【正文】 1 Railway Condition Monitoring,2020. The Institution of Engineering and Technology International Conference on 2930 Page(s):6366 IEE CNF METHODS AND TOOLS FOR PREDICTING WORKING MODES OF RAILROAD POWERSUPPLY SYSTEMS Zaytseva, .。 Zaytsev, . Rostov State University of Transport Communications, Lenin Street, 44/6, Apt. 23, 344038 RostovonDon, Russia , fax: +31(20)5987653 Keywords: power supply, electrification, breakdown mode, modelling. Abstract This research is dedicated to design and implementation of a puter application for predicting 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 conditions) 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 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 without 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 supply 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 (or 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 mon 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. The time interval between trains inside such a pack can be minimal, which leads to load increase for the traction work. A puter 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 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 called 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 bees switched off or unplugged. A scheme like this always has higher currents and voltage losses. Therefore, it may pose certain limitations on trains39。 admission. For a double track railway section and twoside feed it is mon to make an additional connection of traction works of two tracks by means of a socalled sectioning post (Figure 1). The sectioning post allows to make currents in these two traction works 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 scheme 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