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  • 1.
    Espin Delgado, Angela
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Propagation of Supraharmonics in Low-Voltage Networks2022Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The need for measures towards a sustainable use of energy has incited the proliferation of devices and systems for the efficient use of electricity. Energy-efficient appliances, equipment for the electrification of transportation, electricity generators from renewable energy sources, and communication protocols, e.g., for smart metering are sources of supraharmonic distortion in electrical networks. Supraharmonics are voltage and current waveform distortion in the frequency range from 2 up to 150 kHz.

    The increase in sources of supraharmonics in the last decades and the propagation of this type of distortion have triggered a variety of unwanted consequences (interference) in the electrical networks. Interference associated to supraharmonics such as audible noise, degradation or failure in the operation of electrical equipment, and breakdown of insulation materials, have been reported around the world. A standardized framework for supraharmonics as a power quality phenomenon that involves both grid operators and equipment manufacturers is needed to limit these interferences. The limits to be set shall not hinder the modernization of the electrical system and the consequential energy transition.

    There are gaps in the standardization framework for supraharmonics as a power quality phenomenon. The study of supraharmonics as a power quality parameter should consider variables that affect emission levels and propagation of supraharmonics. At the same time, an assessment of the severity of given supraharmonics levels regarding their consequences is needed to settle realistic reference levels. Deterministic methods have been generally used to study supraharmonic propagation but they might not be suitable when considering many possible scenarios.

    This research introduces forefront methods and results on the study of supraharmonics emission, propagation, and consequences. The study has two focal points: 1) to study the impact of the impedance of the grid and low-voltage devices on the emission and propagation of supraharmonics; 2) to assess the severity of propagated supraharmonics in terms of the characteristics of the distortion and the probability of interference. Experimental and theoretical case studies are built to carry out the research. Measured and synthetic signals representative of supraharmonic distortion present in low-voltage networks are used.

    The main results of this research are summarized as:

    The levels of emitted and propagated supraharmonics depend on the impedance of the grid, the emitting device and the neighboring devices. Resonance can lead to significant levels of supraharmonics anywhere in the grid. The variability and diversity of low-voltage devices lead to high uncertainty in the estimation of their impedance. Stochastic methods are recommended to assess the probability of interference.

    Different attributes of supraharmonics are responsible for different interference phenomena. Indications of the severity of supraharmonics attributes are given for three phenomena: audible noise, negative impacton residual current devices, and light flicker of LED lamps.

    This research contributes to the establishment of supraharmonics as a power quality phenomenon with standardized solutions. It introduces methods for the assessment of: 1) supraharmonic emission from installations needed to recommend planning levels; 2) supraharmonic propagation in low-voltage networks, and 3) the probability of interference needed to define reference levels.

    Fulltekst (pdf)
    fulltext
  • 2.
    Espin Delgado, Angela
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Camarillo-Penaranda, Juan Ramón
    Universidad de los Andes, Bogota, Colombia.
    Ramos, Gustav
    Universidad de los Andes, Bogota, Colombia.
    Characterization of Phase-Angle Jump in RadialSystems using Incremental Voltage Phasors2019Inngår i: IEEE transactions on industry applications, ISSN 0093-9994, E-ISSN 1939-9367, Vol. 55, nr 2, s. 1117-1125Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A methodology for characterizing the phase-angle jump associated with voltage sags in radial systems using incremental voltage quantities is presented in this paper. The incremental voltage phasor is defined as the difference between the pre-fault and the during-fault voltage phasors at the point of common coupling. The characteristics of this phasor are stated for different fault conditions as a function of system impedances. Both fault impedance and source neutral grounding impedance are considered in the analysis. Furthermore, the vector representation of phasors and impedance diagrams are employed as a graphical aid for understanding the incremental quantities behavior as a function of the system parameters. An algorithm for fault classification is also presented. Finally, the theoretical analysis is confirmed using real data provided by the Department of Energy and the Electric Power Research Institute. The results of this paper can be useful in future works for fault classification and fault location.

