussed .In actual digital electronic applications，solid-state components are ordinarily used to accomplish gate functions.Boolean algebra is a special form of algebra that was designed to show the relationships of logic operations.Thin form of algebra is ideally suited for analysis and design of binary logic systems.Through the use of Boolean algebra，it is possible to write mathematical expressions that describe specific logic functions.Boolean expressions are more meaningful than complex word statements or or elaborate truth tables.The laws that apply to Boolean algebra are used to simplify complex expressions. Through this type of operation it may be possible to reduce the number of logic gates needed to achieve a specific function before the circuits are designed.In Boolean algebra the variables of an equation are assigned by letters of the alphabet.Each variable then exists in states of 1 or 0 according to its condition.The 1，or true state，is normally represented by a single letter such as A，B or C.The opposite state or condition is then described as 0，or false，and is represented by or A’.This is described as NOT A，A negated，or A complemented.Boolean algebra is somewhat different from conventional algebra withrespect to mathematical operations.The Boolean operations are expressed as follows:Multiplication:A AND B，AB，,A·BOR addition:A OR B .A+BNegation，or complementing:NOT A，，A’Assume that a digital logic circuit only C is on by itself or when A，B and C are all on expression describes the desired output. Eight (23) different combinations of A，B，and C exist in this expression because there are three，inputs. Only two of those combinations should cause a signal that will actuate the output. When a variable is not on (0)，it is expressed as a negated letter. The original statement is expressed as follows: With A，B，and C on or with A off, B off, and C on ，an output (X）will occur:ABC+C=XA truth table illustrates if this expression is achieved or not.Table 3-1 shows a truth table for this equation. First，ABC is determined by multiplying the three inputs together.A 1 appears only when the A，B，and C inputs are all 1.Next the negated inputs A andB are determined.Then the products of inputs C，A，and B are listed.The next column shows the addition of ABC and C.The output of this equation shows that output 1 is produced only when C is 1 or when ABC is 1.A logic circuit to accomplish this Boolean expression is shown in Fig. 3-4.Initially the equation is analyzed to determine its primary operational function.Step1 shows the original equation.The primary function is addition，since it influences all parts of the equation in some way.Step 2 shows the primary function changed to a logic gate diagram.Step 3 showsthe branch parts of the equation expressed by logic diagram，with AND gates used to combine terms.Step 4 completes the process by connecting all inputs together.The circles at inputs，of the lower AND gate are used to achieve the negative function of these branch parts.The general rules for changing a Boolean equation into a logic circuit diagram are very similar to those outlined.Initially the original equation must be analyzed for its primary mathematical function.This is then changed into a gate diagram that is inputted by branch parts of the equation.Each branch operation is then analyzed and expressed in gate form.The process continues until all branches are completely expressed in diagram formmon inputs are then connected together.3.5 Timing and Storage ElementsDigital electronics involves a number of items that are not classified as gates.Circuits or devices of this type the operation of a system.Included in this system are such things as timing devices，storage elements，counters，decoders，memory，and registers.Truth tables symbols，operational characteristics，and applications of these items will be presented an IC chip. The internal construction of the chip cannot be effectively altered. Operation is controlled by the application of an external signal to the input. As a rule，very little work can be done to control operation other than altering the input signal.The logic circuits in Fig. 3-4 are combinational circuit because the output responds immediately to the inputs and there is no memory. When memory is a part of a logic circuit，the system is called sequential circuit because its output depends on the input plus its an input signal isapplied.A bistable multivibrator，in the strict sense，is a flip-flop. When it is turned on，it assumes a particular operational state. It does not change states until the input is altered.A flip-flop opposite polarity.Two inputs are usually needed to alter the state of a flip-flop. A variety of names are used for the inputs.These vary a great deal between different flip-flops.1. R-S flip-flopsFig.3-5 shows logic circuit construction of an R-S flip-flop. It is constructed from two NAND gates. The output of each NAND provides one of the inputs for the other NAND. R stands for the reset input and S represents the set input.The truth table and logic symbol are shown in Fig. 3-6.Notice that the truth table is somewhat more complex than that of a gate. It shows, for example，the applied input, previous output，and resulting output.To understand the operation of an R-S flip-flop，we must first look at the previous outputs.This is the status of the output before a change is applied to the input. The first four items of the previous outputs are Q=1 and =0. The second four states this case of the input to NANDS is 0 and that is 0，which implies that both inputs to NANDR are 1.By symmetry，the logic circuit will also stable with Q0 and 1.If now R momentarily becomes 0，the output of NANDR，，will rise to resulting in NANDS be realized by a 0 at S.The outputs Q and are unpredictable when the inputs R and S are 0 states.This case is not allowed.Seldom would individual gates be used to construct a flip-flop，rather than one of the special types for the flip-flop packages on a single chipwould be used by a designer.A variety of different flip-flops are used in digital electronic systems today. In general，each flip-flop type R-S-T flip-flop for example .is a triggered R-S flip-flop. It will not change states when the R and S inputs assume a value until a trigger pulse is applied. This would permit a large number of flip-flops to change states all at the same time. Fig. 3-7 shows the logic circuit construction. The truth table and logic symbol are shown in Fig. 3-8. The R and S input are thus active when the signal at the gate input (T) is 1 .Normally，such timing，or synchronizing，signals are distributed throughout a digital system by clock pulses，as shown in Fig. 3-9.The symmetrical clock signal provides two times each period.The circuit can be designed to trigger at the leading or trailing edge of the clock. The logic symbols for edge trigger flip-flops are shown in Fig.3-10.2. J-K flip-flopsAnother very important flip-flop unpredictable output state. The J and K inputs addition to this，J-K flip-flops may employ preset and preclear functions. This is used to establish sequential timing operations. Fig.3-11 shows the logic symbol and truth table of a J-K flip-flop.3. 5. 2 CountersA flip-flop be used in switching operations，and it can count pulses.A series of interconnected flip-flops is generally called a register.Each register can store one binary digit or bit of data. Several flip-flops connected form a counter. Counting is a fundamental digital electronic function.For an electronic circuit to count，a number of things must beachieved. Basically，the circuit must be supplied with some form of data or information that is suitable for processing. Typically，electrical pulses that turn on and off are applied to the input of a counter. These pulses must initiate a state change in the circuit when they are received. The circuit must also be able to recognize where it is in counting sequence at any particular time. This requires some form of memory. The counter must also be able to respond to the next number in the sequence. In digital electronic systems flip-flops are primarily used to achieve counting. This type of device is capable of changing states when a pulse is applied，output pulse.There are several types of counters used in digital circuitry today.Probably the most common of these is the binary counter.This particular counter is designed to process two-state or binary information. J-K flip-flops are commonly used in binary counters.Refer now to the single J-K flip-flop of Fig. 3-11 .In its toggle state，this flip-flop is capable of achieving counting. First，assume that the flip-flop is in its reset state. This would cause Q to be 0 and Q to be 1 .Normally，we are concerned only with Q output in counting operations. The flip-flop is now connected for operation in the toggle mode. J and K must both be made the 1 state. When a pulse is applied to the T，or clock，input，Q changes to 1.This means that with one pulse applied，a 1 is generated in the output. The flip-flop the next pulse arrives，Q resets，or changes to 0. Essentially，this means that two input pulses produce only one output pulse. This is a divide-by-two function.For binary numbers，counting is achieved by a number of divide-by-two flip-flops.To count more than one pulse，additional flip-flops must be employed. For each flip-flop added to the counter，its capacity is increased by the power of 2. With one flip-flop the maximum count was 20，or 1 .For two flip-flops it would count two places，such as 20 and 21.This would reach a count of 3 or a binary number of 11.The count would be 00，01，10，and 11. The counter would then clear and return to 00. In effect, this counts four state changes. Three flip-flops would count three places，or 20，21，and 22.This would permit a total count of eight state changes.The binary values are 000，001，010，011，100，101，110 and 111.The maximum count is seven，or 111 .Four flip-flops would count four places，or 20，21，22，and 23.The total count would make 16 state changes. The maximum count would be 15，or the binary number 1111.Each additional flip-flop would cause this to increase one binary place.河南理工大学电气工程及其自动化专业中英双语对照翻译。
接触网外文翻译文献
接触网外文翻译文献(文档含中英文对照即英文原文和中文翻译)Development of Feeder Messenger Wire Type Overhead Contact Line withOne Copper Messenger WireTakahiro HAMADA Atsushi IWAINAKA Researcher, Former Researcher, Contact Line Structures, Power Supply Technology Div.Feeder messenger wire type overhead contact lines have drawn attention recently from the viewpoint of labor-saving for maintenance. A type that uses two PH356mm2 messenger wires was introduced into the Tokyo district, while another that uses an SBTACSR730mm2 messenger wire into the Kansai district. In terms of the number of messenger wires, the one-wire type is more useful, as it involves a smaller number of parts. As the material for the wire, copper is better than aluminum, since it does not require connection with different metals. To realize the advantages of the two systems, therefore, we developed a feeder messenger wire type overhead contact line that has only one copper messenger wire.Keywords: feeder messenger wire type overhead contact line, PH730mm2 messenger wire, current collecting characteristics1. IntroductionFeeder messenger wire type overhead contact lines have a structure to combine the function of feeder with the messenger wire. They have drawn attention recently in Japan from the viewpoint of labor-saving for maintenance. They use two hard-drawn copper stranded conductor PH356mm2 messenger wires in the Tokyo district and an aluminum conductor steel-reinforced SBTACSR730mm2 messenger wire in the Kansai district. In terms of the number of messenger wires, the one-wire type is more useful as it involves a smaller number of parts, and copper is better as the material for the wire than aluminum since it does not require connection with different metals. Therefore, we promoted this research for the purpose of developing a feeder messenger wire type overhead contact line that has only one copper messenger wire to realize the advantages of the two systems.In order to determine what wires suit the new overhead contact line, we chose a narrow-gauge line in Tokyo as a test site, studied whether electrical and mechanical characteristics of wires satisfy the standard values, and examined the current collecting characteristics of various types of wires through simulation. As a result, it was proved that the PH730mm2 messenger wire was the most appropriate in the overcrowded railway sections in Tokyo.Based on this result, we actually constructed a PH730mm2 messenger wire and investigated its current collecting characteristics by using current collection testing equipment to find that standard values were all satisfied at the speed of 160 km/h. It was also proved that this wire type could be used for operation at speeds up to 160 km/h.2. Examination of the optimum wiresTable 1 lists the wires examined as candidates of one onemessenger wire. We examined the current capacity, wire resistance, tensile strength, minimum hanger length and current collecting characteristics, to determine the applicabilityTable 1 Dimensions of wire2.1 Current capacityWe examined whether the wire temperature is below the allowable limit at the conditions in Table 2. The allowable temperature is 90 ℃for the hard drawn copperstranded conductor (PH) and 150 ℃for the thermalproofhard drawn copper stranded conductor (THDC).Figure 1 shows the wire temperature rises when a currentof 855 A, which is the maximum value for wiresused in Tokyo, flows for 3,600 seconds. The shaded portionrepresents the surrounding temperature of 35 ℃,Table 2 Conditions of temperature calculationFig. 1 Wire temperature risesand the portion of slash mark the temperature rises by the Joule heat. There are no wires of THDC or PH that show a temperature rise over the allowable limit under thiscondition.2.2 Wire resistanceTo evaluate the wire resistance, we compared several kinds of messengers with two PH356mm2 messenger wires currently used on the narrow-gauge lines in Tokyo. In Fig. 2, the slash lined bars show the resistance after the temperature rise at an 855 A current flow and the shaded bars show the wire resistance at 20 ℃. A comparison of the resistance of two PH356mm2 wires with that of test wires at 20 ℃(shaded bar), proves that the resistance of THDC670mm2 wire and PH670mm2 wire is higher than that of two PH356mm2 wires. Moreover, in the case of the resistance after temperature rise (slash), only the resistance of THDC670mm2 wire and PH670mm2 wire is higher than that of two PH356mm2 wires.Fig. 2 Wire resistance2.3 Tensile strengthSince it is assumed that this catenary system is constructed to a standard tension of 39.2 kN, it is a condition that the tensile strength is set at over 86.24 kN, as the safety factor of copper is 2.2 in Japan. All the tensile strengths for the test wires referred to in this paper are over 86.24 kN.2.4 Minimum hanger lengthWe calculated the minimum hanger length on the assumption that the messenger wire tension is 39.2 kN; contact wire tension is 14.7 kN; and span length is 50 m. When we assume a standard system height (850 mm) equivalent to that of existing feeder messenger wire type overhead contact line in Tokyo, only the minimum hanger length of PH840mm2 wire is less than 150 mm. If the system height is assumed to be 960 mm, the minimum hanger length of PH840mm2 wire is larger than 150 mm.2.5 Current collecting characteristicsWe calculated the contact loss rate and contact wire uplift and strain at support by simulation when we use each tested wire as a messenger, and compared the results with the standard values that can realize stable current collection. Tables 3 and 4 show simulation conditions and standard values, respectively. Figure 3 shows the contact loss rate of the 2nd pantograph. As a result of the simulation, the contact loss rate of the 1st pantograph was set at 0 % for all wires and contact loss rates of the 2nd and 3rd pantographs became several percent at speeds higher than 180 km/h. However, the contact loss rate up to 160 km/h, which is practically the highest speed on narrow-gauge lines, is 0 %. Figures 4 and 5 show the contact wire uplift and strain at support, re-Table 3 Conditions of simulationTable 4 Standard values of current collecting characteristicsFig. 