外文翻譯預(yù)測(cè)鐵路供電系統(tǒng)工作模式的方法和工具

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.鐵路環(huán)境監(jiān)測(cè)，2006.工程與技術(shù)國(guó)際會(huì)議協(xié)會(huì)2006 11月29日30日 頁(yè)碼：6366電機(jī)工程師協(xié)會(huì)

52、 會(huì)議記錄預(yù)測(cè)鐵路供電系統(tǒng)工作模式的方法和工具zaytseva, l.a.; zaytsev, v.v.羅斯托夫州立交通通訊大學(xué)，列寧街，44/6，高級(jí)旅客列車(chē).23，344038 羅斯托夫頓河，俄羅斯 tvadimcs.vu.nl,傳真：+31(20)5987653關(guān)鍵詞：電源，電氣化，故障模式，模擬摘要這項(xiàng)研究是專門(mén)致力于設(shè)計(jì)和實(shí)施計(jì)算機(jī)應(yīng)用來(lái)預(yù)測(cè)鐵路供電系統(tǒng)的運(yùn)行情況的（包括籌備和正式運(yùn)行階段）。詳細(xì)地描述了一個(gè)火車(chē)運(yùn)動(dòng)地仿真模型的過(guò)程。兩種工作模式是考慮所需的硬件可靠性估算：一種為正常模式（標(biāo)準(zhǔn)條件）和一種故障模式（當(dāng)一個(gè)變電站不能正常運(yùn)行時(shí)）。對(duì)獲得的結(jié)果進(jìn)行模型分析和實(shí)施可以表明其

53、可靠性。在探索模型的同時(shí)，我們能確定列車(chē)間的最小間隔時(shí)間，估計(jì)出可能的最大電流、電壓損失以及其他的一些參數(shù)。1 緒論在俄羅斯，鐵路電氣化在過(guò)去的十年期間一直是一個(gè)熱門(mén)的話題。提出了很多用于解決電氣化區(qū)經(jīng)濟(jì)效益的方案。要求成本應(yīng)盡可能低，但又不妨礙可靠性，而且要求可靠性居高不下。為了在鐵路供電方面做出最好的選擇，通常要檢查數(shù)種變量。選擇一種最為經(jīng)濟(jì)可靠的用來(lái)部署。計(jì)算機(jī)模型可以用來(lái)預(yù)測(cè)真實(shí)的供電系統(tǒng)是如何工作的。這種方式將在論文以下的章節(jié)中考慮到。模型要盡可能接近地在多種允許的模式中模擬火車(chē)地運(yùn)動(dòng)和供電系統(tǒng)的行為。通過(guò)允許的方式兩個(gè)參數(shù)基本上意味著：列車(chē)間的時(shí)間間隔（間隙）、列車(chē)編組和定位。最困

54、難的問(wèn)題類型是模擬列車(chē)在單線鐵路區(qū)段運(yùn)行。通常讓一些火車(chē)成群的在單一軌道區(qū)段上朝一個(gè)方向開(kāi)（火車(chē)間有固定的間隙），讓后讓火車(chē)往另一方向開(kāi)。在這群里的火車(chē)間的時(shí)間間隔可能是最小的，這樣可以加大火車(chē)牽引網(wǎng)絡(luò)的負(fù)荷。計(jì)算機(jī)模型考慮到在一個(gè)鐵路區(qū)段的單一軌道上用任何火車(chē)定位來(lái)預(yù)測(cè)供電系統(tǒng)的工作條件。一個(gè)供電系統(tǒng)的工作模式還取決于某一特定區(qū)段的輸送計(jì)劃。初級(jí)模式的單一區(qū)段是由兩邊共同供電的。用這個(gè)方案，兩相鄰鐵路變電所同時(shí)對(duì)一個(gè)區(qū)段供電。這個(gè)區(qū)段被稱為除變電站區(qū)，并在此情況下，唯一受電的地帶。在發(fā)生故障或維修工作的情況下，可能是由于某鐵路變電所關(guān)掉或堵塞。像這樣的一個(gè)方案總是有很高的電流與電壓的損失。因

55、此，它可能限制火車(chē)的出入。為了雙軌道和雙邊供電，通常是采用所謂的切片做出一條雙軌道的額外牽引線（如圖1所示）。這一切片使得復(fù)線牽引網(wǎng)間電流平衡。這樣可以減少電壓和功率的損失；因此，這種切片應(yīng)被普遍采用。圖1：復(fù)線區(qū)段主要供電方案圖2：復(fù)線分開(kāi)供電當(dāng)一個(gè)切片走低后（或關(guān)掉），這個(gè)方案更像圖2所示的分開(kāi)供電的形式。我們已經(jīng)知道了在正常模式下有兩種可能的供電模式。正常模式是指在任何情況下，各車(chē)站仍正常運(yùn)行（當(dāng)有一個(gè)不能正常運(yùn)行時(shí)，就為故障模式）。2 模擬問(wèn)題的解決方案包括以下問(wèn)題：1） 建立一個(gè)計(jì)算機(jī)模型，就可以預(yù)知供電系統(tǒng)的工作條件2） 這個(gè)模型應(yīng)該有直接對(duì)應(yīng)的真實(shí)的鐵路區(qū)段，并應(yīng)模擬其特點(diǎn)，越準(zhǔn)

