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  • 1. Anatory, J.
    et al.
    Theethayi, Nelson
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electricity. Avdelningen för elektricitetslära och åskforskning.
    Thottappillil, Rajeev
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electricity. Avdelningen för elektricitetslära och åskforskning.
    Kissaka, M.M.
    Mvungi, N.H.
    The Effects Of Iterconnections And Branched Network In The Broadband Powerline Communications2005In: XXVIIIth General Assembly of International Union of Radio Sciences, New Delhi, India, October 23-29, 2005Conference paper (Refereed)
  • 2.
    Anatory, Justinian
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Division for Electricity and Lightning Research.
    Theethayi, Nelson
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Division for Electricity and Lightning Research.
    Kissaka, Mussa
    Faculty of Electrical and Computer Systems Engineering, University of Dar es Salaam.
    Mvungi, Nerey
    Faculty of Electrical and Computer Systems Engineering, University of Dar es Salaam.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Division for Electricity and Lightning Research.
    The effects of load impedance, line length, and branches in the BPLC transmission-lines analysis for-medium-voltage channel2007In: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 22, no 4, p. 2156-2162Article in journal (Refereed)
    Abstract [en]

    This paper presents the effects of load impedance, line length and branches on the performance of medium-voltage power-line communication (PLC) network. The power-line network topology adopted here is similar to that of the system in Tanzania. Different investigation with regard to network load impedances, direct line length (from transmitter to receiver), branched line length and number of branches has been investigated. From the frequency response of the transfer function (ratio of the received and transmitted signal), it is seen that position of notches and peaks in the magnitude and phase responses are largely affected in terms of attenuation and dispersion by the above said network parameters/configuration. These are observed in the time domain responses too. The observations presented in the paper could be helpful in suitable design of the PLC systems for a better data transfer and system performance.

  • 3.
    Anatory, Justinian
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Theethayi, Nelson
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Channel characterization for indoor power-line networks2009In: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 24, no 4, p. 1883-1888Article in journal (Refereed)
    Abstract [en]

    Power-line networks are promising mediums by which broadband services can be offered, such as Internet services, voice over Internet protocol, digital entertainment, etc. In this paper, an analysis of delay spread, coherence bandwidth, channel capacity, and averaged delay in the frequency bands up to 100 MHz for typical indoor power-line networks are studied. Earlier studies for indoor power-line networks considered frequencies up to 30 MHz only and earlier works have shown that at these frequency bands, the data rates are generally low and are inefficient for digital entertainment in comparison with wireless local-area networks standards, such as IEEE 802.11 n. In this paper, it is shown that at 100 MHz, the average channel capacity for typical indoor power-line networks can be up to 2 Gb/s and it is found that by increasing the number of branches in the link between transmitting and receiving ends, the average channel capacity decreases from 2 Gb/s to 1 Gb/s (when the number of branches was increased by four times for a power spectral density of -60 dBm/Hz). At the same time, the coherence bandwidth decreased from 209.45 kHz to 137.41 kHz, which is much better than the coherence bandwidths corresponding to 30-MHz systems. It is therefore recommended to operate the indoor power-line networks at 100-MHz bandwidths for a wide variety of broadband services.

  • 4.
    Anatory, Justinian
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Theethayi, Nelson
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Effects of multipath on OFDM systems for indoor broadband power-line communication networks2009In: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 24, no 3, p. 1190-1197Article in journal (Refereed)
    Abstract [en]

    Power-line networks are an excellent infrastructure for broadband data transmission. However, various multipaths within a broadband power-line communication (BPLC) system exist due to stochastic changes in the network load impedances, branches, etc. This further affects network performance. This paper attempts to investigate the performance of indoor channels of a BPLC system that uses orthogonal frequency-division multiplexing (OFDM) techniques. It is observed that when a branch is added in the link between the sending and receiving end of an indoor channel, an average of 4-dB power loss is found. Additionally, when the terminal impedances of the branch change from the line characteristic impedance to impedance of lower values, the power loss (signal-to-noise ratio) is about 0.67 dB/. On the contrary, for every increase in the terminal impedances by 100 , above the line characteristic impedance, the power loss is 0.1 dB/. When the line terminal impedances are close to short or open circuits, OFDM techniques show degraded performance. This situation is also observed when the number of branches increases. In this paper, it is shown that to overcome such performance degradation, the concatenated Reed-Solomon codes/interleaved Viterbi methods can be used. The observations presented in the paper could be useful for an efficient design of a BPLC system that uses OFDM techniques.

  • 5.
    Anatory, Justinian
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Theethayi, Nelson
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Performance of underground cables that use OFDM systems for broadband power-line communications2009In: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 24, no 4, p. 1889-1897Article in journal (Refereed)
    Abstract [en]

    Power-line networks are proposed for broadband data transmission. The presence of multipaths within the broadband power-line communication (BPLC) system, due to stochastic changes in the network load impedances, branches, etc. pose a real challenge as it affects network performance. This paper attempts to investigate the performance of an orthogonal frequency-division multiplexing (OFDM)-based BPLC system that uses underground cables. It is found that when a branch is added in the link between the sending and receiving end, there is an average of 4-dB power loss. In addition, when the terminal impedances of the branches that are connected to the link between the transmitting and receiving end vary from line characteristic impedance to low-impedance values, the power loss (signal-to-noise ratio) is about 0.35 dB/ . On the contrary, for an increase in the terminal impedances by 100 above line characteristic impedance, the power loss is 0.23 dB//. When the branch terminal impedances are close to short or open circuits, OFDM techniques show degraded performance. This situation is also observed when the number of branches increases. It is shown that to overcome degraded network performance, the concatenated Reed-Solomon codes/interleaved Viterbi methods can be used, which could be used for an efficient design of the BPLC system that uses OFDM techniques.