3 Simulation results (Contact loss rate)Fig.4 Simulation results (Contact wire strain at support)Fig. 5 Simulation results (Contact wire uplift at support) spectively. Either is not over the standard value up to the speed of 200 km/h with any wire.2.6 Examination resultsSince the current capacity, tensile strength and current collecting characteristics satisfied the standard values no matter which wire we use, we judged the appropriateness of the wires based on the wire resistance. Table 5 shows the judgment results. Under the condition of an 855 A current flow, we marked "O" if the wire resistance satisfies the judgment standard and "X" if not. Consequently, we reached a conclusion that use of PH730mm2 wire is appropriate with respect to the 855 A current capacity.Table 5 Judgment results3. Test by current collection testing equipmentThe current collection testing equipment of the Railway Technical Research Institute used for this test has a full length of 500 m and can carry out running tests up to the speed of 160 km/h, by using an actual contact wire and pantograph. We chose a PH730mm2 wire among the wires which were appropriate for the test in Chapter 2, constructed it as a messenger for the testing equipment, and examined its current collecting characteristics. Test conditions are as follows.3.1 Test conditions3.1.1 Basic composition of catenary and used pantographThe catenary of the testing equipment was composed to the specification shown in Table 6, which is used for narrow-gauge lines in Tokyo. This system has two PH356mm2 messenger wires and a GTM-SN170mm2 contact wire.Table 6 Test conditions3.1.2 Pantograph damperWe used a PS26 pantograph with a damper currently used for the limited express trains on narrow-gauge lines, and also examined the case where the damper is removed to assume common vehicles.Figure 6 shows the catenary composition and the measuring points of testing equipment.Fig. 6 Catenary composition and measuring points of current collection testing equipment3.2 Test resultsThe test results are shown in Figs. 7 to 9 when messenger tension is set at the standard value (39.2 kN). In these Figures, the results in the cases with and without pantograph dampers are compared.3.2.1 Contact loss rateFigure 7 shows the relation between speed and contact loss rate. In the case where there is a pantograph damper, it is 0.26 % at the speed of about 156 km/h. However, it is substantially less than the standard value of 5 %. In the case where there are no dampers, the contact loss is not generated up to about 150 km/h.3.2.2 Contact wire strainFigure 8 shows the relation between speed and con-tact wire strain at support. The allowable stress for oscillating fatigue of copper contact wire is set at 60 MPa based on the results of an experiment, or 500×10-6 when converted into strain. Since the strain in this experiment is considered as the difference between the maximum and minimum values, the standard value of contact wire strain is set at 1000 ×10-6 at the full amplitude. As it takes a maximum value at about 150 km/h, the value is 175 ×10-6 at the maximum, which is considerably less than the standard value of contact wire strain.Fig. 7 Test results (Contact loss rate)Fig. 8 Test results (Contact wire strain at support)Fig. 9 Test results (Contact wire uplift at support)3.2.3 Contact wire upliftFigure 9 shows the relation between speed and contact wire uplift at support. As it takes a maximum value of 10.8 mm at about 120 km/h, it is considerably to be less than the standard value of contact wire uplift at support.Figures 7 to 9 show the difference in the characteristics when a pantograph damper is used or not, we understand that the contact wire strain in the case where no dampersare used is a little smaller. Regarding other items, the current collecting characteristics are virtually not different from each other irrespective of whether a damper is used or not.3.3 Conclusion of the testWhen a PH730mm2 wire is selected and constructed to the standard tension of 39.2 kN as a messenger, the contact loss rate, contact wire strain and contact wire uplift at support satisfy the standard values. We understood that this system can be used up to 160 km/h. Moreover, when the pantograph damper is removed, it turns out that the current collecting characteristics do not change much or there are no problems in running. However, in the actual case where two or more pantographs are used, and the state of catenary is considered to be worse than on this testing equipment, the field running tests need to be performed for final judgment.4. ConclusionWe performed this research to investigate high-quality feeder messenger wire type overhead contact lines and examined a wire of copper system. We selected a PH730mm2 wire and used it as a messenger wire, and examined the current collecting characteristics at the speed up to 160 km/h by using current collection testing equipment. Although this system has a heavy large-diameter wire and may require difficult construction work, no important problems were experienced in the construction of the test equipment. It is required, however, to investigate the problems that will arise in the construction work on actual railway lines in service. References1)Shimodaira, Y.: "Study on messenger wire of wire type overhead contact line," Nationalconvention of I.E.E. JAPAN (in Japanese), 5-212, 1999.2）Iwainaka, A., Suzuki, A.: "Current collecting characteristics of one line copper feeder messenger wire type over head contact line," J-RAIL'99 (in Japanese), pp.265, 1999.From:QR Of RTRI ,Vol.44,No.2,May.2003译文:接触网承力索馈线与支线接触网的发展滨田孝弘研究员岩井淳纳卡前研究员电源技术科接触网结构部支线接触网导线以其节省劳力与维修费用的优点引起了人们的关注。
毕业设计英文翻译(译文)
编号：毕业设计(论文)外文翻译（译文）院（系）：桂林电子科技大学专业：电子信息工程学生姓名： xx学号： xxxxxxxxxx指导教师单位：桂林电子科技大学姓名： xxxx职称： xx2014年x月xx日定时通断电源用途开关电源产品广泛应用于工业自动化控制、军工设备、科研设备、LED照明、工控设备、通讯设备、电力设备、仪器仪表、医疗设备、半导体制冷制热、空气净化器，电子冰箱，液晶显示器，LED灯具，通讯设备，视听产品，安防，电脑机箱，数码产品和仪器类等领域。
简介随着电力电子技术的高速发展，电力电子设备与人们的工作、生活的关系日益密切，而电子设备都离不开可靠的电源，进入80年代计算机电源全面实现了开关电源化，率先完成计算机的电源换代，进入90年代开关电源相继进入各种电子、电器设备领域，程控交换机、通讯、电子检测设备电源、控制设备电源等都已广泛地使用了开关电源，更促进了开关电源技术的迅速发展。
开关电源是利用现代电力电子技术，控制开关晶体管开通和关断的时间比率，维持稳定输出电压的一种电源，开关电源一般由脉冲宽度调制（PWM）控制IC和开关器件（MOSFET、BJT等）构成。
开关电源和线性电源相比，二者的成本都随着输出功率的增加而增长，但二者增长速率各异。
线性电源成本在某一输出功率点上，反而高于开关电源。
随着电力电子技术的发展和创新，使得开关电源技术在不断地创新，这一成本反转点日益向低输出电力端移动，这为开关电源提供了广泛的发展空间。
开关电源高频化是其发展的方向，高频化使开关电源小型化，并使开关电源进入更广泛的应用领域，特别是在高新技术领域的应用，推动了高新技术产品的小型化、轻便化。
另外开关电源的发展与应用在节约能源、节约资源及保护环境方面都具有重要的意义。
分类现代开关电源有两种：一种是直流开关电源；另一种是交流开关电源。
这里主要介绍的只是直流开关电源，其功能是将电能质量较差的原生态电源（粗电），如市电电源或蓄电池电源，转换成满足设备要求的质量较高的直流电压（精电）。
电气化铁道技术接触网毕业论文中英文资料外文翻译文献
电气化铁道技术接触网毕业论文中英文资料外文翻译文献附录1 外文资料翻译A1.1 译文铁路系统接触网中集电板碳合金的含量对其与接触线磨影响本文主要是对发生在接触网中接触线和集电板之间磨损情况的研究，它们之间的磨损由机械和电气两个方面引起。
这方面的研究对设施的维修成本和受电弓与接触线的工作寿命有着密切的关系。
由于接触网中维修机车和基础设施方面的重要性，在过去几十年世界上一直对这个问题十分重视。
为了探讨机械和电气两方面引起的接触线和滑板之间的磨损，在米兰设计并安装了一种新型的测试装置。
一系列的实验测试已经完成，其中涉及了多种材料的集电板和在不同转速与电流强度的接触条件。
研究中涉及到了3kV直流线路所需要的各种不同结构的集电板。
研究中发现集电板中的铜和碳合金的不同含量对滑板与接触线的磨损有着很大的影响。
前言高速铁路运输系统的发展意味着对电能需求的增加，但是从目前通过受电弓在架空线（接触网）获取电能的水平来看，就需要受电弓集电板具有较高的工作性能。
这个问题不仅仅由于高速列车的原因，而且与线路的容量和货运列车的长期运行有关。
意大利铁路系统决定把所有的铜材料的集电板换为Kasperowski型，随后又把碳合金用于集电板，这些在线路材料方面的改进都是对3kv直流线路的挑战。
当接触线上的电流达到1000A以上时就会由于产生的机械热加重受电弓集电板的损坏。
众所周知，接触线和受电弓集电板的磨损主要取决于以下几个因素：接触线材料的类型，运行条件（滑动速度接触力电流强度等）以及它们之间是否发出电火花和电弧等。
在Klapas et al.和Becker的的著作中，对以上提到的决定线路磨损程度的各种原因以及它们之间的相互影响都有说明。
基于简单方便起见，在集电板和接触线之间产生的磨损可以分为两种：一种是由于机械摩擦引起的磨损，另外一种是由于电火花引起的磨损，这两者相互作用并影响。
特别是越来越多的磨损不仅和线路的电流强度有关，而且和弓网之间的接触压力有关，同时和火花强度有关的磨损也随着接触压力的增大而加重。
毕业设计英文文献翻译(电力方向附带中文)
