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  • 1.
    Delsing, Jerker
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Ekman, Jonas
    Mäkitalo, P.
    Niska, Stefan
    Wisten, Åke
    Sources and propagation of eectromagnetic transients in railway systems, S01-3915/08. Final Report2005Report (Other academic)
    Abstract [en]

    The railway system is continuously being updated. Upgrading axle loads, introducing new engines with increasing power needs and advanced motor control give unwanted electromagnetic consequences for electronic-, telecommunication-, and signalling systems along the track. This can, for example, lead to failure in detector systems and traffic control systems and increased cost due to corrective maintenance. This research project was initiated with the purpose of understanding origin and propagation of radiated and conducted electromagnetic transients in the railway system. To investigate the problem of radiated and conducted electromagnetic interference, it has been necessary to develop new measuring methods. Measurements have been conducted to determine if the more sensitive low voltage systems are influenced by higher voltage systems. An existing electromagnetic modeling tool has been utilized, to model crosstalk between the rails and the overhead line catenary system, and modified to incorporate a combination of two- and three- dimensional models to reduce time and space complexity. The resulting simulation environment can be used to analyze possible sources of electromagnetic disturbances in the coexisting signaling circuitry of today, and to reduce the influence of these sources. This gives a new application of the measurement method and further development of a simulation tool. One of the objectives in this project has been to find out the tolerance of the low voltage detector systems in presence of the higher voltage system used in the railways. One of the conclusions is that correct installation is important and that failure to comply with installation procedures results in high electromagnetic interference. There is no correlation between the presence of trains and randomly occurring disturbances.

  • 2.
    Ekman, Jonas
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Niska, Stefan
    PEEC based formulation suitable for electromagnetic analysis of railway structures2004In: EMC Europe 2004: International Symposium on Electromagnetic Compatibility; September 6 - 10, 2004, Technische Universiteit, Eindhoven, the Netherlands / [ed] A. P. J. van Deursen, Eindhoven: Technische Universiteit Eindhoven, 2004Conference paper (Refereed)
  • 3.
    Niska, Stefan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Electromagnetic interference: a major source of faults in Swedish railway2009In: International Journal of Pedagogy, Innovation and New Technologies, ISSN 0973-1318, E-ISSN 2392-0092, Vol. 5, no 2, p. 187-196Article in journal (Refereed)
    Abstract [en]

    Industry and the railway sector are at present entering a new era. Increasingly, the systems in operation today use electronic components instead of relay technique and the railway sector now has the opportunity to improve current systems. However when new technology is installed into old infrastructure, new knowledge has to be taken into consideration. The new technology which is to be integrated into old systems or which is to be applied when building systems from scratch should meet the requirements for electromagnetic compatibility to fit into the infrastructure. To see whether there are any problems in this area, an investigation has been performed based on the failure reporting system used by Banverket (Swedish Rail Administration). Visual inspection has been carried out in the signal and detector boxes located close to the track. Measurements on site have been conducted to follow up the investigation into the failure reporting system and the visual inspections.

  • 4.
    Niska, Stefan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    EMC in railway systems: measurements, modeling and analysis2004Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The subject of this study and resulting thesis was to investigate the electromagnetic compatibility (EMC) problems in the multi-electrical signaling circuitry along a railway track. These signaling systems have been expanding over time from buried multi-wired electrical copper cables to optical fiber cables, sometimes located parallel to the contact line in the catenaries. Systems have evolved from simple electromechanical to complex electronic systems and each one of these systems still exists and have to operate together. There intractability has to be faultless, which is unfortunately not always the case. The multi-electrical systems of the railway include the signaling systems along the railway line and security systems, for example point activation mechanism and train indication system. In addition there are detectors measuring the presence of trains, temperature sensors for the points to allow heating during winter, and sensors measuring hot bearings, hot wheels and flat wheels on passing trains. The recent increase in axle pressure from 25 to 30 tons means that higher currents in the rails are now being generated. On top of this, a new generation of trains is being introduced with regenerative electric braking system in the motor, which delivers current back into the system when slowing down the train. This makes it important to have resistant systems close to the railway environment. The systems has to have a robust construction and last over a long period of time with consideration to externally applied fields and influences of weather conditions. The location of the different systems can also be far from support, maintenance, and service. To investigate the problem of radiated and conducted electromagnetic (EM) interference, it was necessary to develop measuring methods. Measurements have been done to find out if the more sensitive systems are influenced by higher voltage systems in the signaling circuitry. An existing EM modeling tool was utilized, to model crosstalk between rails and contact lines, and modified to incorporate a combination of two- and three- dimensional models for reduced time and space complexity. The resulting simulation environment can be used to analyze possible sources of EM disturbances in the multi-electrical signaling circuitry as it is today, and to reduce the sources that generate problems. This gives a new application of the measurement method and further development of a simulation tool. One of the objectives in this project is to find out the tolerance of the low voltage detector systems in the presence of higher voltage system used in the railways. One of the conclusions is that correct installation is important and failure to comply with installation procedures results in high EM interference.