  • 6.
    Anatory, Justinian
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Theethayi, Nelson
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Power-line communication channel model for interconnected networks. Part I: two-conductor system2009In: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 24, no 1, p. 118-123Article in journal (Refereed)
    Abstract [en]

    This paper presents a generalized transmission-line approach to determine the transfer function of a power-line network of a two-conductor system (two parallel conductors) with distributed branches. The channel frequency responses are derived considering different terminal loads and branches. The model's time-domain behavior is validated using commercial power system simulation software called Alternative Transients Program-Electromagnetic Transients Program (ATP-EMTP). The simulation results from the model for three different topologies considered have excellent agreement with corresponding ATP-EMTP results. Hence, the model can be considered as a tool to characterize any given power-line channel topology that involves the two-conductor system. In the companion paper (Part II), the proposed method is extended for a multiconductor power-line system.

  • 7.
    Anatory, Justinian
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Theethayi, Nelson
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Power-line communication channel model for interconnected networks: Part II: multiconductor system2009In: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 24, no 1, p. 124-128Article in journal (Refereed)
    Abstract [en]

    In this paper, we present an approach to determine the transfer function for multiconductor power-line networks with distributed branches and load terminations for broadband power-line communication (BPLC) applications. The applicability of the proposed channel model is verified numerically in time domain using the finite-difference-time domain (FDTD) method for the solution of transmission lines. The channel model simulation results are in excellent agreement with the corresponding FDTD results. The model therefore could be useful in the analysis and design of BPLC systems involving multiconductor power-line topology.

  • 8.
    Anatory, Justinian
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Theethayi, Nelson
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Kissaka, M. M.
    Mvungi, N. H.
    The influence of load impedance, line length, and branches on underground cable power-line communications (PLC) systems2008In: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 23, no 1, p. 180-187Article in journal (Refereed)
    Abstract [en]

    An underground cable power transmission system is widely used in urban low-voltage power distribution systems. In order to assess the performance of such distribution systems as a low-voltage broadband power-line communication (BPLC) channel, this paper investigates the effects of load impedance, tine length, and branches on such systems, with special emphasis on power-line networks found in Tanzania. From the frequency response of the transfer function (ratio of the received and transmitted signals), it is seen that the position of notches and peaks in the magnitude are largely affected (observed in time-domain responses too) by the aforementioned network configuration and parameters. Additionally, channel capacity for such PLC channels for various conditions is investigated. The observations presented in this paper could be helpful as a suitable design of the PLC systems for better data transfer and system performance.

  • 9.
    Anatory, Justinian
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Theethayi, Nelson
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Kissaka, M.
    Mvungi, Nerey
    The effects of load impedance, line length, and branches in typical low-voltage channels of the BPLC systems of developing countries: transmission-line analyses2009In: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 24, no 2, p. 621-629Article in journal (Refereed)
    Abstract [en]

    This paper presents the influence of line length, number of branches (distributed and concentrated), and terminal impedances on the performance of a low-voltage broadband power-line communication channel. For analyses, the systems chosen are typical low-voltage power-line networks found in Tanzania. The parameters varied were the network's load impedances, direct line length (from transmitter to receiver), branched line lengths, and number of branches. From the frequency responses of the transfer functions (ratio of the received and transmitted signal), it is seen that the position of notches and peaks in the amplitude responses are affected by the aforementioned network parameters and topology. As a result, the time-domain responses are attenuated and distorted. Time-domain responses of power-line channels under various conditions are also investigated for a given pulse input at the transmitter. The observations presented in this paper could be useful for suitable power-line communication system design.

  • 10.
    Anatory, Justinian
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Theethayi, Nelson
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Kissaka, Mussa M.
    Mvungi, Nerey H.
    An experimental validation for broadband power-line communication (BPLC) model2008In: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 23, no 3, p. 1380-1383Article in journal (Refereed)
    Abstract [en]

    Recently, different models have been proposed for analyzing the broadband power-line communication (BPLC) systems based on transmission-line (TL) theory. In this paper, we make an attempt to validate one such BPLC model with laboratory experiments by comparing the channel transfer functions. A good agreement between the BPLC model based on TL theory and experiments are found for channel frequencies up to about 100 MHz. This work with controlled experiments for appropriate validation could motivate the application and extension of TL theory-based BPLC models for the analysis of either indoor or low-voltage or medium-voltage channels.