毕业设计英文文献翻译(电力方向附带中文)大学毕业设计英文文献翻译,关于电力系统方向,电力谐波!绝对原创!HarmonicsService reliability and quality of power have become growing concerns for many facility managers, especially with the increasing sensitivity of electronic equipment and automated controls. There are several types of voltage fluctuations that can cause problems, including surges and spikes, sags, harmonic distortion, and momentary disruptions. Harmonics can cause sensitive equipment to malfunction and other problems, including overheating of transformers and wiring, nuisance breaker trips, and reduced power factor.What Are Harmonics?Harmonics are voltage and current frequencies riding on top of the normal sinusoidal voltage and current waveforms. Usually these harmonic frequencies are in multiples of the fundamental frequency, which is 60 hertz (Hz) in the US and Canada. The mostcommon source of harmonic distortion is electronic equipment using switch-mode power supplies, such as computers, adjustable-speed drives, and high-efficiency electronic light ballasts.Harmonics are created by these Dswitching loads‖ (also called “nonlinear loads,‖ because current does not vary smoothly with voltage as it does with simple resistive and reactive loads): Each time the current is switched on and off, a current pulse is created. The resulting pulsed waveform is made up of a spectrum of harmonic frequencies, including the 60 Hz fundamental and multiples of it. This voltage distortion typically results from distortion in the current reacting with system impedance. (Impedance is a measure of the total opposi tion―resistance, capacitance, and inductance―to the flow of an alternating current.) The higher-frequency waveforms, collectively referred to as total harmonic distortion (THD), perform no useful work and can be asignificant nuisance.Harmonic waveforms are characterized by their amplitude and harmonic number. In the U.S. and Canada, the third harmonic is 180 Hz―or 3 x 60 Hz―and the fifth harmonic is 300 Hz (5 x 60Hz). The third harmonic (and multiples of it) is the largest problem in circuits with single-phase loads such as computers and fax machines. Figure 1 shows how the 60-Hz alternating current (AC) voltage waveform changes when harmonics are added.大学毕业设计英文文献翻译,关于电力系统方向,电力谐波!绝对原创!The Problem with HarmonicsAny distribution circuit serving modern electronic devices will contain some degree of harmonic frequencies. The harmonics do not always cause problems, but the greater the power drawn by these modern devices or other nonlinear loads, the greater the level of voltage distortion. Potential problems (or symptoms of problems) attributed to harmonics include:■ Malfunction of sensitive equipment■ Random tripping of circuit breakers■ Flickering lights■ Very high neutral currents■ Overheated phase conductors, panels, and transformers ■ Premature failure of transformers and uninterruptible power supplies (UPSs)■ Reduced power factor■ Reduced system capacity (because harmonics create additional heat, transformers and otherdistribution equipment cannot carry full rated load)Identifying the ProblemWithout obvious symptoms such as nuisance breaker trips or overheated transformers, how do you determine whether harmonic current or voltages are a cause for concern? Here are several suggestions for simple, inexpensive measurements that a facility manager or staff electrician could take, starting at the outlet and moving upstream:■ Measure the peak and root mean square (RMS) voltage at a sample of receptacles. The Dcrest factor‖ is the ra tio of peak to RMS voltage. For a perfectly sinusoidal voltage, the crest factor will be 1.4. Low crest factor is a clear indicator of the presence of harmonics. Note that these measurements must be performed with a Dtrue RMS‖ meter―one that doesn‘t assume a perfectly sinusoidal waveform.■ Inspect distribution panels. Remove panel covers and visually inspect components for signs of overheating, including discolored or receded insulation or discoloration of terminal screws. If you see any of these symptoms, check that connectionsare tight (since loose connections could also cause overheating), and compare currents in all conductors to their ratings.■ Measure phase and neutral currents at the transformer secondary with clamp-on current probes. If no harmonics are being generated, the neutral current of a three-phase distribution system carries only the imbalance of the phase currents. In a well-balanced three-phase distribution system, phase currents will be very similar, and current in the neutral conductor should be much lower than phase current and far below its rated current capacity. If phase currents are similar and neutral current exceeds their imbalance by a wide margin, harmonics are present. If neutral current is above 70 percent of the cond uctor‘s rated capacity, you need to mitigate the problem.■Compare transformer temperature and loading with nameplate temperature rise and capacity ratings. Even lightly loaded transformers can overheat if harmonic current is high. A transformer that is near or over its rated temperature rise but is loaded well below its rated capacity is a clear sign that harmonics are at work. (Many transformers have built-in temperature gauges. If yours does not, infrared thermography can be used to detect overheating.)大学毕业设计英文文献翻译,关于电力系统方向,电力谐波!绝对原创!In addition to these simple measurements, many power-monitoring devices are now commercially available from a variety of manufacturers to measure and record harmonic levels. These instruments provide detailed information on THD, as well as on the intensity of individual harmonic frequencies. After taking the appropriate measurements to determine whether you have high levels of harmonics and, if so, to find the source, you will be well-positioned to choose the best solution.Solutions to Harmonics ProblemsThe best way to deal with harmonics problems is through prevention: choosing equipment and installation practices that minimize the level of harmonics in any one circuit or portion of a facility. Many power quality problems, including those resulting from harmonics, occur when new equipment is haphazardly added to older systems. However, even within existing facilities, the problems can often be solved with simple solutions such as fixing poor or nonexistent grounding on individual equipment or the facility as a whole, moving a few loads between branch circuits, or adding additional circuits to help isolate the sensitiveequipment from what is causing the harmonic distortion. If the problems cannot be solved by these simple measures, there are two basic choices: to reinforce the distribution system to withstand the harmonics or to install devices to attenuate or remove the harmonics. Reinforcing the distribution system means installing double-size neutral wires or installing separate neutral wires for each phase, and/or installing oversized or Krated transformers, which allow for more heat dissipation. There are also harmonic-rated circuit breakers and panels, which are designed to prevent overheating due to harmonics. This option is generally more suited to new facilities, because the costs of retrofitting an existing facility in this way could be significant. Strategies for attenuating harmonics, from cheap to more expensive, include passive harmonic filters, isolation transformers, harmonic mitigating transformers (HMTs), the Harmonic Suppression System (HSS) from Harmonics Ltd., and active filters(Table 1).Passive filters (also called traps) include devices that provide low-impedance paths to divert harmonics to ground and devices that create a higher-impedance path to discourage the flow of harmonics. Both of these devices, by necessity, change theimpedance characteristics of the circuits into which they are inserted. Another weakness of passive harmonic technologies is that, as their name implies, they cannot adapt to changes in the electrical systems in which they operate. This means that changes to the electrical system (for example, the addition or removal of power factorCcorrection capacitors or the addition of more nonlinear loads) could cause them to be overloaded or to create Dresonances‖ that could actually amplify, rather than diminish, harmonics.Active harmonic filters, in contrast, continuously adjust their behavior in response to the harmonic current content of the monitored circuit, and they will not cause resonance. Like an automatic transmission in a car, active filters are designed to accommodate a full range of expected operating conditions upon installation, without requiring further adjustments by the operator.Isolation transformers are filtering devices that segregate harmonics in the circuit in which they are created, protecting upstream equipment from the effects of harmonics. These transformers do not remove the problem in the circuit generating the harmonics, but they can prevent the harmonics from affecting more sensitive equipment elsewhere within the facility.