  • 3.
    Espin Delgado, Angela
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Assessment of Grid Impedance Impact On Supraharmonic Propagation2021Inngår i: CIRED 2021 - The 26th International Conference and Exhibition on Electricity Distribution, Institution of Engineering and Technology, 2021, s. 688-692, artikkel-id 0073Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Supraharmonic (SH) propagation is determined by the impedance of both the grid and the devices connected to it. Few attempts to characterize this combined dependency have been done. The interest of grid operators is in counteracting the propagation of SHs upstream to maintain power quality. Characterizing the impact of impedance on SH propagation gives information to strategically counteract this propagation to the upstream grid. This paper presents an experimental case study for the assessment of the sensitivity of SH propagation to changes in impedance of the grid at the delivery point. The results are then compared to the changes of SH propagation provoked by the connection of low-voltage (LV) equipment.

  • 4.
    Espin Delgado, Angela
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Modeling and Analysis of Supraharmonic Propagation for Stochastic Studies2022Inngår i: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 37, nr 6, s. 4899-4910Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Supraharmonic (SH) propagation depends on the impedance of both the grid and the devices connected to it. Few attempts to quantify the impact of the customer's load variability have been done. The interest of grid operators is in counteracting the SH propagation upstream to maintain power quality. Quantifying the impact of impedance on supraharmonic propagation gives information to strategically counteract this propagation to the grid. This article presents a method for analysis of SH propagation that uses a stochastic approach to describe the impact of low-voltage (LV) loads. Scenarios of a strong and a weak grid are presented to study the impact of reinforcement grid measures.

  • 5.
    Espin Delgado, Angela
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Busatto, Tatiano
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Ravindran, Vineetha
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Summation law for supraharmonic currents (2–150 kHz) in low-voltage installations2020Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 184, artikkel-id 106325Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The development of methods to study the propagation of supraharmonics in LV and even MV grids is a current research topic among the power quality community, which has been motivated by the efforts to establish limits for non-intentional supraharmonic emissions and planning levels. The assessment of how much distortion a bulk use of power electronics devices can inject into the grid is necessary before stating emission limits and planning levels for supraharmonics. To address this issue, the development of suitable models that can predict the supraharmonic emission from a low-voltage installation as a whole is required. This article presents a comparison of models for the summation of supraharmonics. An improved model for the summation of supraharmonics is proposed, which is validated experimentally. It is shown that by using the proposed model, predictions of supraharmonic propagation can be accomplished. Furthermore, it is demonstrated experimentally that, with the increasing number of supraharmonic emitting devices, the supraharmonic current distortion injected into a grid by an installation increases up to a maximum value and then decreases due to the capacitive nature of power electronics appliances existing in low-voltage networks.

  • 6.
    Espin Delgado, Angela
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Sutaria, Jil
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    de Oliveira, Roger Alves
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Application of Clustering and Dimensionality Reduction Methods for Finding Patterns on Supraharmonics Data2022Inngår i: 2022 20th International Conference on Harmonics & Quality of Power (ICHQP) Proceedings: “Power Quality in the Energy Transition”, IEEE, 2022Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Supraharmonics (waveform distortion between 2 and 150 kHz) proliferate in electrical installations due to the increasing use of power electronics converters and power-line communication. Due to the wide range that the supraharmonics cover and the high frequency resolution needed to measure them, a considerable amount of data is acquired. The analysis is usually done manually by experts. More efficient methods for data mapping and analysis are needed. Machine learning methods are explored in this paper for the analysis of supraharmonics data.

  • 7.
    Espin Delgado, Angela
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Sutaria, Jil
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Nakhodchi, Naser
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Impact of Supraharmonics and Quasi-dc On the Operation of Residual Currentdevices2021Inngår i: CIRED 2021 - The 26th International Conference and Exhibition on Electricity Distribution, Institution of Engineering and Technology, 2021, s. 668-672, artikkel-id 60Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Residual current devices (RCDs) are used in low voltage installations to disconnect the circuit in case of fault when the leakagecurrent exceeds a reference magnitude. The magnitude of reference leakage current is based on the magnitude of current thathuman body can withstand without getting shocked. This reference current is defined based on the 50/60 Hz component in theleakage current. The use of power electronic converters that switch in the supraharmonics frequency range (2 to 150 kHz) andrenewable energy sources such as solar inverters, would lead to the leakage current consisting of different frequencycomponents. This paper studies the impact of quasi-dc (0-4 Hz) and supraharmonics on the tripping characteristics of differenttypes of RCDs with the aim to identify fail-to-trip and false tripping conditions.

  • 8.
    Espín-Delgado, Angela
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Busatto, Tatiano
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Ravindran, Vineetha
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah K.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Meyer, Jan
    Power Quality Research Group, Technische Universität Dresden, Dresden, Germany .
    Evaluation of Supraharmonic Propagation in LV Networks Based on the Impedance Changes Created by Household Devices2020Inngår i: Proceedings of 2020 IEEE PES Innovative Smart Grid Technologies Europe (ISGT-Europe) 26-28 October, 2020, IEEE, 2020, s. 754-758Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper investigates the characteristics of emission in the frequency range 2-150 kHz (supraharmonics) in time and frequency domain and how it propagates under different scenarios posed by the customer connections and changes in the grid. The analysis is based on measurements performed in a low-voltage installation, considering the simultaneous operation of a set of PV inverters and LED lamps in order to create changes in both impedance and emissions. The results confirm that supraharmonics tend to interact with nearby devices in the customer installation. As the number and constellation of emitting devices change so does the propagation of the supraharmonics. The propagation towards the grid can either increase or decrease with the increasing number of connected devices depending on the ratio between the impedances of the device and the grid impedance. Devices’ technology plays an important role in defining supraharmonic characteristics, emission levels and propagation. Finally, a qualitative analysis of the individual devices’ impedance and discussion of some of the practical aspects is provided.

  • 9.
    Espín-Delgado, Angela
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sara K.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math H. J.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Uncertainties in the Quantification of Supraharmonic Emission: Variations over Time2020Inngår i: PAPERS0 ICREPQ'20, European Association for the Development of Renewable Energies, Environment and Power Quality (EA4EPQ) , 2020, artikkel-id 208Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper shows a study of the variations of the supraharmonic distortion emitted by an LED lamp during and after its thermal stabilization. The study is aimed to contribute to map the uncertainties existing when quantifying supraharmonics. Measurements of the current drawn by five lamps of the same type and manufacturer are performed. Then, analysis in the frequency domain is performed and the Total Supraharmonic Current (TSHC) index is used to quantify the supraharmonic emission of the lamps. The TSHC is calculated over bands of different widths, whose outcomes are then compared to decide which bandwidth results in a less time-varying-TSHC index. It is demonstrated that the supraharmonic distortion emitted by the lamp under study experiences both an increase in magnitude and a shift in frequency during the thermal stabilization of the lamp. It is also shown how the frequency grouping impacts the quantification. It is concluded that the best choice of a grouping bandwidth is one wide enough so that it includes the whole emission band of interest. This result is a step forward to set up references for the analysis and quantification of broadband supraharmonic emission.

  • 10.
    Espín-Delgado, Ángela
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Sudha Letha, Shimi
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Diagnosis of supraharmonics-related problems based on the effects on electrical equipment2021Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 195, artikkel-id 107179Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Supraharmonics (SH) have proliferated in low-voltage (LV) and medium-voltage (MV) grids due to the increasing use of technologies emitting distortion in the range 2–150 kHz. Currently, no recommended practices to assess the effects of SH on the electrical system exist. The propagation of SH through LV and MV grids leads to interference with the elements for power delivery and end-user equipment, e.g., light flicker, aging of capacitors and cable terminations, audible noise, and interruption of electric vehicle (EV) charging. As such incidents happen more often, the need for guidelines that facilitate the diagnosis of problems related to SH arises. Different features of the SH distortion are responsible for different interferences. This article introduces guidelines for the evaluation of the impact of SH based on the morphology of the interference. The evaluation is performed with easy-to-use methods and formulas directly related to the characteristics of the SH distortion. The adverse effects of SH considered are audible noise, light flicker, tripping of LV residual current devices (RCDs), and MV cable termination failure. This work interests field engineers and researchers facing problems related to SH; it also serves as a guide for further research.

  • 11.
    Espín-Delgado, Ángela
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Sudha Letha, Shimi
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah K.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math H. J.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Failure of MV Cable Terminations due to Supraharmonic Voltages: A Risk Indicator2020Inngår i: IEEE Open Journal of Industry Applications, E-ISSN 2644-1241, Vol. 1, s. 42-51Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper addresses the accelerated aging of medium-voltage (MV) cable terminations with resistive stress-grading due to supraharmonics. The paper introduces a simple and quick way to relate the risk of cable termination failure to the characteristics of supraharmonic distortion in the system. The motivation is to give practical recommendations and guidelines to evaluate the risk of failure of cable terminations under the presence of supraharmonics in MV networks. The underlying model relates the heating in the cable termination linearly with the frequency of the voltage applied and proportionally with the square of the magnitude of the voltage. The indicator can be used to decide whether given levels and frequencies of supraharmonics in the MV network represent a risk to cable terminations. The parameters of the cable termination design are not needed for that decision. However, the decision criterion is based on one sample data (Eagle Pass) and more field information is crucial to improve the approach.

  • 12.
    Nakhodchi, Naser
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Espin Delgado, Angela
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Deviation From Linear Summation Law For Large Number of Homogeneous LED Lamps2021Inngår i: CIRED 2021 - The 26th International Conference and Exhibition on Electricity Distribution, Institution of Engineering and Technology, 2021, s. 683-687, artikkel-id 0072Konferansepaper (Fagfellevurdert)
  • 13.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Gil de Castro, Aurora
    University of Cordoba, Spain.
    Espin Delgado, Angela
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Variations of supraharmonic emissions in low voltage networks2019Inngår i: CIRED 2019 Conference, AIM , 2019, artikkel-id 5Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper describes and presents measurements of supraharmonic emission in low voltage grids in Europe, North America and Asia. One-minute average values for 2 kHz grouped components are given and a total supraharmonic distortion (TSHD) value is calculated for the frequency band 2 to 150 kHz. Statistical analyses are performed, investigating the site and time dependency of supraharmonic voltages. Results show that the average values are, with a 90% confidence within an interval of 0.09-0.56% of fundamental (FND) but higher values can occur. Based on analyses of these measurements some early conclusions can be drawn:

    Supraharmonic emission are present in low voltage grids

    The magnitudes and frequencies vary between sites and over time

    There is a daily pattern but also some randomness when supraharmonics appear.

  • 14.
    Sudha Letha, Shimi
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. Electrical Engineering Department, Punjab Engineering College (Deemed-to-be University), Chandigarh, 160012, India.
    Bollen, Math H. J.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Busatto, Tatiano
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Espin Delgado, Angela
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Mulenga, Enock
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bakhtiari, Hamed
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Sutaria, Jil
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Uddin Ahmed, Kazi Main
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Nakhodchi, Naser
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Sakar, Selçuk
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Ravindran, Vineetha
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Power Quality Issues of Electro-Mobility on Distribution Network—An Overview2023Inngår i: Energies, E-ISSN 1996-1073, Vol. 16, nr 13, artikkel-id 4850Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    The journey towards sustainable transportation has significantly increased the grid penetration of electric vehicles (EV) around the world. The connection of EVs to the power grid poses a series of new challenges for network operators, such as network loading, voltage profile perturbation, voltage unbalance, and other power quality issues. This paper presents a coalescence of knowledge on the impact that electro-mobility can impose on the grid, and identifies gaps for further research. Further, the study investigates the impact of electric vehicle charging on the medium-voltage network and low-voltage distribution network, keeping in mind the role of network operators, utilities, and customers. From this, the impacts, challenges, and recommendations are summarized. This paper will be a valuable resource to research entities, industry professionals, and network operators, as a ready reference of all possible power quality challenges posed by electro-mobility on the distribution network.

    Fulltekst (pdf)
    fulltext
  • 15.
    Sudha Letha, Shimi
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Espin Delgado, Angela
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah K.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math H. J.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Evaluation of Medium Voltage Network for Propagation of Supraharmonics Resonance2021Inngår i: Energies, E-ISSN 1996-1073, Vol. 14, nr 4, artikkel-id 1093Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Power converters with high switching frequency used to integrate renewable power sources to medium and low voltage networks are sources of emission in the supraharmonic range (2 to 150 kHz). When such converters are connected to a medium voltage (MV) network these supraharmonics propagate through the MV network and can impact network and customer equipment over a wide range. This paper evaluates an existing Swedish MV electrical network and studies the pattern of supraharmonic resonance and the propagation of supraharmonics. The MV network consists of eight feeders including a small wind farm. Simulations reveal that, the bigger the MV network, the more resonant frequencies, but also the lower the amplitude of the resonance peaks in the driving point impedance. It was also identified that for short feeders as length increases, the magnitude of the transfer impedance at supraharmonic frequency decreases. For further increment in feeder length, the magnitude increases or becomes almost constant. For very long feeders, the transfer impedance further starts decreasing. The eight feeders in the network under study are similar but show completely different impedance versus frequency characteristics. Measurements at the MV side of the wind farm show time varying emissions in the supraharmonic range during low power production. The impact of these emissions coupled with system resonance is examined.

    Fulltekst (pdf)
    fulltext
  • 16.
    Sutaria, Jil
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Espin Delgado, Angela
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Measurements and modeling of the frequency behavior of residual current devices- from 4 Hz to 40 kHz2022Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 209, artikkel-id 108052Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Residual current devices (RCDs) are a common means of protection against shock due to indirect contact in low voltage (LV) systems. Due to the increasing penetration of power electronics equipment in LV systems, higher amounts of waveform distortion at a broad range of frequencies, from dc, subharmonics up to hundreds of kHz (supraharmonics), are expected to be present both during normal operation and during faults. The standardization committees and manufacturers have responded to this challenge by proposing different types of RCDs that are expected to function under given conditions of fault current waveform. However, subharmonic and supraharmonic frequency components are not considered in the standards for most of the RCD types. This article studies the effect of these frequency components on RCDs type AC, A, B and F. An assessment is made in terms of two types of RCD failure: blinding and nuisance tripping, for which both magnitude of the current and breaking time is considered. A frequency mapping of the RCDs is performed, and an assessment of these results based on the frequency-dependent response of the human body to currents is performed. Finally, a frequency model for RCDs type A, F and B is developed.

  • 17.
    Sutaria, Jil
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Espin Delgado, Angela
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Supraharmonics within a Datacenter-Emission and Propagation2022Inngår i: 2022 20th International Conference on Harmonics & Quality of Power (ICHQP) Proceedings: “Power Quality in the Energy Transition”, IEEE, 2022Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The reliability of the electrical and cooling systems is of utmost importance for the uninterrupted operation of the data center information technology (IT) load. The electrical distribution of the data center includes many subsystems starting with the utility and building transformers, uninterruptible power supply (UPS), power distribution units (PDUs), and power supplies ultimately powering the fans and the internal components of IT equipment. The various converters in data centers emit switching frequency residue due to PWM (pulse width modulation) techniques. The switching frequency range falls within the supraharmonic range, i.e., 2 to 150 kHz. This paper aims to show, with measurements, the different types of supraharmonic emissions measured in the data center, and the difference between their maximum and average magnitudes. The paper shows a method to identify the equipment emitting supraharmonic emission and possible disturbances caused by it. The paper traces the propagation of supraharmonic emission from the source through the transformer to the grid. Lastly, a comparison of measurements is made with the compatibility levels given by standard IEC 61000-2-2.

  • 18.
    Sutaria, Jil
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Espín-Delgado, Angela
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Summation of Supraharmonics in Neutral for Three-Phase Four-Wire System2020Inngår i: IEEE Open Journal of Industry Applications, E-ISSN 2644-1241, Vol. 1, s. 148-156Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Due to the increase in electronic loads such as LED lamps, power supply units for computing loads, voltage frequency drives in industries; high-frequency distortion is introduced into the power system. These high-frequency components appear due to the switching components of different power electronic converters present in the mentioned loads. The switching frequency components are most often in the range of 2 kHz to 150 kHz referred to as supraharmonics. The paper aims to show, with simulations and measurements, how supraharmonics sum in neutral and to quantify the neutral supraharmonic current as a ratio of single-phase current. This paper defines characteristics of supraharmonic emission that influence their summation in the neutral conductor through studies of devices connected in a balanced three-phase four-wire system. The paper further defines the relation of the supraharmonics emission with the number of devices connected at each phase. A mathematical model to predict the supraharmonics in a neutral conductor based on single-phase current and the number of devices further proposed.

  • 19.
    Sutaria, Jil
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Espin Delgado, Angela
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Factors influencing the induced primary emission and induced secondary emission in the frequency range of 2 to 150 kHz2023Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 224, artikkel-id 109725Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The induced primary emission leads to changes in the primary emission of a device and the induced secondary emission leads to changes in the propagation of supraharmonics in the adjacent phase due to the connection of single-phase loads spread over three phases in an installation. The induced primary emission and induced secondary emission are shown to give a significant contribution to the total emission measured at a given point in an installation. The induction of the emission is caused by the inductive and capacitive coupling among the conductors within the cables. This paper presents an analysis of four parameters that impact the magnitude of the induced emissions. Simulations carried out in COMSOL, show that the type of cable used impacts the induced emission and studies show that shielded cable with a stranded conductor with the shield grounded will lead to a reduction in the induced emissions. Among the other parameters, i.e., the load and transformer impedance and the length of the cable, the length of the cable is dominating in deciding the magnitude of the induced emissions. Analysis is carried out using Monte Carlo simulation and varying parameters stochastically. For all investigated parameters there is a strong frequency dependency. The stochastic variation of the load impedance in one phase causes a variation of 5% whereas the change in length of the cable leads to a maximum 40% variation in the considered frequency range for induced primary emission. Measurement results are presented to validate the results.

    Fulltekst (pdf)
    fulltext
  • 20.
    Sutaria, Jil
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Espín-Delgado, Ángela
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Analysis of supraharmonics in a three-phase frame2022Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 203, artikkel-id 107668Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Interaction in the supraharmonic range of 1-ϕ device connected in 1-ϕ or 3-ϕ installations will differ according to the design of the installation. Power factor corrected devices employing switched mode power supplies produce supraharmonics in the range 2–150 kHz. The impact of e.g. voltage unbalance, load unbalance and conductor crosstalk on supraharmonics from these devices connected in a 3-ϕ installation are still somewhat unknown. The paper aims to show with measurements and mathematical models the impact of voltage unbalance, load unbalance, and conductor crosstalk on supraharmonics. The impact of voltage unbalance for constant power loads was seen to increase the emission of supraharmonics. Two new terms induced primary and induced secondary emission showing the impact of conductor crosstalk have been introduced. The induced primary emission leads to an increase in the self-emission of the device. The induced secondary emission on the other hand influences the propagation of the emission. The impact of the voltage unbalance, load unbalance, and conductor crosstalk on the addition of supraharmonics emission in the neutral conductor is shown.

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