  • 11.
    Anatory, Justinian
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Theethayi, Nelson
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Kissaka, Mussa M.
    Mvungi, Nerey H.
    Broadband power-line communications: The channel capacity analysis2008In: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 23, no 1, p. 164-170Article in journal (Refereed)
    Abstract [en]

    The power line has been proposed as a solution to deliver broadband services to end users. Various studies in the recent past have reported a decrease in channel capacity with an increase-in the number of branches for a given channel type whether it is an indoor or low-voltage (LV) or medium-voltage (MV) channel. Those studies, however, did not provide a clear insight as to how the channel capacity is related to the number of distributed branches along the line. This paper attempts to quantify and characterize the effects of channel capacity in relation to the number of branches and with different terminal loads for a given type of channel. It is shown that for a power spectral density (PSD) between -90 dBm/Hz to - 30 dBm/Hz, the channel capacity decreases by a 20-30 Mb/s/branch, 14-24 Mb/s/branch, and a 20-25 Mb/s/branch for an MV channel, LV channel, and indoor channel, respectively. It is also shown that the channel capacity is minimum when the load impedance is terminated in characteristic impedances for any type of channel treated here. It is shown that there could be a significant loss in channel capacity if a ground return was used instead of a conventional adjacent conductor return. The analysis presented in this paper would help in designing appropriate power-line communication equipment for better and efficient data transfer.

  • 12.
    Anatory, Justinian
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Theethayi, Nelson
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Kissaka, Mussa M.
    Mvungi, Nerey H.
    Expressions for Current/Voltage distribution in broadband power-line communication networks involving branches2008In: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 23, no 1, p. 188-195Article in journal (Refereed)
    Abstract [en]

    Estimation of electromagnetic (EM)-field emissions from broadband power-line communication systems (BPLC) is necessary, because at its operating frequencies, the radiated emis sions from BPLC systems act as sources of interference/crosstalk to other radio-communication systems. Currently, the transmission-line (TL) system used for BPLC is complex, involving arbitrarily/irregularly distributed branched networks, arbitrary termination loads, varying line lengths, and line characteristic impedance. In order to study the electromagnetic-compatibility (EMC) issues associated with the radiated emissions of such complex BPLC networks, knowledge of current and voltage distributions along the length of the power-line channels is needed. This paper attempts to derive and present generalized expressions for either the current or voltage distribution along the line (whose TL parameters are known) between the transmitting and receiving ends for any line boundary condition and configuration based on the TL theory. The expressions presented in this paper could be beneficial for direct calculation of EM emissions from BPLC systems.

  • 13.
    Anatory, Justinian
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Division for Electricity and Lightning Research.
    Theethayi, Nelson
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Division for Electricity and Lightning Research.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Division for Electricity and Lightning Research.
    Kissaka, Mussa
    Faculty of Electrical and Computer Systems Engineering, University of Dar es Salaam.
    Mvungi, Nerey
    Faculty of Electrical and Computer Systems Engineering, University of Dar es Salaam.
    The Effects of Load Impedance, Line Length, and Branches in the BPLC—Transmission-Line Analysis for Indoor Voltage Channel2007In: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 22, no 4, p. 2150-2155Article in journal (Refereed)
    Abstract [en]

    This paper presents the effects of load impedance, line length and branches on the performance of an indoor voltage broadband power line communications (BPLC) network. The power line network topology adopted here is similar to that of the system found in Tanzania. Different investigations with regard to network load impedances, direct line length from transmitter to receiver, branched line length, and number of branches has been carried out. From the frequency response of the transfer function (ratio of the received and transmitted signal), it is seen that position of notches and peaks in the magnitude and phase responses are largely affected by the above said network parameters/configuration, mainly in terms of attenuation and dispersion. These effects are observed in the time domain responses also. The observations presented in the paper could be helpful in the suitable design of the BPLC systems for a better data transfer and system performance.

  • 14.
    Anatory, Justinian
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Theethayi, Nelson
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Mvungi, N. H.
    A broadband power-line communication system design scheme for typical Tanzanian low-voltage network2009In: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 24, no 3, p. 1218-1224Article in journal (Refereed)
    Abstract [en]

    Information and communications technologies (ICTs) are gaining importance in developing countries. Power-line network is a potential infrastructure for ICT services provision. Power-lines are highly interconnected network with stochastic variation in number of branches. Under such distributed network conditions the design of a broadband power-line communication (BPLC) system is a challenge. In this paper a case study of an actual power-line network, representative of a low-voltage BPLC channel in Dar es Salaam, Tanzania is considered. We shall investigate the performance of such a low-voltage channel that uses orthogonal frequency division multiplexing (OFDM) technique with binary phase shift keying (BPSK) modulation scheme for communication. For sensitivity analysis, three different transmitter locations were chosen and receiver points were varied to identify the possible degraded performance scenarios. Analysis show that in the frequency bands of 100 MHz, the channel delay spread for such networks is about 4 s, giving a maximum number of subchannels 4096 with 512 cyclic prefix. To improve the degraded performance scenarios, the concatenated Reed Solomon outer code with punctured convolution inner code was applied to the network. It was found that when the branches were terminated by its corresponding characteristic impedances the performance is improved by 10-20 dB compared to a corresponding uncoded system. On the contrary for a coded system when the branches were terminated either in low or higher impedances compared to branch characteristic impedances the improvement was greater than 2-15 dB. This study demonstrates that the specification proposed by IEEE-802.16 broadband wireless access working groups can be used for performance improvement of distributed low-voltage systems.