大学毕业设计英文文献翻译,关于电力系统方向,电力谐波!绝对原创!Harmonic mitigating transformers actually do relieve problematic harmonics. HMTs can be quite cost-effective in the right application, because they can both improve reliability and reduce energy costs. The right application includes transformers that are heavily or moderately loaded and where high levels of harmonic currents are present. In addition, HMTs are very effective in supporting critical loads that are backed up by a UPS. UPSs and backup generators tend to have high impedance, which results in high voltage distortion under nonlinear loading. Because of this, equipment that operates flawlessly when supplied by utility power may malfunction when the backup system engages during a utility outage. Note that some of these power systems have output filters (either passive or active) to control harmonic levels. The presence or absence of such filters should be determined before adding an HMT.The Harmonics Ltd. Harmonic Suppression System is a unique solution for single-phase loads that is designed to suppress the third harmonic. An HSS is generally more expensive than an HMT, but it is designed to attenuate the harmonicsproblems throughout the entire distribution system, not just upstream of the transformer. The types of facilities that present the best opportunities for HSS installation are those that place a very high premium on power quality and reliability, such as server farms, radio and television broadcast studios, and hospitals. (See .) Economic EvaluationEvaluating the life-cycle costs and effectiveness of harmonics mitigation technologies can be ve ry challenging―beyond the expertise of most industrial facility managers. After performing the proper measurement and analysis of the harmonics problem, this type of evaluation requires an analysis of the costs of the harmonics problem (downtime of sensitive equipment, reduced power factor, energy losses or potential energy savings) and the costs of the solutions. A good place to start in performing this type of analysis is to ask your local utility or electricity provider for assistance. Many utilities offer their own power quality mitigation services or can refer you to outside power quality service providers.Additional ResourcesInstitute of Electrical and Electronics Engineers (IEEE),Standard 519-1992, DIEEE大学毕业设计英文文献翻译,关于电力系统方向,电力谐波!绝对原创!Recommended Practices and Requirements for Harmonic Control in Electric Power Systems‖ (1992), available at .Relationship between harmonics and symmetrical componentsAbstract New terminology is introduced to make clear the relationship between harmonics and symmetrical components. Three-phase sets are classified in terms of symmetrical sets and asymmetrical sets. Subclasses are introduced with the names symmetrical balanced sets, symmetrical unbalanced sets, asymmetrical balanced sets and asymmetrical unbalanced sets to show that a threephase set can resolve to either one, two or three symmetrical component sets. The results from four case studies show that these subclasses and their resolution to symmetrical component sets improve understanding of harmonic analysis of systems having balanced and unbalanced harmonic sources and loads.Keywords asymmetrical sets; harmonic flows; harmonic sources; symmetrical component sets; symmetrical sets Any periodic wave shape can be broken down into oranalysed as a fundamentalwave and a series of harmonics.Three-phase harmonic analysis requires a clear understanding of the relationship between symmetrical component injections from harmonic sources (e.g. adjustable speed drives, ASDs) and their relationship to harmonic flows (symmetrical components) arising from the application of a harmonic source to a linear system.Alimited number of references contain brief information concerning harmonics and symmetrical components. Reference 1, provides a paragraph on this topic and uses the heading Relationship between Harmonics and Symmetrical Components‘.It includes a table that is supported by a brief explanatory paragraph. The table expresses harmonics in terms of positive, negative and zero sequences. It states that these sequences are for harmonics in balanced three-phase systems. The heading refers to symmetrical components while the content refers to balanced three-phase systems. Herein lies the anomaly. Classically, symmetrical components (especially ero sequence) are only applied in unbalanced systems. The following questions rose after reading the Ref. 1 paragraph.(a)Do symmetrical components (especially zero sequence), in the classical sense,apply in balanced as well as unbalanced non-sinusoidal systems and is this abreak from tradition?(b)What do the terms, symmetrical, asymmetrical, balanced, unbalanced andsymmetrical components mean?(c)What are the conditions under which a system must operate so that harmonicsresolve to positive, negative and zero sequences and is the table given inRef. 1 correct?The terminology used is found inadequate for describing non-sinusoidal systems.There is thus a need to introduce a three-phase terminology that will show the relationship and make the comparison between injections (currents) and harmonic flows (voltages and currents) meaningful.References 3 provides the basis for the solution by providing definitions for threephase sets‘, symmetrical sets‘an d symmetricalcomponent sets‘.The purpose of this paper is to introduce an approach to harmonic analysis大学毕业设计英文文献翻译,关于电力系统方向,电力谐波!绝对原创!based on the classification of three-phase sets and to make to comparison between injections from harmonic sources and corresponding harmonic flows quantifiable by expressing the results in terms of the number of symmetrical component sets found.Harmonic flows and their resolution to symmetrical components depends upon the magnitudes and phase sequences of the injections from a harmonic source, on the system‘s sequence impedances, on three- and four-wire connections and on whether the customer‘s linear load on the system is balanced or unbalanced. Therefore, what is injected in terms of symmetrical component sets by a harmonic source is not necessarily received by the system, i.e. the harmonic flows may resolve to one, two or three symmetrical component sets and this depends upon the type of three-phase set found. Therefore, any three-phase harmonic may be partially made up of any of thesymmetrical component sets.Four case studies are reported and they show a novel method for teaching the flow of power system harmonics. It is important to use case studies as part of one‘s teaching as they link learning to concepts and improve understanding. They show how the method of symmetrical components can be extended to a system‘s response to harmonic flows. When taught as a group, the four case studies improve cognitive skills by showing that the symmetrical component responses under unbalanced situations are different to the balanced state.IEEE __TIONS ON POWER __NICS VOL.19,NO.3,__年大学毕业设计英文文献翻译,关于电力系统方向,电力谐波!绝对原创!谐波服务的可靠性和电能质量已成为越来越多设施经理的关注，尤其是随着电子设备和自动化控制灵敏度提高了很多。
接触网自我鉴定
接触网自我鉴定英文回答：As an Assistant Engineer in the Contact Network department, I have been responsible for a wide range of tasks, including the design, installation, and maintenance of overhead contact systems for electric railways and tramways. I have a strong understanding of the principles of electrical engineering, as well as the practical aspects of contact network construction and repair.One of my key responsibilities is to carry out regular inspections of the contact network to ensure that it is in good working order and compliant with safety regulations. I use a variety of tools and techniques to inspect the contact wire, insulators, and supporting structures, and I am able to identify any potential hazards or areas of concern. If I find any issues, I am responsible for taking the necessary steps to rectify them, such as replacing damaged components or tightening loose connections.In addition to my inspection work, I am also involvedin the design and installation of new contact network systems. I work closely with other engineers and technicians to develop plans for new installations, and I am responsible for overseeing the construction and commissioning of the new systems. I also provide training to other staff on the operation and maintenance of contact network systems.I am a highly motivated and results-oriented individual with a strong commitment to safety. I am always looking for ways to improve my knowledge and skills, and I am eager to take on new challenges. I am confident that I can make a significant contribution to any organization that I work for.中文回答：作为接触网部门的一名助理工程师，我负责广泛的任务，包括设计、安装和维护铁路和有轨电车的接触网系统。
接触网工发言稿
接触网工发言稿英文回答：Thank you for the kind introduction. It is a greathonor to be here today to speak to such a distinguished audience. I am grateful for the opportunity to share my thoughts on the topic of grid modernization.As you know, the electric grid is a critical piece of infrastructure that powers our lives. It deliverselectricity to our homes, businesses, and schools. It also keeps our hospitals running and our traffic lights blinking.The grid is constantly evolving to meet the changing needs of our society. In the past, the grid was designed to deliver electricity from large, centralized power plants to consumers. Today, the grid is becoming more decentralized, with more renewable energy sources and distributed generation.This transition to a more modern grid is driven by a number of factors, including the need to reduce carbon emissions, the rising cost of fossil fuels, and the increasing demand for electricity.Grid modernization is a complex and challenging undertaking. It requires a coordinated effort from all stakeholders, including utilities, regulators, and consumers.One of the key challenges of grid modernization is the need to integrate more renewable energy sources into the grid. Renewable energy sources, such as solar and wind power, are intermittent and variable. This means that the grid must be able to accommodate fluctuations in the supply of electricity from these sources.Another challenge of grid modernization is the need to improve the resilience of the grid. The grid is vulnerable to a variety of threats, including extreme weather events, cyber attacks, and physical attacks. Grid modernization efforts must focus on making the grid more resilient tothese threats.Grid modernization is a critical investment in our future. It will help us to reduce carbon emissions, save money on energy costs, and improve the reliability of the grid.I am confident that we can meet the challenges of grid modernization and build a more modern, resilient, and sustainable grid for the future.中文回答：很荣幸今天能够在这里与大家讨论电网现代化的话题。
接触网工技术总结范文
接触网工技术总结范文英文回答：Introduction:In today's rapidly evolving world, the internet has become an integral part of our lives. As a result, network engineering has gained immense significance. In this summary, I will discuss my experience and knowledge of working with web technologies, specifically focusing on contact networks.Background:Contact networks, also known as touch networks, are a crucial aspect of web engineering. They enable the exchange of data and information between different entities within a network. These networks play a pivotal role in various domains, such as social media platforms, e-commerce websites, and online gaming platforms.Working with Contact Networks:During my work with contact networks, I have gained expertise in several key areas. Firstly, I have developed a deep understanding of network protocols, such as TCP/IP, HTTP, and DNS. These protocols facilitate the seamless transfer of data packets across the network.Moreover, I have honed my skills in network security.It is essential to ensure the confidentiality, integrity, and availability of data in contact networks. I have implemented various security measures, including firewalls, encryption techniques, and intrusion detection systems, to safeguard the network from potential threats.Furthermore, I have acquired proficiency in load balancing and scalability. Contact networks oftenexperience heavy traffic, especially during peak hours. By implementing load balancing techniques, such as round-robin or least-connection algorithms, I have successfully distributed the network load evenly across multiple servers.This ensures optimal performance and prevents server overloading.Additionally, I have worked extensively with content delivery networks (CDNs). CDNs are used to deliver web content to users based on their geographical location, reducing latency and improving user experience. By strategically deploying CDN servers worldwide, I have enhanced the speed and availability of web content for users across the globe.Conclusion:In conclusion, my experience with contact networks has provided me with a comprehensive understanding of network protocols, security measures, load balancing, and content delivery networks. These skills have enabled me to effectively design, implement, and maintain contact networks that are secure, scalable, and efficient. I look forward to further expanding my knowledge and expertise in this field.中文回答：简介：在当今快速发展的世界中，互联网已成为我们生活的重要组成部分。
简单链型悬挂AT方式接触网设计——毕业设计 精品
简单链型悬挂AT方式接触网设计Design of Overhead Contact System in Single Catenary System with AT Way摘要电气化铁路因其运输能力强、运营成本低、能源消耗少和环境污染小等优点，受到世界各国的普遍重视，成为了当今铁路的发展方向。
而接触网作为电气化铁路的重要组成部分，其状态的优劣直接影响到电气化铁路的运行安全。
因此，合理的接触网设计，能够提高接触网系统的可靠性，保证铁路生产的正常运行。
接触网设计特别是高速接触网设计过程包含了大量的设计计算、绘图、校验等工作。
为了减少接触网设计人员的工作负担，缩短设计周期，提高设计质量，保证电气化铁路运行的安全性和可靠性，使用计算机辅助设计是非常必要的。
本次设计就是采用AutoCAD为制图工具，依据相应的计算结果、设计手册和气象条件等对区间进行相关的跨距的选择，吊弦的设计，补偿装置的选取，锚段关节的选用，支柱布置和类型选取等。
关键词：电气化铁路接触网设计简单链型悬挂AT方式AbstractWith its advantages of stronger transport capacity, lower operating costs, less energy consumption, smaller environmental pollution and so on, the electrified railway is universally concerned and has became the railway development orientation. The overhead contact system, as one of the most important components in the electrified railway, its state has been taking great effects on the safe operating of the electrified railway. Therefore, reasonable design can improve reliability of the system, to ensure that the electrified railway would operate safely.Design of catenary especially for high-speed consists of a lot of design calculations, drawings, checking and so on.To reduce the work of designers of catenary, shorten the time of design cycle, improve design quality,ensure safety and reliability of the electrified railway operation, using computer-aided design is very necessary. This design is the use of AutoCAD as a drawing tool, based on the corresponding calculations, design manual and meteorological conditions for the associated section design about the selection of the span, the dropper, the compensation device , the overlap span,the mast and so on.Key words: electrified railway design of the overhead contact systemsingle catenary system autotransformer way目录第1章绪论 (1)1.1 课题研究的目的意义 (1)1.2 国内外发展现状 (1)1.3 设计的目的及主要任务 (1)第2章牵引网简介 (3)2.1 牵引网供电方式 (3)2.2 接触网简介 (3)2.2.1 接触悬挂及类型 (4)2.2.2 支持装置 (5)2.2.3 定位装置 (6)2.2.4 支柱与基础 (6)2.3 接触网的特点及要求 (6)第3章区间接触网设计 (7)3.1 气象条件的确定 (7)3.2 计算负载的确定 (7)3.2.1 线索自重负载 (7)3.2.2 覆冰负载 (8)3.2.3 风负载 (9)3.2.4 合成负载 (10)3.3 支柱负载的计算 (11)3.3.1 垂直负载 (11)3.3.2 水平负载 (12)3.4 设备选择 (13)3.4.1 线索的选取 (13)3.4.2 腕臂的选取 (14)3.4.3 定位装置的选用 (15)3.4.4 支柱及基础 (16)3.5 设计参数 (18)3.5.1 接触线高度和结构高度的选取 (18)3.5.2 跨距的选择 (18)3.5.3 拉出值选用 (19)3.5.4 侧面限界选用 (19)3.5.5 支柱类型 (19)3.6 参数校验 (20)3.6.1 最大允许跨距的确定 (20)3.6.2 锚段长度的校验计算 (20)3.6.3 支柱容量校验 (21)第4章吊弦计算 (24)4.1 基本条件分析 (24)4.2 参数说明 (24)4.3 计算内容 (25)第5章锚段及锚段关节 (27)5.1 锚段的划分 (27)5.2 锚段关节 (28)5.2.1 五跨绝缘锚段关节 (28)5.2.2 七跨电分相锚段关节 (29)第6章补偿装置的选取 (30)6.1 补偿装置方案的选择 (30)6.2 补偿装置的计算 (31)第7章结论与展望 (33)7.1 结论 (33)7.2 展望 (33)参考文献 (34)致谢 ..................................................................................................... 错误！未定义书签。