56、確越好。3） 該模型要計(jì)算供電系統(tǒng)的工作狀況，包括正常和緊急兩種模式。4） 模型要在緊急模式中列車(chē)定位和運(yùn)行的局限性上給與建議。（如認(rèn)為有必要，它可以減少變電所之間的列車(chē)數(shù)或者增加列車(chē)的時(shí)間間隔。2.1 選擇建模的方法計(jì)算供電系統(tǒng)參數(shù)的方法有很多種。一個(gè)重要的方法是，利用平均流量來(lái)估算。在此情況下，計(jì)算是基于列車(chē)電流、饋線電流、饋線電流、變電站電流（平均值以每計(jì)算）。自由當(dāng)列車(chē)明細(xì)表不明的時(shí)候，這些方法才被用于設(shè)計(jì)鐵路區(qū)段供電系統(tǒng)的設(shè)計(jì)。在這種情況下，唯一的一個(gè)可靠數(shù)據(jù)是一天中和鐵路區(qū)段的列車(chē)數(shù)，后者的參數(shù)可以確定電力支出和火車(chē)電流。當(dāng)可以用到火車(chē)的明細(xì)表或者有足夠的火車(chē)定位的信息，這種信息可

57、以通過(guò)模型產(chǎn)生相似的時(shí)間表來(lái)獲得，那么就可以用另外的一種方法。在這里，我們可以考慮單獨(dú)的時(shí)間矩：任何時(shí)刻都有圖表產(chǎn)生（所謂的矩圖表）。這個(gè)矩圖表是有所有列車(chē)的坐標(biāo)組成的，以及他們消耗的電流。當(dāng)條件得到滿足時(shí)，后一組方法給出更精確的結(jié)果。這種條件是指每天超過(guò)1440的時(shí)刻計(jì)劃有多少（分鐘數(shù)在20小時(shí)以內(nèi)）。當(dāng)然如果用手工來(lái)完成的話，顯然如此計(jì)算可能構(gòu)成重大的負(fù)擔(dān)，但這對(duì)計(jì)算機(jī)模型來(lái)所的話，這絕對(duì)不是一個(gè)問(wèn)題。這是我們用第二組方法的一個(gè)主要原因。輸入的數(shù)據(jù)是一組收集的真實(shí)火車(chē)的電流或者計(jì)算，該計(jì)算采取剖面（200米精度）和列車(chē)的負(fù)載。當(dāng)然，列車(chē)時(shí)刻表和定位規(guī)則也被界定了。2.2 模擬正常模式讓我們

58、先考慮模擬單軌跡鐵路路段。注意到主要參數(shù)應(yīng)該由工作模式來(lái)確定：最大牽引網(wǎng)電流最大電壓損失牽引網(wǎng)電流不應(yīng)超過(guò)一定的允許范圍。電壓損失不能太大，以為火車(chē)的速度取決于電壓。根據(jù)俄羅斯標(biāo)準(zhǔn)，如果牽引網(wǎng)電壓是27.5kv，對(duì)火車(chē)的最小可能電壓是21kv（即虧損電壓不能超過(guò)650kv）關(guān)于設(shè)計(jì)階段的類型和牽引網(wǎng)直徑是根據(jù)以下三個(gè)標(biāo)準(zhǔn)來(lái)確定的：耗費(fèi)最大牽引網(wǎng)電流最大電壓損失從牽引網(wǎng)直徑開(kāi)始研究的可能性很小。直到符合這三個(gè)選擇的條件，可能性就增加了?，F(xiàn)階段專列定位被采用：貨物列車(chē)間形成可能存在的很小間隙和往一個(gè)放心開(kāi)。多數(shù)貨物列車(chē)由一個(gè)平均的負(fù)載。但有些（通常是一列或兩列）有變電所間地帶允許的最大負(fù)荷。應(yīng)該可以記錄下貨物列車(chē)的數(shù)量以及“沉重”列車(chē)的數(shù)量。沉重列車(chē)的數(shù)量可以由特別的規(guī)范性文件確定的，文件記錄著特定方向的所有列車(chē)數(shù)。這分文件是研