  • 15.
    Anatory, Justinian
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Theethayi, Nelson
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Mwase, C.
    Mvungi, N.H.
    The Effects of Multipath on OFDM Systems for Broadband Power-Line Communications a Case of Medium Voltage Channel2009In: World Academy of Science, Engineering and Technology, ISSN 2070-3724, Vol. 54, p. 205-208Article in journal (Refereed)
    Abstract [en]

    Power-line networks are widely used today for broadband data transmission. However, due to multipaths within the broadband power line communication (BPLC) systems owing to stochastic changes in the network load impedances, branches, etc., network or channel capacity performances are affected. This paper attempts to investigate the performance of typical medium voltage channels that uses Orthogonal Frequency Division Multiplexing (OFDM) techniques with Quadrature Amplitude Modulation (QAM) sub carriers. It has been observed that when the load impedances are different from line characteristic impedance channel performance decreases. Also as the number of branches in the link between the transmitter and receiver increases a loss of 4dB/branch is found in the signal to noise ratio (SNR). The information presented in the paper

  • 16. Baba, Y
    et al.
    Rachidi, F
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Lightning to Tall Structures, in Tutorial on EMC aspects of Lightning2007Conference paper (Other academic)
  • 17.
    Baba, Y
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. elektricitetslära och åskforskning.
    Rachidi, F
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. elektricitetslära och åskforskning.
    Thottappillill, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. elektricitetslära och åskforskning.
    Lightning to Tall Structures, in Tutorial on EMC aspects of Lightning2006Conference paper (Other academic)
  • 18. Bormann, Dierk
    et al.
    Midya, Surajit
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    DC Components in Pantograph Arcing: Mechanisms and Influence of Various Parameters2007Conference paper (Refereed)
  • 19. Bäckström, Mats
    et al.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Månsson, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Montano, Raul
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Lundén, Olof
    Nilsson, T
    Some Recent Work on Intentional EMI in Sweden2008Conference paper (Refereed)
  • 20. Flache, D.
    et al.
    Rakov, V. A.
    Heidler, F.
    Zischank, W.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Initial-stage pulses in upward lightning: Leader/return stroke versus M-component mode of charge transfer to ground2008In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 35, no 13, p. L13812-Article in journal (Refereed)
    Abstract [en]

    We analyzed high-speed video images and corresponding current records for eight upward lightning flashes initiated by the Peissenberg tower (160 m) in Germany. These flashes contained a total of 33 measurable initial stage (IS) current pulses, which are superimposed on steady IS currents. Seven IS pulses had relatively short (< , 8 mu s) 10-to-90% risetimes and 26 IS pulses had relatively long (> , 8 mu s) risetimes. Six (86%) of seven IS current pulses with shorter risetimes each developed in a newly-illuminated branch, and 25 (96%) of 26 IS pulses with longer risetimes occurred in already luminous (current-carrying) channels. These results support the hypothesis that longer risetimes are indicative of the M-component mode of charge transfer to ground, while shorter risetimes are associated with the leader/return stroke mode. Similar results were obtained for M-component pulses that are superimposed on continuing currents following return-stroke pulses.

  • 21. Lindeberg, Per Anders
    et al.
    Mazloom, Ziya
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Theethayi, Nelson
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Schutte, Thorsten
    Blitzeinwirkungen auf Oberleitungs und Signalanlagen in Schweden2007In: Eb-Elektrische Bahnen, ISSN 0013-5437, Vol. 105, no 1, p. 67-80Article in journal (Refereed)
  • 22.
    Liu, Yaqing
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Division for Electricity and Lightning Research.
    Theethayi, Nelson
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Division for Electricity and Lightning Research.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Division for Electricity and Lightning Research.
    Investigating the validity of existing definitions and empirical equations of effective length/area of grounding wire/grid for transient studies2007In: Journal of Electrostatics, ISSN 0304-3886, E-ISSN 1873-5738, Vol. 65, no 5-6, p. 329-335Article in journal (Refereed)
    Abstract [en]

    There are various definitions for effective length/area of grounding wire/grid for lightning transients [A.S. Farag, T.C. Cheng, D. Penn, Grounding terminations of lightning protective systems, IEEE Trans. Dielectics, Elect. Insul 5(6) (1998) 869–877; B.R. Gupta, B. Thapar, Impulse impedance of grounding grid, IEEE Trans. Power Apparatus Syayem PAS-99(6) (1980) 2357–2362; Y. Liu, N. Theethayi, R. Thottappillil, An engineering model for transient analysis of grounding system under lightning strikes: non–uniform transmission line approach. IEEE Trans. Power Delivery 20 (2) (2005) 722–730; M.I. Lorentzou, N.D. Hatziargriou, Modelling of long grounding conductors using EMTP, in: IPST’99, International Conference on Power System Transients, Budapest, 20–24 June, 1999; L.D. Grcev, M. Heimbach, Frequency dependent and transient characteristics of substation grounding system, IEEE Trans. Power Delivery 12 (1997) 172–178.]. The present work investigates and discusses the validity of those existing definitions. Further, practical methods for estimating the effective length/area of different grounding structures are proposed for engineering applications. The calculations for effective length/area based on non-uniform transmission line approach (Liu et al., 2005) show that, for a single grounding wire, the empirical equation for effective length in Farag et al. (1998) is not valid when the injection current has very fast rise time. Also, the empirical equation for effective length of grid edge in Gupta and Thapar (1980) is not applicable for grids with large inner mesh size.