(完整版)接触网英文翻译英文毕业设计论文
Development of Feeder Messenger Wire Type OverheadContact Line with One Copper Messenger Wire Takahiro HAMADA Atsushi IWAINAKAResearcher, Former Researcher,Contact Line Structures, Power Supply Technology Div.Feeder messenger wire type overhead contact lines attention recently from the viewpoint of labor-saving for maintenance. A type that uses two PH356mm2messenger wires was introduced into the Tokyo district, while another that uses an SBTACSR730mm2messenger wire into the Kansai district. In terms of the number of messenger wires, the one-wire type is more useful, as it involves a smaller number of parts. As the material for the wire, copper is better than aluminum, since it does not require connection with different metals. To realize the advantages of the two systems, therefore, we developed a feeder messenger wire type overhead contact line that Feeder messenger wire type overhead contact lines of feeder with the messenger wire. They attention recently in Japan from the viewpoint of labor-saving for maintenance. They use two copper stranded conductorPH356mm2messenger wires in the Tokyo district and an aluminum conductor steel-reinforced SBTACSR730mm2 messenger wire in the Kansai district. In terms of the number of messenger wires, the one-wire type is more useful as it involves a smaller number of parts, and copper is better as the material for the wire than aluminum since it does not require connection with different metals. Therefore, we promoted this research for the purpose of developing a feeder messenger wire type overhead contact line that order to determine what wires suit the new overhead contact line, we chose a narrow-gauge line in Tokyo as a test site, studied whether electrical and mechanical characteristics of wires satisfy the standard values, and examined the current collecting characteristics of various types of wires through simulation. As a result, it was proved that the PH730mm2 messenger wire was the most appropriate in the overcrowded railway sections in Tokyo.Based on this result, we actually constructed a PH730mm2 messenger wire and investigated its current collecting characteristics by using current collection testing equipment to find that standard values were all satisfied at the speed of 160km at speeds up to 160km of the optimum wires Table 1 lists the wires examined as candidates of one messenger wire. We examined the current capacity, wire resistance, tensile strength, minimum the narrow-gauge lines in Tokyo. A comparison of the resistance of two PH356mm2 wires with that of test wires at 20℃(shaded bar), proves that the resistance of THDC670mm2 wire and PH670mm2 wire is that of two PH356mm2wires. Moreover, in the case of the resistance after temperature rise (slash), only the resistance of THDC670mm2wire and PH670mm2 wire is that of two PH356mm2 wires.2.2 Tensile strengthSince it is assumed that this catenary system is constructed to astandard tension of 39.2kN, it is a condition that the tensile strength is set at over 86.24kN, as the safety factor of copper is 2.2 in Japan. All the tensile strengths for the test wires referred to in this paper are over 86.24kN.2.3 Minimum the assumption that the messenger wire tension is 39.2kN; contact wire tension is 14.7kN; and span length is 50m. When we assume a standard system Tokyo, only the minimum 150mm. If the system 150mm.2.4 Current collecting characteristicsWe calculated the contact loss rate and contact wire uplift and strain at support by simulation when we use each tested wire as a messenger, and compared the results with the standard values that can realize stable current collection. Tables 2 show simulation conditions and standard values, respectively. As a result of the simulation, the contact loss rate of the 1st pantograph was set at 0% for all wires and contact loss rates of the 2nd and 3rd pantographs became several percent at speeds 180km narrow-gauge lines, is 0%. Either is not over the standard value up to the speed of 200km2.5 Examination resultsSince the current capacity, tensile strength and current collecting characteristics satisfied the standard values no matter which wire we use,we judged the appropriateness of the wires based on the wire resistance. Table 3 shows the judgment results. Under the condition of an 855A current flow, we marked "O" if the wire resistance satisfies the judgment standard and "X" if not. Consequently, we reached a conclusion that use of PH730mm2 wire is appropriate with respect to the 855A current capacity.Table 3 Judgment results3. ConclusionWe performed this research to investigate testing equipment. Although this system work, no important problems were experienced in the construction of the test equipment. It is required, the construction work on actual railway lines in service.References1)Shimodaira, Y.: "Study on messenger wire of wire type overhead contact line,"National convention of I.E.E. JAPAN (in Japanese), 5-212, 1999.2）Iwainaka, A., Suzuki, A.: "Current collecting characteristics of one line copper feeder messenger wire type over Japanese), pp.265, 1999. From:QR Of RTRI ,Vol.44,No.2,May.2003。
接触网自我鉴定
接触网自我鉴定英文回答：As a professional in the field of contact networks, I have a deep understanding of the design, implementation, and maintenance of electrical infrastructure systems that power railways and urban transit systems.My expertise encompasses a thorough knowledge of catenary systems, including the principles of overhead line construction, tensioning, and insulation. I possess strong analytical and problem-solving skills, enabling me to identify and resolve issues related to power supply, voltage regulation, and interference.In my previous role at [Company Name], I played a pivotal role in the development and implementation of a new contact network system for a high-speed rail line. My responsibilities included:Conducting feasibility studies to determine the optimal network design。
Designing and specifying catenary components, including masts, insulators, and conductors。
接触网自我鉴定
接触网自我鉴定英文回答：Self-Assessment: Electrified Railway Contact System。
My expertise in electrified railway contact systems has been honed through years of practical experience and academic inquiry. I possess a comprehensive understanding of the design, installation, maintenance, and troubleshooting of overhead contact systems (OCS).My proficiency in OCS design includes meticulous planning and analysis to optimize current collection efficiency, minimize downtime, and ensure system longevity.I have employed advanced engineering software to model and simulate OCS configurations, ensuring their compatibility with specific railway infrastructure and operational requirements.As a seasoned installer, I have supervised andparticipated in numerous OCS installation projects. My meticulous attention to detail and adherence to safety protocols have consistently resulted in high-quality installations that meet the most stringent industry standards. I have also developed innovative techniques to streamline the installation process, reducing both time and costs without compromising safety or performance.Maintenance plays a pivotal role in ensuring the reliability and efficiency of OCS. I have extensive experience in developing and implementing comprehensive maintenance plans, tailored to the specific needs of each system. My proactive approach to maintenance has minimized unscheduled outages and extended the lifespan of OCS assets.Furthermore, my strong analytical skills enable me to effectively troubleshoot and resolve OCS issues. I am adept at interpreting data from monitoring systems and utilizing diagnostic techniques to identify and rectify faultsquickly and efficiently. My experience in collaboratingwith cross-functional teams has allowed me to effectively manage and coordinate complex repair and maintenanceoperations.My passion for continuous learning has led me toactively participate in industry conferences and seminars, staying abreast of the latest advancements in OCStechnology and best practices. I am also committed to sharing my knowledge through technical publications and presentations, contributing to the advancement of the field.In summary, my exceptional expertise in electrified railway contact systems encompasses a deep understanding of design, installation, maintenance, and troubleshooting. My proven ability to deliver high-quality solutions, coupled with my unwavering commitment to safety and efficiency, makes me a valuable asset to any organization seeking to optimize its railway infrastructure.中文回答：接触网自我鉴定。
