Limiting the influence of regulated electrical drainage on track circuits

For the past two years, the authors of this paper have been working on the development of a new regulated electrical drainage system for tram tracks, which may also be used on railways in the future. When this drainage is used on train tracks equipped with track circuits, it is necessary to make sure that the drainage does not generate current harmonics which may be dangerous for the correct functioning of the circuits. In the Czech Republic, requirements regarding the operation of track circuits are stated by Standard CSN 342613. When the drainage was tested on tram tracks, where there are no track circuits, it was found out that in certain operation modes, the drainage generates frequencies which collide with the frequencies of track circuits. Therefore, a passive filter was designed to solve this problem. With the use of computer simulation and measurements on a laboratory model, it was verified that this filter is able to suppress unwanted current harmonics, so that they are in agreement with the above mentioned Standard. These measurements and simulations are described in this paper.Web of Science245565

Research and innovation in power electronics systems applied to energy management

The Power Electronics Systems Group (GSEP) at University Carlos III de Madrid (Spain) offers its wide experience and background in consultancy, R&D projects with private and public funding and pre-industrial prototype building in four main topics: energy conversion (design, modelling and prototyping of equipments and systems), magnetic components modelling and design, photovoltaic systems and electromagnetic compatibility (EMC)

Railway interference management: TLM modelling in railway applications

This thesis deals with the application of analytical and numerical tools to Electromagnetic Compatibility (EMC) management in railways. Analytical and numerical tools are applied to study the electromagnetic coupling from an alternating current (AC) electrified railway line, and to study the electrical properties of concrete structure - a widely used component within the railway infrastructure. An electrified railway system is a complex distributed system consisting of several sub-systems, with different voltage and current levels, co-located in a small area. An analytical method, based on transmissions line theory, is developed to investigate railway electromagnetic coupling. The method is used to study an electrified railway line in which the running rails and earth comprise the current retum path. The model is then modified to include the presence of booster transformers. The analytical model can be used to study the railway current distribution, earth potential and electromagnetic coupling - inductive and conductive coupling - to nearby metallic structures. The limiting factor of the analytical model is the increasing difficulty in resolving the analytical equation as the complexity of the railway model increases. A large scale railway numerical model is implemented in Transmission Line Matrix (TLM) and the electromagnetic fields propagated from the railway model is studied. As this work focuses on the direct application of TLM in railway EMC management, a commercially available TIM software package is used. The limitation of the numerical model relates to the increased computation resource and simulation time required as the complexity of the railway model increases. The second part of this thesis deals with the investigation of the electrical properties of concrete and the development of a dispersive material model that can be implemented in numerical simulators such as TIM. Concrete is widely used in the railway as structural components in the construction of signalling equipment room, operation control centres etc. It is equally used as sleepers in the railway to hold the rails in place or as concrete slabs on which the whole rail lines are installed. It is thus important to understand the contribution of concrete structures to the propagation of electromagnetic wave and its impact in railway applications. An analytical model, based on transmission line theory, is developed for the evaluation of shielding effectiveness of a concrete slab; the analytical model is extended to deal with reinforced concrete slab and conductive concrete. The usefulness and limitation of the model is discussed. A numerical model for concrete is developed for the evaluation of the effectiveness of concrete as a shield. Initially, concrete is modelled as a simple dielectric material, using the available dielectric material functionality within TLM. It is noted that the simple dielectric model is not adequate to characterise the behaviour of concrete over the frequency range of interest. Better agreement is obtained with concrete modelled as a dispersive material having material properties similar to that exhibited by materials obeying Debye equation. The limitations of the dispersive material model are equally discussed. The design of conductive concrete is discussed, these have application in the railway industry where old existing structures are to be converted to functional rooms to house sensitive electronic system. A layer of conductive concrete can be applied to the facade to enhance the global shielding of the structure

Formation of an integrated financial regulation system of transport corporations’ economic development

Scientific findings of this article correspond with the fact that the development of interacting business entities is quite diverse. This affects the efficiency of corporations’ budget management. So, a need arises to adjust the financial assets applied to the development of integrated enterprises, basing on their economic compatibility evaluation. Authors suggest using the companies’ development intensity determined by the increasing qualitative business activity indicators compared to the increasing quantitative ones. Theoretical economics gives no clear definition of compatibility of developing companies. Economic practices do not pay proper attention to the development of effective financial regulation of economic development of companies integrated into a corporation. The article suggests original definitions of economic compatibility as well as the model of forming the integrated system of transport companies’ economic development on the basis of morphological approach. Theoretical and methodological findings are approved in the business activity of transport corporationspeer-reviewe

Power quality and electromagnetic compatibility: special report, session 2

The scope of Session 2 (S2) has been defined as follows by the Session Advisory Group and the Technical Committee: Power Quality (PQ), with the more general concept of electromagnetic compatibility (EMC) and with some related safety problems in electricity distribution systems. Special focus is put on voltage continuity (supply reliability, problem of outages) and voltage quality (voltage level, flicker, unbalance, harmonics). This session will also look at electromagnetic compatibility (mains frequency to 150 kHz), electromagnetic interferences and electric and magnetic fields issues. Also addressed in this session are electrical safety and immunity concerns (lightning issues, step, touch and transferred voltages). The aim of this special report is to present a synthesis of the present concerns in PQ&EMC, based on all selected papers of session 2 and related papers from other sessions, (152 papers in total). The report is divided in the following 4 blocks: Block 1: Electric and Magnetic Fields, EMC, Earthing systems Block 2: Harmonics Block 3: Voltage Variation Block 4: Power Quality Monitoring Two Round Tables will be organised: - Power quality and EMC in the Future Grid (CIGRE/CIRED WG C4.24, RT 13) - Reliability Benchmarking - why we should do it? What should be done in future? (RT 15

Sizing and Energy Management of a Hybrid Locomotive Based on Flywheel and Accumulators

The French National Railways Company (SNCF) is interested in the design of a hybrid locomotive based on various storage devices (accumulator, flywheel, and ultracapacitor) and fed by a diesel generator. This paper particularly deals with the integration of a flywheel device as a storage element with a reduced-power diesel generator and accumulators on the hybrid locomotive. First, a power flow model of energy-storage elements (flywheel and accumulator) is developed to achieve the design of the whole traction system. Then, two energy-management strategies based on a frequency approach are proposed. The first strategy led us to a bad exploitation of the flywheel, whereas the second strategy provides an optimal sizing of the storage device. Finally, a comparative study of the proposed structure with a flywheel and the existing structure of the locomotive (diesel generator, accumulators, and ultracapacitors) is presented

Evaluation of the Impact of Transient Disturbances on Railway Signaling Systems Using an Adapted Time-Frequency Analysis Method

As many other industrial environments, the railway electromagnetic environment is characterized by a large number of electromagnetic signals and disturbances. Among these, transient signals, with high energy level and wide frequency spectrum, represent an important threat to different signaling subsystems. In this paper, a new methodology dedicated to the detection and the characterization of the transient disturbances is presented. Based on a flexible and adjustable time-frequency analysis, this methodology is used to evaluate the impact of transient disturbances on a ground‑to‑train radio communication. A test bench was developed in order to validate the results of this evaluation