  • 23.
    Manyahi, Mighanda
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electricity. Avdelningen för elektricitetslära och åskforskning.
    Leijon, Mats
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electricity. Avdelningen för elektricitetslära och åskforskning.
    Thottappillil, Rajeev
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electricity. Avdelningen för elektricitetslära och åskforskning.
    Transient response of transformer with XLPE insulation cable winding design2005In: International Journal of Electrical Power & Energy Systems, Vol. 27, no 1, p. 69-80Article in journal (Refereed)
    Abstract [en]

    Significant advances in XLPE insulation cables that have higher electric field strength withstand capability have made it possible to apply these high voltage (HV) cables as windings in generators and transformers. Therefore, the recent advent of HV generator (Powerformer) that can be connected directly to the power transmission line has motivated the design of HV transformer (Dryformer) that performs one step transformation from transmission to distribution voltage levels. Since the dryformer will be connected directly to transmission lines, they will be subjected to transients resulting from direct and indirect lightning strikes as well as fast switching surges from Gas insulated circuit breakers. This paper presents the results of experimental studies on the cable winding power transformer (Dryformer) to study its response to various transients. Experimental investigations have been carried to obtain the transformer model parameters based on terminal measurement of admittance functions using Network Analyser, and hence for comparing the model predictions with experimentally obtained responses. The model has been successfully used in estimating the dryformer transient responses at its terminals due to surge application of various front times and peak amplitudes that are representative of lightning and switching caused transients. Experiment and simulation results show that there are considerable differences in the transient response characteristics of dryformer windings as compared to that of transformers with traditional winding design. These differences on transient responses are discussed in perspective of their basic difference in winding design features.

  • 24.
    Manyahi, Mighanda
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electricity. Avdelningen för elektricitetslära och åskforskning.
    Thottappillil, Rajeev
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electricity. Avdelningen för elektricitetslära och åskforskning.
    Simplified model for estimation of lightning induced transient transfer through distribution transformer2005In: International Journal of Electrical Power & Energy Systems, Vol. 27, no 4, p. 241-253Article in journal (Refereed)
    Abstract [en]

    In this work a simplified procedure for the formulation of distribution transformer model for studying its response to lightning caused transients is presented. Simplification is achieved by the way with which the model formulation is realised. That is, by consolidating various steps for model formulation that is based on terminal measurements of driving point and transfer short circuit admittance parameters. Sequence of steps in the model formulation procedure begins with the determination of nodal admittance matrix of the transformer by network analyser measurements at the transformer terminals. Thereafter, the elements of nodal admittance matrix are simultaneously approximated in the form of rational functions consisting of real as well as complex conjugate poles and zeros, for realisation of admittance functions in the form of RLCG networks. Finally, the equivalent terminal model of the transformer is created as a π-network consisting of the above RLCG networks for each of its branches. The model can be used in electromagnetic transient or circuit simulation programs in either time or frequency domain for estimating the transfer of common mode transients, such as that caused by lightning, across distribution class transformer. The validity of the model is verified by comparing the model predictions with experimentally measured outputs for different types of common-mode surge waveform as inputs, including a chopped waveform that simulate the operation of surge arresters. Besides it has been verified that the directly measured admittance functions by the network analyser closely matches the derived admittance functions from the time domain impulse measurements up to 3 MHz, higher than achieved in previous models, which improves the resulting model capability of simulating fast transients. The model can be used in power quality studies, to estimate the transient voltages appearing at the low voltage customer installation due to the induced lightning surges on the high voltage side of the transformer. The procedure is general enough to be adapted for any two-port devices that behaves linearly in the frequency range of interest.

  • 25.
    Manyahi, Mighanda
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electricity. Avdelningen för elektricitetslära och åskforskning.
    Thottappillil, Rajeev
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electricity. Avdelningen för elektricitetslära och åskforskning.
    Leijon, Mats
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electricity. Avdelningen för elektricitetslära och åskforskning.
    Transfer of transient surge voltage through XLPE cable winding transformer (Dryformer) circuits2005In: Electrical Power and Energy Systems, Vol. 27, p. 602-609Article in journal (Refereed)
  • 26.
    Mazloom, Ziya
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Theethayi, Nelson
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Influence of Discrete Series Devices on Crosstalk Phenomena in Multiconductor Transmission Lines2007Conference paper (Refereed)
  • 27.
    Mazloom, Ziya
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Theethayi, Nelson
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Modeling of Passive Series Devices on Multiconductor Transmission Lines for Transient Analysis in Power and Railway Systems2008Conference paper (Refereed)
  • 28.
    Midya, Surajit
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bormann, Dierk
    Larsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Schütte, Thorsten
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Pantograph Arcing and their Consequences to Electromagnetic Interference in Railway Systems2008Conference paper (Refereed)
  • 29.
    Midya, Surajit
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bormann, Dierk
    Larsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Schütte, Thorsten
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Understanding Pantograph Arcing in Electrified Railways: Influence of Various Parameters2008Conference paper (Refereed)
  • 30.
    Midya, Surajit
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bormann, Dierk
    Mazloom, Ziya
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Schütte, Thorsten
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Conducted and Radiated Emission from Pantograph Arcing in AC Traction System2009Conference paper (Refereed)
  • 31.
    Midya, Surajit
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bormann, Dierk
    Schutte, Thorsten
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Pantograph Arcing in Electrified Railways—Mechanism and Influence of Various Parameters—Part I: With DC Traction Power Supply2009In: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 24, no Copyright 2009, The Institution of Engineering and Technology, p. 1931-9Article in journal (Refereed)
    Abstract [en]