  • 5.
    Niska, Stefan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Measurements and analysis of electromagnetic interferences in the Swedish railway systems2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Presently, the existing failure reporting system at Banverket (the Swedish Rail Administration), which handles reports on the failures of the railway infrastructures and possible causes of failure, is not optimum (or most suitable) when it comes to analysis of electromagnetic compatibility (EMC)- related failures and causes. This failure reporting system is reliant on correct reporting into the system, so that the right information can be sent back to the users, the maintenance and service personnel, in real time. In general railway infrastructure operates in a complex and non-homogeneous environment where low power electronics has to function in the same environment as large voltages and currents from trains. The environment close to the railway tracks is heavily polluted by electromagnetic (EM) noise from the railway systems themselves. The reliability of railway signalling, communication, and control systems depends on the degree of galvanic isolation from EM noise. When new technologies are implemented into old installations, the complexity of the system increases, leading to new challenges which necessitate new forms of skill and competence to deal with these issues and challenges. The new technologies which are to be integrated into the old systems, or which are to be applied to build new systems, must meet the requirements for EMC in order to obtain a high degree of system reliability and ensure the problem-free operation of such systems. The complexity of the infrastructure is not easy to simulate or calculate, and consequently it is important to observe the real systems and their characteristics in real situations. Therefore, measurements were performed on real systems in operation. To perform an audit of the problems in the railway systems leading to EM noises and failures, investigations were made by studying the real systems in operation and using the existing failure (and inspection) reporting system of Banverket. A large number of measurements were made on site at detectors and signalling systems and installations. By studying and analyzing the measured data and failure reports from the databases, an effort was made to understand the causes of faults related to EMI (Electromagnetic interferences). Thereafter, visual inspection was carried out in the engineering constructions, i.e. signal and detector boxes, to verify if the recurring faults are caused by poorly designed installations and their physical environment. The visual inspections were concentrated on EMC and to the areas from where the power and communication cables entered the locations selected for study, by examining the areas where the sensitive equipment was placed. Through the visual inspection it was found that there could be improvements in two problem areas, namely installations and instructions from the suppliers of equipment, which often result in wrong installations. During this study, measurements were performed at sites which had extensive EMC and EMI problems. The measurements clearly show the erratic characteristics of the equipment and systems used in signalling and detector installations, mainly leading to EMC and EMI problems. For example, the measurements from detectors show that random transients appear even when a train is not present, and the measurements in the signal box show a completely different behaviour where the measuring equipment showed a reading of over -100 volts in a 27 V system. These measurements and the results from the subsequent analyses show EMI characteristics which are totally unexpected. The detailed analysis of the failure reporting systems and databases shows that most of the failure causes are related to EMC problems. The fault reporting system is not configured to identify the failure causes as EMC or EMI problems. Therefore, this has to be investigated to identify the cause so that corrective actions can be initiated to restore the system to an operating condition. The research study has helped in understanding the function of railway signalling and detector installations from an EMC and EMI point of view. The knowledge generated will be of assistance in designing new signalling and detector equipment which will have a higher level of reliability, leading to a smaller number of failures and EMC problems. The study has made a contribution towards an understanding of the EMC and EMI characteristics of the signalling and detector infrastructure of the railway system. These characteristics often lead to failures resulting in train delays.