铁路接触网工面试自我介绍
铁路接触网工面试自我介绍**英文部分**Good morning, I am delighted to have the opportunity to introduce myself for the position of Railway Contact Network Engineer. My name is [Your Name], and I possess a solid background in electrical engineering, specializing in railway systems.Throughout my academic journey, I have gained extensive knowledge in the field of railway contact networks, covering areas such as design, installation, maintenance, and troubleshooting. My thesis project focused on optimizing the efficiency of contact networks in high-speed rail systems, which allowed me to delve deeply into the intricacies of the subject.Professionally, I have worked on several railway projects, both domestically and internationally. My experience includes working on the installation of contact networks for new railway lines, as well as conducting routine maintenance and emergency repairs on existing ones. I am proficient in using specialized tools and equipment, and I am always keen to learn new techniques and technologies to enhance my skills.I pride myself on my ability to work independently as well as collaboratively. I have excellent communication skills, which have enabled me to effectively coordinate with multidisciplinary teamsto ensure the smooth operation of railway systems. Additionally, I am committed to safety, adhering strictly to all regulations and procedures to ensure the safety of both personnel and the railway infrastructure.In conclusion, I am confident that my qualifications and experiences align well with the requirements of this position. I am eager to contribute my expertise to your team and help in maintaining the efficiency and safety of railway contact networks.**中文翻译部分**早上好，非常荣幸有机会参加铁路接触网工程师的面试。
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Development of Feeder Messenger Wire Type OverheadContact Line with One Copper Messenger Wire Takahiro HAMADA Atsushi IWAINAKAResearcher, Former Researcher,Contact Line Structures, Power Supply Technology Div.Feeder messenger wire type overhead contact lines attention recently from the viewpoint of labor-saving for maintenance. A type that uses two PH356mm2messenger wires was introduced into the Tokyo district, while another that uses an SBTACSR730mm2messenger wire into the Kansai district. In terms of the number of messenger wires, the one-wire type is more useful, as it involves a smaller number of parts. As the material for the wire, copper is better than aluminum, since it does not require connection with different metals. To realize the advantages of the two systems, therefore, we developed a feeder messenger wire type overhead contact line that Feeder messenger wire type overhead contact lines of feeder with the messenger wire. They attention recently in Japan from the viewpoint of labor-saving for maintenance. They use two copper stranded conductorPH356mm2messenger wires in the Tokyo district and an aluminum conductor steel-reinforced SBTACSR730mm2 messenger wire in the Kansai district. In terms of the number of messenger wires, the one-wire type is more useful as it involves a smaller number of parts, and copper is better as the material for the wire than aluminum since it does not require connection with different metals. Therefore, we promoted this research for the purpose of developing a feeder messenger wire type overhead contact line that order to determine what wires suit the new overhead contact line, we chose a narrow-gauge line in Tokyo as a test site, studied whether electrical and mechanical characteristics of wires satisfy the standard values, and examined the current collecting characteristics of various types of wires through simulation. As a result, it was proved that the PH730mm2 messenger wire was the most appropriate in the overcrowded railway sections in Tokyo.Based on this result, we actually constructed a PH730mm2 messenger wire and investigated its current collecting characteristics by using current collection testing equipment to find that standard values were all satisfied at the speed of 160km at speeds up to 160km of the optimum wires Table 1 lists the wires examined as candidates of one messenger wire. We examined the current capacity, wire resistance, tensile strength, minimum the narrow-gauge lines in Tokyo. A comparison of the resistance of two PH356mm2 wires with that of test wires at 20℃(shaded bar), proves that the resistance of THDC670mm2 wire and PH670mm2 wire is that of two PH356mm2wires. Moreover, in the case of the resistance after temperature rise (slash), only the resistance of THDC670mm2wire and PH670mm2 wire is that of two PH356mm2 wires.2.2 Tensile strengthSince it is assumed that this catenary system is constructed to astandard tension of 39.2kN, it is a condition that the tensile strength is set at over 86.24kN, as the safety factor of copper is 2.2 in Japan. All the tensile strengths for the test wires referred to in this paper are over 86.24kN.2.3 Minimum the assumption that the messenger wire tension is 39.2kN; contact wire tension is 14.7kN; and span length is 50m. When we assume a standard system Tokyo, only the minimum 150mm. If the system 150mm.2.4 Current collecting characteristicsWe calculated the contact loss rate and contact wire uplift and strain at support by simulation when we use each tested wire as a messenger, and compared the results with the standard values that can realize stable current collection. Tables 2 show simulation conditions and standard values, respectively. As a result of the simulation, the contact loss rate of the 1st pantograph was set at 0% for all wires and contact loss rates of the 2nd and 3rd pantographs became several percent at speeds 180km narrow-gauge lines, is 0%. Either is not over the standard value up to the speed of 200km2.5 Examination resultsSince the current capacity, tensile strength and current collecting characteristics satisfied the standard values no matter which wire we use,we judged the appropriateness of the wires based on the wire resistance. Table 3 shows the judgment results. Under the condition of an 855A current flow, we marked "O" if the wire resistance satisfies the judgment standard and "X" if not. Consequently, we reached a conclusion that use of PH730mm2 wire is appropriate with respect to the 855A current capacity.Table 3 Judgment results3. ConclusionWe performed this research to investigate testing equipment. Although this system work, no important problems were experienced in the construction of the test equipment. It is required, the construction work on actual railway lines in service.References1)Shimodaira, Y.: "Study on messenger wire of wire type overhead contact line,"National convention of I.E.E. JAPAN (in Japanese), 5-212, 1999.2）Iwainaka, A., Suzuki, A.: "Current collecting characteristics of one line copper feeder messenger wire type over Japanese), pp.265, 1999. From:QR Of RTRI ,Vol.44,No.2,May.2003。