1、PDF外文：http:/ 1 Railway Condition Monitoring,2006. The Institution of Engineering and Technology International Conference on 29-30 Nov.2006 Page(s):63-66 IEE CNF METHODS AND TOOLS FOR PREDICTING WORKING MODES OF RAILROAD POWER-SUPPLY SYSTEMS Zaytseva, L.A.； Zaytsev, V.V. Rostov State Universit
2、y of Transport Communications, Lenin Street, 44/6, Apt. 23, 344038 Rostov-on-Don, Russia tvadimcs.vu.nl, fax: +31(20)5987653 Keywords: power supply, electrification, breakdown mode, modelling. Abstract This research is dedicated to design and implementation of a computer application for predic
3、ting the functioning of a railway power 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 c
4、onditions) and a breakdown mode (when 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
5、 well as other parameters. 1 Introduction During 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 2 low as possible withou
6、t hindering reliability, requirements for which always 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 supp
7、ly system will work. Such a model is considered in the 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 (o
8、r gap)between trains and train grouping and positioning. 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), a
9、nd only then let the trains go in the other direction. The time interval between trains inside such a pack can be minimal, which leads to load increase for the traction network. A computer model allows for predicting power supply system working conditions with any train positioning on a single track
10、 railway section. The working modes of a power supply system 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 c
11、alled the inter substation zone and is in this case the only zone which is being fed. In the case of a breakdown or maintenance work it is possible that one 3 railway substation becomes switched off or unplugged. A scheme like this always has higher currents and voltage losses. Therefore, it m
12、ay pose certain limitations on trains' admission. For a double track 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 tra
13、ction networks equal. This decreases voltage and power losses； thus, 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 schem
14、e looks more like Figure 2 and is called the separate feeding scheme. We have seen two 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 Modelling The problem solution consists of following issues:
