外文翻译预测铁路供电系统工作模式的方法和工具_第1页
外文翻译预测铁路供电系统工作模式的方法和工具_第2页
外文翻译预测铁路供电系统工作模式的方法和工具_第3页
外文翻译预测铁路供电系统工作模式的方法和工具_第4页
外文翻译预测铁路供电系统工作模式的方法和工具_第5页
已阅读5页,还剩15页未读 继续免费阅读

下载本文档

版权说明:本文档由用户提供并上传,收益归属内容提供方,若内容存在侵权,请进行举报或认领

文档简介

1、railway condition monitoring,2006. the institution of engineering and technology international conference on29-30 nov.2006 page(s):63-66iee cnfmethods and tools for predicting working modes of railroad power-supply systemszaytseva, l.a.; zaytsev, v.v.rostov state university of transport communicatio

2、ns, lenin street, 44/6, apt. 23, 344038 rostov-on-don, russiatvadimcs.vu.nl, fax: +31(20)5987653keywords: power supply, electrification, breakdown mode, modelling.abstractthis research is dedicated to design and implementation of a computer application for predicting the functioning of a railway pow

3、er supply system (both on developing stage and in operational state). the process of creating a model for simulation of train movements is described in detail. two working modes are considered in required hardware reliability estimation: a normal mode (standard conditions) and a breakdown mode (when

4、 one of the substations is down). model analysis and implementation of the results obtained show their trustworthiness. while exploring model behaviour, we could determine minimum time interval between trains, estimate maximum possible current, voltage losses, as well as other parameters.1 introduct

5、ionduring the last decade railway electrification was a hot topic in russia. a lot of attention has been paid to economic efficiency of the solutions proposed for newly electrified zones. total cost of ownership should be as low as possible without hindering reliability, requirements for which alway

6、s remain high.in order to make the best choice in railway power supply, usually several variants are examined. the most economic and considerably reliable one is chosen for deployment. computer model can be used to predict how the real power supply system will work. such a model is considered in the

7、 following sections of the paper.the model should simulate train movements and power supply system behaviour in several admission modes for trains, as close as possible. by admission mode two parameters are basically meant here: time interval (or gap)between trains and train grouping and positioning

8、.the most difficult type of problem is modelling train movements on single track railway section. it is quite common on single track sections to let several trains going in one direction run together in one pack (with a fixed gap in between), and only then let the trains go in the other direction. t

9、he time interval between trains inside such a pack can be minimal, which leads to load increase for the tractionnetwork. a computer model allows for predicting power supply system working conditions with any train positioning on a single track railway section.the working modes of a power supply syst

10、em depend also on a feeding scheme of a particular section. the primary mode on a single track section is feeding from both sides. with such a scheme, two adjacent railway substations simultaneously feed one railway section. this section is called the inter substation zone and is in this case the on

11、ly zone which is being fed.in the case of a breakdown or maintenance work it is possible that one railway substation becomes switched off or unplugged. a scheme like this always has higher currents and voltage losses. therefore, it may pose certain limitations on trains' admission.for a double t

12、rack railway section and two-side feed it is common to make an additional connection of traction networks of two tracks by means of a so-called sectioning post (figure 1). the sectioning post allows to make currents in these two traction networks equal. this decreases voltage and power losses; thus,

13、 the sectioning post should normally be operational.figure 1: primary feeding scheme for a double track section.figure 2: separate feeding of two tracks.when a sectioning post goes down (or is switched off), the scheme looks more like figure 2 and is called the separate feeding scheme.we have seen t

14、wo possible feeding schemes in normal mode. by "normal mode" we mean any situation where all railway stations remain operational (as opposed to "breakdown mode", when one of them is down).2 modellingthe problem solution consists of following issues:1) create a computer model capa

15、ble of predicting power supply system working conditions.2) the model should have direct correspondence to the real railway section prototype and should simulate its features as accurate as possible.3) the model should calculate power supply system working conditions both in normal and emergency mod

16、es.4) the model should give recommendations on limitations of train positioning and movements inemergency mode. (if deemed necessary. it is possible to decrease the number of trains on an intersubstation zone or to increase the time interval between trains).2.1 choosing a modelling methodthere are s

17、everal different methods for calculating power supply system parameters. one big group of methods uses average traffic estimation. calculation in this case is based on mean and mean-square values of train currents, feeder currents, feeder wing currents and substation currents (average values are cou

18、nted for every 60 km zone).these methods are used in railway section power supply systems design only when the train schedule is totally unknown. in this case the only data one can rely on is the number of trains in a day and a railway section profile. the latter parameter determines power expenses

19、and train currents.the other group of methods is used when train schedule is available or when there is enough information about train positioning rules for the model to generate a schedule similar to a real one. here we can consider separate time moments: for every moment there is a scheme created

20、(so-called"moment scheme"). the coordinates of all the trains make part of such a moment scheme, as well as the currents they consume.the latter group of methods gives more accurate results when a condition is met that the number of moment schemes within a day is more than 1440 (number of

21、minutes in 24 hours).obviously, so much calculation could pose significant burden should it be executed by hand-of course, this is absolutely not a problem for a computer model. this was one of the main reasons for us to use a method from the second group. input data is an array of train currents co

22、llected on real trains or calculated with taking section profile (200 metres accuracy) and train's weight into account. the train schedule or the positioning rules are also defined.2.2 modelling the normal modelet us first consider modelling single track railway sections. note the main parameter

23、s that should be determined by the working model:* maximum traction network currents* maximum voltage lossesthe current in traction network should not exceed the bound permissible by heating norms. voltage losses should not be too large because train speed depends on the voltage. according to the ru

24、ssian standards, if the voltage in traction network is 27.5 kv, minimal possible voltage on a locomotive should be 21 kv (which means the losses should never exceed 6.5 kv)on design stage the type and diameter of a traction network is determined according to these three criteria: * costs* maximum tr

25、action network current* maximum voltage lossesit is common to start the research from the least possible traction network diameter. then it is increased until all three choice criteria are met.on this stage a special train positioning is used: a pack of cargo trains is formed with a minimal possible

26、 gap in between and sent to one direction. most cargo trains in this pack have average weight. but some of them (usually one or two) have maximum weight allowed for the inter substation zone.it should be noted that the number of trains in a pack, as well as the number of "heavy" trains is

27、determined by a special standard document that fixes their dependency from the overall number of trains on that particular direction. this document is always a very important part of research on russian railway power supply systems design (see table 1).number of trains in a daytime interval(minutes)

28、number of cargo trains in a packcargopassengerup to 24up to 20202more than 2015324-36up to20124more than 2010637-48up to 2095more than 208749-72up to 2087more than 20610more than 72up to 2078more than 20512table 1: determining the number of cargo trains and the time interval between subsequent train

29、s in a pack.additionally, the model takes care of:* different ordering of average cargo trains and heavy cargo trains* displacement interval (the time difference between arrival on the inter substation zone of trains from one direction and the other)* feeder length (the length of the feeding wire wh

30、ich connects railway substation with traction network)it is worth mentioning that some railway sections place substations on some distance from the railway. if the length of the feeders is long enough to influence the voltage on the locomotive, this should be taken into account.it is also possible t

31、o have one railway substation placed at a distance with a feeder length of several kilometres, while the other one is placed directly on a railway. this leads to the currents of the substation with a shorter feeder length to be always greater than the currents of the substation with a longer feeder.

32、 in order to compensate the currents it is possible to artificially increase the length of a feeder on the substation which is "too close" to the railway (figure 3).figure 3: artificial increase in feeder length.taking all section peculiarities into account is a distinct feature of our mod

33、el: it also allows to change the length and resistance of a feeder. in order to completely simulate trains moving on a real life railway section, the model utilises data about points where the trains coming from different directions can pass by each other.during simulation railway substation current

34、s and voltage losses are calculated every minute. later their maximums are determined and produced.2.3 modelling the breakdown modeif one of the railway substations goes down, it complicates the situation for power supply system significantly. the main goal is then to not let breakdown mode become e

35、mergency mode. the biggest complication is that in ac systems the inter substation zone can only be fed from one side (figure 4)-adjacent inter substation zones are fed from different phases.figure 4: switching to one-sided feeding when one railway substation is down.when one substation falls off, i

36、t can also result in a brief break in train traffic. trains in this case can be accumulated at one of the stations. in order to repair this omission when the traffic is restored, the trains are sent with minimum possible gaps. this mode is called full use of carrying capacity of arailway section.thu

37、s, on design stage heating of the traction wire should be checked in two conditions:* separate feeding of tracks on double track zones* train traffic with minimal time intervals between trainsapparently, the currents of two adjacent railway substations rise significantly when one-sided feeding schem