    Pantograph arcing is a common phenomenon in electrified railway systems. This is also a source of broadband-conducted and radiated electromagnetic interference (EMI) for vehicle as well as traction power and signaling systems. In this paper and the companion paper, experimental analyses of pantograph arcing phenomena are presented for dc and ac feeding systems, respectively. Influences of different parameters on dc traction system, such as supply-voltage polarity, relative motion between pantograph and overhead contact wire, namely, forward motion along the track (longitudinal), and lateral sliding motion of the pantograph (zigzag) are presented here. From the voltage and current waveforms of the test runs, it is shown that pantograph arcing is a polarity-dependent phenomenon. For the positive-fed overhead traction system, where pantograph is cathode, the supply interruptions due to zigzag motion are comparatively less compared to negatively fed traction systems. As a result, the transients, due to pantograph arcing, are more frequent in negatively fed traction systems. It is found that the arc root movement along the electrode surfaces (pantograph-contact wire) is governed by the relative motion and polarity of the electrodes. The analyses presented in this paper also form a foundation to understand the pantograph arcing process and the corresponding influential parameters with the ac supply presented in the companion paper. The findings presented in this paper could be beneficial for coming up with appropriate mitigation techniques from the EMI due to pantograph arcing in dc-fed traction systems.

  • 32.
    Midya, Surajit
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bormann, Dierk
    Schutte, Thorsten
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Pantograph arcing in electrified railways-mechanism and influence of various parameters-Part II: with AC traction power supply2009In: IEEE Transactions on Power Delivery, ISSN 0885-8977, Vol. 24, no 4, p. 1940-50Article in journal (Refereed)
    Abstract [en]

    Pantograph arcing with AC supply generates transients, cause asymmetries and distortion in supply voltage and current waveforms and can damage the pantograph and the overhead contact line. The asymmetry generates a net dc component and harmonics, which propagate within the traction power and signalling system and causes electromagnetic interference. Unlike DC-fed systems (Part I), the arcing in ac supply is complex because of the zero crossing of currents and voltages. In this paper, we discuss the mechanisms of sliding contact and arcing between pantograph-contact wire using the experimental setup described in Part I. Influences of various parameters and test conditions on arcing phenomenon and their signature patterns on the supply voltage and current waveforms are presented. It is shown how the arcing mechanism and corresponding asymmetry in the voltage and current waveforms are governed by line speed, current, supply voltage, inductive load, and pantograph material. The asymmetry in the current waveform is mainly due to the difference in the duration of successive zero-current regions and uneven distortion of the waveshapes. This, in turn, creates the asymmetry in the voltage waveform. The findings presented in this paper could be beneficial for coming up with appropriate mitigation techniques from the electromagnetic interference due to pantograph arcing in AC traction systems.

  • 33.
    Midya, Surajit
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bormann, Dierk
    Dept of Power Technologies, ABB Corporate Research, Västerås.
    Schütte, Thorsten
    Rejlers Ingenjörer AB, Västerås.
    Thottappillil, Rajeev
    Electric Power Engineering and Design, KTH, Stockholm.
    DC Component From Pantograph Arcing in AC Traction System: Influencing Parameters, Impact, and Mitigation Techniques2011In: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, E-ISSN 1558-187X, Vol. 53, no 1, p. 18-27Article in journal (Refereed)
    Abstract [en]

    Pantograph arcing in ac traction system generates transients, and causes asymmetries and distortion in supply voltage and current waveforms. These asymmetric voltage and current lead to a net dc component and harmonics that propagate within the traction power and signalling system and cause electromagnetic interference. This problem is enhanced during winter because of the layer of ice/snow on the overhead contact wire. The sliding contact becomes poor and a visible arc moves along with the pantograph. In this paper, it is shown how different parameters like traction current, line speed, power factor, and supply voltage influence the arcing, its characteristics, and the dc components. It is shown that the dc current component increases with increasing train speed and traction current, and reduces at a lower power factor. It is also discussed how the presence of an ice layer influences the arcing and the dc components. It is found that running the trains below the normal operating power factors is an effective choice to mitigate this problem. The findings presented in this paper could be beneficial to estimate the probable limit of the dc component at the planning stage so that proper precautions can be taken at the design stage itself.

  • 34.
    Midya, Surajit
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Schütte, Thorsten
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Interaction and Interference Between AC and DC in Railway Feeding Systems2008Conference paper (Refereed)
  • 35.
    Midya, Surajit
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    An overview of electromagnetic compatibility challenges in European Rail Traffic Management System2008In: Transportation Research Part C: Emerging Technologies, ISSN 0968-090X, E-ISSN 1879-2359, Vol. 16, no 5, p. 515-534Article, review/survey (Refereed)
    Abstract [en]

    In Europe, the railway industry is rapidly getting transformed from traditional mode of public transportation to a very fast, more reliable, long distance and cross country operation. A new concept, called European Rail Traffic Management System (ERTMS) is originated to make this transition smooth, reliable and compatible among different countries. Electromagnetic interference and compatibility (EMC) issues play a major role on the overall system design and performance of this. In this paper, an overview of the operational principles and major components of ERTMS and other modern railway systems are discussed in detail with an emphasis on possible EMC issues. Radiated and conducted interferences originated from different sources and their consequences on different subsystems and components are discussed and analyzed.

  • 36.
    Midya, Surajit
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Schütte, Thorsten
    Consequences of DC Components In AC Railways and Their Elimination2007Conference paper (Refereed)
  • 37.
    Miki, M
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. elektricitetslära och åskforskning.
    Shindo, T
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. elektricitetslära och åskforskning.
    Rakov, V.A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. elektricitetslära och åskforskning.
    Uman, M.A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. elektricitetslära och åskforskning.
    Diendorfer, G
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. elektricitetslära och åskforskning.
    Mair, M
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. elektricitetslära och åskforskning.
    Heidler, F
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. elektricitetslära och åskforskning.
    Zischank, W
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. elektricitetslära och åskforskning.
    Thottappillill, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. elektricitetslära och åskforskning.
    Wang, D
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. elektricitetslära och åskforskning.
    Characterisation of current pulses superimposed on the ontinuous current in upward lightning initiated from tall objects and in rocket triggered lightning2006In: Proceedings of the 28th Internat Conference on Lightning Protection, ICLP, Kanazawa, Japan, 2006, p. 83-88Conference paper (Refereed)
  • 38. Miki, Megumu
    et al.
    Rakov, Vladimir
    Shindo, Takatoshi
    Diendorfer, Gerhard
    Mair, Martin
    Heidler, Fridolin
    Zischank, Wolfgang
    Uman, Martin
    Thottappillil, Rajeev
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electricity. Avdelningen för elektricitetslära och åskforskning.
    Wang, Daohong
    Initial stage in lightning initiated from tall objects and in rocket-triggered lightning2005In: Journal of Geophysical Research: Atmospheres, Vol. 110Article in journal (Refereed)
    Abstract [en]

    We examine the characteristics of the initial stage (IS) in object-initiated lightning derived from current measurements on the Gaisberg tower (100 m, Austria), the Peissenberg tower (160 m, Germany), and the Fukui chimney (200 m, Japan) and their counterparts in rocket-triggered lightning in Florida. All lightning events analyzed here effectively transported negative charge to ground. For rocket-triggered lightning the geometric mean (GM) values of the three overall characteristics of the initial stage, duration, charge transfer, and average current, are similar to their counterparts for the Gaisberg tower flashes and the Peissenberg tower flashes, while the Fukui chimney flashes are characterized by a shorter GM IS duration and a larger average current. The GM IS charge transfer for the Fukui chimney flashes is similar to that in the other three data sets. The GM values of the action integral differ considerably among the four data sets, with the Fukui action integral being the largest. The observed differences in the IS duration between the Fukui data set and all other data considered here are probably related to the differences in the lower current limits, while the differences in the action integral cannot be explained by the instrumental effects only. There appear to be two types of initial stage in upward lightning. The first type exhibits pulsations (ringing) during the initial portion of the IS, and the second type does not. The occurrence of these types of IS appears to depend on geographical location. The characteristics of pulses superimposed on the initial continuous current (ICC pulses) in object-initiated (Gaisberg, Peissenberg, and Fukui) lightning are similar within a factor of 2 but differ more significantly from their counterparts in rocket-triggered lightning. Specifically, the ICC pulses in object-initiated lightning exhibit larger peaks, shorter risetimes, and shorter half-peak widths than do the ICC pulses in rocket-triggered lightning.

  • 39.
    Montaño, Raul
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bäckström, Mats
    Månsson, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    On the Response and Immunity of Critical Infrastructures Against IEMI – Current Swedish Research Initiatives2008Conference paper (Refereed)
  • 40.
    Montaño, Raul
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bäckström, Mats
    Månsson, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Response and Immunity of Electric Power Infrastructure Against IEMI – Ongoing Swedish Initiatives2008Conference paper (Refereed)
  • 41.
    Månsson, Daniel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Lundén, Olof
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bäckström, Mats
    The scenario of intentionally radiated electromagnetic interference to railway systems2007Conference paper (Refereed)
  • 42.
    Månsson, Daniel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Nilsson, Tony
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bäckström, Mats
    Propagation of UWB Transients in Low-Voltage Installation Power Cables2007In: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, E-ISSN 1558-187X, Vol. 49, no 3, p. 585-592Article in journal (Refereed)
    Abstract [en]

    This paper investigates the propagation of subnanosecond rise time (ultra wideband) voltage transients in low-voltage installation power cables. Experimental results are compared to simulations. It is concluded that the main mode of propagation of differentially injected transients in low-voltage installation power cables is transverse electromagnetic mode. Also, such transients would spread relatively unattenuated to any load or junction in the power system, received power primarily only limited by the impedance mismatches causing reflections. The effects of different types of bends in the cable have been studied. The study was conducted as a part of an assessment of the susceptibility of civilian facilities to intentional electromagnetic interference.

