A Simulation Tool for the Design of the Electrical Supply System of High-Speed Railway Lines E. Pilo, L. Rouco, A. Fernández Universidad Pontificia Comillas C. Alberto Aguilera, 23 28015 Madrid, Spain A. Hernández-Velilla SEMI C. Barquillo, 19 28004 Madrid, Spain Abstract-The design of the electrical supply system of high-speed railway lines involves the selection of the single phase system (one or two active conductors: 1x25kV or 2x25 kV), the design of the catenary, and the location and sizing of the substations and the autotransformers in case of a 2x25 kV system. The electrical system should be designed so the train voltages are in the admissible range and the conductor currents and transformer powers are smaller that their rated values. This paper presents a simulation tool for the design of the electrical supply system of high-speed railway lines. The tool is composed of two main modules: (1) the simulator of the railway line and (2) the electrical system simulator. The railway line simulator determines the position and power consumption of each train at each time step provided the line operation policy. The electrical system simulator solves the AC network at each time step and provides the catenary and train voltages, the conductor currents and the transformer power flows. Keywords- high-speed railways, electrical supply system, traffic simulator, electrical simulator. I. INTRODUCTION The development of high-speed railway lines starts in France at the beginning of the 80’s when the line Paris – Lyon was opened [1] (the first section Lyon – St. Florentin was opened in 1981 and the full line Paris - Lyon was opened in 1983). The French developments have been followed by other ones in Germany, Italy and Belgium. The first Spanish railway line (Madrid – Seville) was opened in 1992. It is approximately 450 km long, the nonstop trip takes 2:30 hours and the trains travel at a maximum speed of 300 km/h. The technical and economic success of that line has encouraged the Spanish government to start new projects: Madrid – Barcelona – French border (800 km), Madrid – Valencia (350 km) and Madrid – Valladolid (200 km). These projects are also supported by the European Union under the framework of the Common Transportation Policies. The line Madrid - Barcelona – French border is currently under construction. The different sections will be progressively opened in the next years: Madrid – Lleida (450 km) in 2002, Lleida – Barcelona (200 km) in 2004 and Barcelona – French Border (150 km) in 2006. This line has been designed to allow a commercial speed of 350 km/h (which means top speeds up to 385 km/h) so the trip Madrid – Barcelona will take 2:30 hours. The main components of a high-speed railway line are (i) the civil work, (ii) the electrical supply system, (iii) the control system and (iv) the rolling stock. This paper presents a simulation tool of the electrical supply system of railway lines oriented to its design. The paper is organized as follows. Section II describes the typical configurations of the electrical supply system of high- speed railway lines. Section III formulates the design problem: design variables and constraints to be considered. Section IV overviews the simulation tool. Section V and VI describe respectively the two main components of the tool: the traffic simulator and the electrical simulator. Section VII illustrates the capabilities of the tool. Section VIII offers the conclusion of the work. II. ELECTRICAL SUPPLY SYSTEM OF HIGH-SPEED RAILWAYS The electrical supply system of a high-speed railway line provides electric power of the desired characteristics (AC, single phase, 25 kV) to the trains from the high-voltage network. The main components of the system are the catenary and the substations that feed the catenary from the high-voltage network. Fig. 1 displays a typical configuration of the system. Each transformer is connected to two phases of the three-phase system. Each section of the line is independently fed by a traction substation. In case that a substation is out of service, the adjacent substations respectively feed the two parts of the corresponding section.           Fig. 1. Electrical supply system of a high-speed railway line. The catenary can be equipped with either one or two active conductors resulting respectively in the so called 1x25 kV or 2x25 kV systems (in case that the catenary voltage is 25 kV). Fig. 2 and Fig. 3 show respectively the basic topology of 1x25kV and 2x25 kV systems. Regarding the 1x25 kV