38、e is launched. yet it should be impossible for these currents to hit the maximum limit, otherwise the traction network wire will experience a breach in mechanical durability.increase of currents in traction network not only complicates power supply system working conditions, but also causes high ele

39、ctromagnetic impact on communication lines located close to the railway.the voltage losses increase, too. it makes sense to assume that the minimal voltage level in traction network will be experienced in proximity of the switched off substation (at the end of console feeding zone).uncontrolled drop

40、 in voltage level can lead to disconnection of locomotives. therefore it is particularly important to predict how the power supply system will operate in the breakdown mode.a breakdown mode cannot hold on for long (it usually takes up to several hours). it is possible to limit the number of trains m

41、oving inside the inter substation zone and to increase time intervals between trains.with a model which takes the section profile into account, it is possible to research breakdown modes for every single substation. the model calculates voltage levels in traction network and currents along the whole

42、 length of it. it is also possible to change train speed and time intervals between trains . during simulations, the model counts the voltage on each of the electric locomotives and chooses the minimum. the minimum value is then compared to the allowed absolute minimum-if the voltage is too low, the

43、 time interval is increased by one minute: (1)then the model starts the simulation over. this stepwise optimisation of time intervals between trains yields in the time interval which is minimal acceptable for a fixed train speed.another outcome is an array of currents on all elements of inter substa

44、tion zone (with an accuracy of 3 km). these currents can be used to calculate electromagnetic influence on adjacent communication lines.2.4 model algorithmthe model runs in an intemet browser. all data available from the railway experts about the section profile is already incorporated in it, as are

45、 the abovementioned formulae and methods. first, the user chooses the inter substation zone from a predefined list of zones on which the data is available to the application. this choice determines all train currents and positions of intermediate stations. then, it is possible to provide additional

46、input data: fix the train speed, choose the number of trains in a pack, minimum time interval between trains, traction network type, its resistance, displacement interval, etc. data is checked for validity, and the simulation process starts. visualising every step. every "minute" a moment

47、scheme is calculated: the current of each substation and the voltage on each locomotive are determined, saved and compared to the allowed bounds. when the last train leaves the inter substation zone and there are no more trains waiting to be let in. the simulation stops. all simulation outcomes such

48、 as maximum voltage loss, maximum current and the time interval between trains that meets all the conditions are displayed. this is how the model works for the simplest possible configuration. we have dealt with more complex real life situations, for example, they can combine double track and single

49、 track zones, they can have more than two different types of trains, etc.3 conclusionit has been shown why and when it is necessary to predict different functioning modes of a railway power supply system. predicting normal working mode is needed when designing a system (when electrifying new railway

50、 section). predicting breakdown mode is needed for train trafficmanagement on the fly in the case of a non-working railway substation. the principles of creating the model with taking the section profile into account were substantiated. a working computer application that allows for checking railway

51、 power supply system reliability was implemented. the results of the research were used in several big electrification projects. the program itself is still being used for educational purposes in rostov state university of transport communications.铁路环境监测,2006.工程与技术国际会议协会2006 11月29日30日 页码:6366电机工程师协会

52、 会议记录预测铁路供电系统工作模式的方法和工具zaytseva, l.a.; zaytsev, v.v.罗斯托夫州立交通通讯大学,列宁街,44/6,高级旅客列车.23,344038 罗斯托夫顿河,俄罗斯 tvadimcs.vu.nl,传真:+31(20)5987653关键词:电源,电气化,故障模式,模拟摘要这项研究是专门致力于设计和实施计算机应用来预测铁路供电系统的运行情况的(包括筹备和正式运行阶段)。详细地描述了一个火车运动地仿真模型的过程。两种工作模式是考虑所需的硬件可靠性估算:一种为正常模式(标准条件)和一种故障模式(当一个变电站不能正常运行时)。对获得的结果进行模型分析和实施可以表明其

53、可靠性。在探索模型的同时,我们能确定列车间的最小间隔时间,估计出可能的最大电流、电压损失以及其他的一些参数。1 绪论在俄罗斯,铁路电气化在过去的十年期间一直是一个热门的话题。提出了很多用于解决电气化区经济效益的方案。要求成本应尽可能低,但又不妨碍可靠性,而且要求可靠性居高不下。为了在铁路供电方面做出最好的选择,通常要检查数种变量。选择一种最为经济可靠的用来部署。计算机模型可以用来预测真实的供电系统是如何工作的。这种方式将在论文以下的章节中考虑到。模型要尽可能接近地在多种允许的模式中模拟火车地运动和供电系统的行为。通过允许的方式两个参数基本上意味着:列车间的时间间隔(间隙)、列车编组和定位。最困

54、难的问题类型是模拟列车在单线铁路区段运行。通常让一些火车成群的在单一轨道区段上朝一个方向开(火车间有固定的间隙),让后让火车往另一方向开。在这群里的火车间的时间间隔可能是最小的,这样可以加大火车牵引网络的负荷。计算机模型考虑到在一个铁路区段的单一轨道上用任何火车定位来预测供电系统的工作条件。一个供电系统的工作模式还取决于某一特定区段的输送计划。初级模式的单一区段是由两边共同供电的。用这个方案,两相邻铁路变电所同时对一个区段供电。这个区段被称为除变电站区,并在此情况下,唯一受电的地带。在发生故障或维修工作的情况下,可能是由于某铁路变电所关掉或堵塞。像这样的一个方案总是有很高的电流与电压的损失。因

55、此,它可能限制火车的出入。为了双轨道和双边供电,通常是采用所谓的切片做出一条双轨道的额外牵引线(如图1所示)。这一切片使得复线牵引网间电流平衡。这样可以减少电压和功率的损失;因此,这种切片应被普遍采用。图1:复线区段主要供电方案图2:复线分开供电当一个切片走低后(或关掉),这个方案更像图2所示的分开供电的形式。我们已经知道了在正常模式下有两种可能的供电模式。正常模式是指在任何情况下,各车站仍正常运行(当有一个不能正常运行时,就为故障模式)。2 模拟问题的解决方案包括以下问题:1) 建立一个计算机模型,就可以预知供电系统的工作条件2) 这个模型应该有直接对应的真实的铁路区段,并应模拟其特点,越准

56、确越好。3) 该模型要计算供电系统的工作状况,包括正常和紧急两种模式。4) 模型要在紧急模式中列车定位和运行的局限性上给与建议。(如认为有必要,它可以减少变电所之间的列车数或者增加列车的时间间隔。2.1 选择建模的方法计算供电系统参数的方法有很多种。一个重要的方法是,利用平均流量来估算。在此情况下,计算是基于列车电流、馈线电流、馈线电流、变电站电流(平均值以每计算)。自由当列车明细表不明的时候,这些方法才被用于设计铁路区段供电系统的设计。在这种情况下,唯一的一个可靠数据是一天中和铁路区段的列车数,后者的参数可以确定电力支出和火车电流。当可以用到火车的明细表或者有足够的火车定位的信息,这种信息可

57、以通过模型产生相似的时间表来获得,那么就可以用另外的一种方法。在这里,我们可以考虑单独的时间矩:任何时刻都有图表产生(所谓的矩图表)。这个矩图表是有所有列车的坐标组成的,以及他们消耗的电流。当条件得到满足时,后一组方法给出更精确的结果。这种条件是指每天超过1440的时刻计划有多少(分钟数在20小时以内)。当然如果用手工来完成的话,显然如此计算可能构成重大的负担,但这对计算机模型来所的话,这绝对不是一个问题。这是我们用第二组方法的一个主要原因。输入的数据是一组收集的真实火车的电流或者计算,该计算采取剖面(200米精度)和列车的负载。当然,列车时刻表和定位规则也被界定了。2.2 模拟正常模式让我们

58、先考虑模拟单轨迹铁路路段。注意到主要参数应该由工作模式来确定:最大牵引网电流最大电压损失牵引网电流不应超过一定的允许范围。电压损失不能太大,以为火车的速度取决于电压。根据俄罗斯标准,如果牵引网电压是27.5kv,对火车的最小可能电压是21kv(即亏损电压不能超过650kv)关于设计阶段的类型和牵引网直径是根据以下三个标准来确定的:耗费最大牵引网电流最大电压损失从牵引网直径开始研究的可能性很小。直到符合这三个选择的条件,可能性就增加了。现阶段专列定位被采用:货物列车间形成可能存在的很小间隙和往一个放心开。多数货物列车由一个平均的负载。但有些(通常是一列或两列)有变电所间地带允许的最大负荷。应该可以记录下货物列车的数量以及“沉重”列车的数量。沉重列车的数量可以由特别的规范性文件确定的,文件记录着特定方向的所有列车数。这分文件是研

温馨提示

  • 1. 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
  • 2. 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
  • 3. 本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
  • 4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
  • 5. 人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
  • 6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
  • 7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。

评论

0/150

提交评论