  • 43.
    Månsson, Daniel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. elektricitetslära och åskforskning.
    Nilsson, Tony
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. elektricitetslära och åskforskning.
    Thottappillill, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. elektricitetslära och åskforskning.
    Bäckström, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. elektricitetslära och åskforskning.
    Susceptibility of GPS Receivers and Wireless Cameras to a single Radiated UWB Pulse2006In: proceedings of EMC, Barcelona, Spain, 2006Conference paper (Refereed)
  • 44.
    Månsson, Daniel
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electricity. Avdelningen för elektricitetslära och åskforskning.
    Thottappillil, Rajeev
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electricity. Avdelningen för elektricitetslära och åskforskning.
    Comments on "Linear and Nonlinear Filters Suppressing UWB Pulses"2005In: IEEE Transactions on Electromagnetic Compatibility, Vol. 47, no 3, p. 671-672Article in journal (Refereed)
    Abstract [en]

    In a recently presented paper, different surge protective devices' response to conducted UWB pulses are investigated. However, it is shown here that some of the results for varistors presented in that paper are due only to the packaging and not to the surge protective element in itself.

  • 45.
    Månsson, Daniel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    The Threat of Conducted High Power Electromagnetic Pulses in Civilian Facilities2007Conference paper (Refereed)
  • 46.
    Månsson, Daniel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bäckström, Mats
    Methodology for Classifying Facilities with respect to Intentional EMI2009In: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, E-ISSN 1558-187X, Vol. 51, no 1, p. 46-52Article in journal (Refereed)
    Abstract [en]

    It is argued that it is the intent behind the electromagnetic interference in intentional electromagnetic interference (IEMI) that causes problems to large distributed systems and facilities even if   they are designed by traditional zoning concept rules. Hardening such   facilities against IEMI requires a correspondence between the electromagnetic zone boundary and the physical access control boundary. The three characteristics of a facility, the accessibility, susceptibility, and consequence, are discussed in the context of vulnerability to IEMI. A methodology for classification of facilities

  • 47.
    Månsson, Daniel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bäckström, Mats
    Propagation Ability of UWB Transients through Junctions of Low-voltage Power Installation Cable2008In: 2008 ASIA-PACIFIC SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY AND 19TH INTERNATIONAL ZURICH SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY, VOLS 1 AND 2, 2008, p. 279-282Conference paper (Refereed)
    Abstract [en]

    It has been shown earlier 121 that Ultra Wide Band (UWB) transients can travel in differential mode (DM) along low voltage power installation cables, and deliver large amounts of power to connected equipments. However, branches in the network were not included at that time. In this paper, the ability of UWB transients to propagate through different types of junctions of low voltage power cables is investigated. The received voltage could with very good accuracy be estimated from Transmission Line Theory, either using theoretical calculations or numerical simulations. This was verified experimentally. The decrease in voltage received at the loads of the branches is mainly due to the reflection caused by impedance mismatch at the junction. It is concluded that large voltages can be delivered to unprotected loads, if a UWB transient is injected in DM at another part of the same network.

  • 48.
    Månsson, Daniel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bäckström, Mats
    Propagation of UWB transients in low-voltage power installation networks2008In: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, E-ISSN 1558-187X, Vol. 50, no 3, p. 619-629Article in journal (Refereed)
    Abstract [en]

    In this paper, the propagation of ultra-wideband (UWB) transients through different types of junctions of low-voltage power cables and one real power network of a building were investigated. For the laboratory test, it was seen that the main mode of propagation in the cables and through the junctions tested is transverse electromagnetic (TEM). The received voltage could thus be, within a small error, estimated from transmission-line theory. The main cause for decreased voltage received at the loads of the branches of the junctions is reflections due to impedance mismatch of the junctions. Large voltages can be delivered to many unprotected loads connected to the junctions. UWB transients were also injected into a residential house using a power outlet available on the outside wall of the house. It was seen that the complexity of this network creates deviation from the TEM mode. However, relatively large voltages were still received at the various outlets inside the house. It is recommended that power outlets or lamp sockets outside buildings are controlled from inside using two-pole switches that reduce the received voltage to reduce the risk of conducted intentional electromagnetic interference.

  • 49.
    Månsson, Daniel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bäckström, Mats
    Lundén, Olof
    Vulnerability of European Rail Traffic Management System to Radiated Intentional EMI2008In: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, E-ISSN 1558-187X, Vol. 50, no 1, p. 101-109Article in journal (Refereed)
    Abstract [en]

    In this paper, the vulnerability of the future electrified railway system in Europe from a high-power microwave (HPM) source is investigated. The scenario of in-band disturbances radiated toward a GSM-R antenna and damaging the connected communications system is evaluated for different classes of HIM sources and situations. The minimum realistic distances for the different HPM sources from the antenna to cause permanent damage is shown, and the severity of threat from the different sources is discussed.

  • 50.
    Månsson, Daniel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thottappillil, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Nilsson, Tony
    Lundén, Olof
    Bäckström, Mats
    Susceptibility of Civilian GPS Receivers to electromagnetic radiation2008In: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, E-ISSN 1558-187X, Vol. 50, no 2, p. 434-437Article in journal (Refereed)
    Abstract [en]

    Civilian handheld global positioning system receivers were tested for their susceptibility against radiated electromagnetic disturbances of different characteristics and field levels. This susceptibility data were compared to the existing electromagnetic compatibility (EMC) immunity requirements for electronic devices. Some of the receivers were disrupted by continues waves at in-as well as out-of-band frequencies, at field levels far below the existing EMC requirements. The possible reason for this is discussed. In general, due to the ever-growing use of commercial-off-the-shelf equipment even for critical functions, certificates of conformity to current EMC requirements may be inadequate.

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