  • 6. Niska, Stefan
    et al.
    Ekman, Jonas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Analysis and modeling of EMC problems in railway detector systems2004In: EMC Europe 2004 :: International Symposium on Electromagnetic Compatibility; September 6 - 10, 2004, Technische Universiteit, Eindhoven, the Netherlands / [ed] A. P. J. van Deursen, Eindhoven: Technische Universiteit Eindhoven, 2004Conference paper (Refereed)
  • 7. Niska, Stefan
    et al.
    Ekman, Jonas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Combining 2D transmission line models with 3D PEEC models2004In: Proc. of EMB04, Gothenburg, Sweden, Oct., 2004., 2004Conference paper (Refereed)
  • 8. Niska, Stefan
    et al.
    Ekman, Jonas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Electromagnetic compatibility problems in railway detector systems2004In: Proceedings of the 12th Nordic Seminar on Railway Technology, 2004Conference paper (Refereed)
  • 9.
    Niska, Stefan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Ekman, Jonas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    EMC problems in railway detector systems2004Conference paper (Refereed)
  • 10. Niska, Stefan
    et al.
    Schunnesson, Håkan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Measurements and analysis of electromagnetic interference in a railway signal box: a case study2011In: International Journal of Reliability, Quality and Safety Engineering (IJRQSE), ISSN 0218-5393, Vol. 18, no 3, p. 285-303Article in journal (Refereed)
    Abstract [en]

    In general railway infrastructure operates in a complex and non homogeneous environment where low power electronics has to function in the similar environment as large voltages and currents from the trains. The environment close to the railway tracks is heavily polluted by electromagnetic (EM) noise from the railway systems itself. The reliability of the railway signalling-, communication-, and control system depends on the degree of isolation from EM noise. It is important to observe the real system and its characteristics in real situation. The complexity of the infrastructure is not easy to simulate or calculate, and therefore measurements were performed on real system in operation. A large number of measurements were made on site at signalling systems and installations of Banverket (the Swedish Rail Administration). By studying and analyzing these measurements, the extent of EMI (Electromagnetic interferences) -related faults can be estimated. In situ measurements must be performed on systems that have obvious problems show increasingly fast and high transients in a DC signalling subsystem. The statistics also show an increased activity of transients during a period before a certain circuit in this system gets out of order. The presented results clearly show how the electromagnets interference effects he signalling system in a signalling box. The measurements in this case study have provided new information on a railway subsystem and have revealed frequencies that are difficult to explain at this moment.

  • 11. Niska, Stefan
    et al.
    Schunnesson, Håkan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Nyström, Birre
    Causes of EMC disturbance on the railway: a study of recurring faults in the signal box at Oxmyran station in Sweden2009In: International Journal of COMADEM, ISSN 1363-7681, Vol. 12, no 2, p. 20-29Article in journal (Refereed)
    Abstract [en]

    Failure reporting systems in the railway industry are reliant on correct reporting into the system, so that the right information may be send back to the user. This information is needed for correct decision-making in the maintenance process. For failure due to electromagnetic disturbance a correct classification can be very difficult to make in the field, with limited time available for the analysis of failure causes. The Swedish Railway Administration (Banverket) has a problem in a signal box at Oxmyran Station, where faults are reported frequently. The wide variation in the reported causes of the disturbance of the electromagnetic compatibility makes it very difficult to pinpoint the real causes of the events that lead to failure. In this paper, a large number of causes are investigated, discussed and dismissed as reasons for the large number of faults at Oxmyran. Measurements on site, however, show that the electromagnetic interference is much higher at Oxmyran than at the reference station at Ore Alv. The main purpose of this study was to investigate the probable source and the subsequent sequence of events that result in faults that break the RC circuit at Oxmyran.

  • 12.
    Wisten, Åke
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Niska, Stefan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Ekman, Jonas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Björklöf, Dag
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Delsing, Jerker
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Experimental investigation of the EM noise environment surrounding detector systems at Swedish railways2006In: IEE Proceedings - Electric Power Applications, ISSN 1350-2352, E-ISSN 1359-7043, Vol. 153, no 2, p. 191-196Article in journal (Refereed)
    Abstract [en]

    The close environment of railway tracks is heavily polluted by electromagnetic noise from the railway system itself. The reliability of railway signalling, communication, and control systems depends on good immunity to electromagnetic noise. There are sometimes false detector signals indicating non-existing flat wheels and ghost trains. A possible reason for detector failures is interference by transient voltage peaks in the detector system. Thus characterisation has been made of the electromagnetic environment around the detector system located at the track. The investigation shows that the typical electromagnetic environment is a combination of broadband low-level noise, and rare fast transients of potentially harmful amplitudes.

1 - 12 of 12
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