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  • 251. Macken, K.J.P
    et al.
    Wallace, I.T
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Reliability assessment of motor drives2006Ingår i: 37th IEEE Power Electronics Specialists Conference, PESC '06: 18 - 22 June 2006, [Jeju, Jeju, Korea], Piscataway, NJ: IEEE Communications Society, 2006, s. 1-7Konferensbidrag (Refereegranskat)
    Abstract [en]

    Electric motor drives have seen widespread adoption in many applications. Motor drives reliability has become a driving factor for potential customers whose process up time and power availability are crucial to their business success. Reliability is therefore a key driver in power circuit design for these applications. Two commonly used approaches available to designers to assess the reliability of motor drives are detailed in this paper. The first approach is a failure mode and effect analysis (FMEA). This approach is used to identify and list those component failures and combinations of component failures that result in an interruption of operation. The second approach is a so-called calculation of reliability indices which is performed to quantify the reliability of the system and verify that the design requirements are met. A case study of a redundant multilevel motor drive for multi-mega watt gas compression systems is given to illustrate both approaches

  • 252. Martinez, J A
    et al.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Voltage dip evaluation and prediction tools2009Ingår i: ELECTRA, ISSN 1286-1146, nr 242, s. 67-72Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A voltage dip is a sudden reduction of the voltage below a specified threshold followed by its recovery after a brief interval, which can cause problems on sensitive equipment. The TB introduces the subject of voltage dips and their characterisation, equipment behaviour and mitigation techniques. Furthermore, a review is given of simulation tools and calculation methods that can be used for voltage dip assessment.

  • 253.
    Meyer, Jan
    et al.
    TU Dresden, Institute of Electrical Power Systems and High Voltage Engineering.
    Blanco, Ana Maria
    TU Dresden, Institute of Electrical Power Systems and High Voltage Engineering.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Smith, Jeff W.
    Electric Power Research Institute (EPRI), Power System Studies, Palo Alto, CA.
    CIGRE C4/C6.29: Survey of utilities experiences on power quality issues related to solar power2017Ingår i: CIRED - Open Access Proceedings Journal, ISSN 2515-0855, Vol. 2017, nr 1, s. 539-543Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Owing to the energy policies and the consequent transition to renewable energy sources, the amount of photovoltaic (PV) installations is continuously increasing in many countries. As PV inverters utilise power electronics, its impact on power quality is an important concern for manufacturers, planners, solar power operators and utilities/ network operators. The International council on large electric systems (CIGRE) working group C4/C6.29 has studied many aspects related to PV installations and its impact on power quality. To incorporate the existing experiences with power quality issues related to solar power, an international survey has been conducted by the working group. The survey has found that there is a significant lack of information among utilities/network operators with respect to the possible impact of PV installations on power quality. It is recommended to intensify the monitoring of PV installations in order to obtain sufficient information for a reliable assessment of its impact on power quality.

  • 254.
    Meyer, Jan
    et al.
    Technical University Dresden.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Amaris, Hortensia
    University Carlos III, Madrid.
    Blanco, Ana María
    Technical University Dresden.
    Castro, Aurora Gil de
    University of Cordoba.
    Desmet, Jan
    Ghent University, Kortrijk.
    Klatt, Matthias
    Technical University Dresden.
    Kocewiak, Lukasz
    DONG Energy Wind Power, Fredericia.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Yang, Kai
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Future work on harmonics: some expert opinions part II – supraharmonics, standards and measurements2014Ingår i: International Conference on Harmonics and Quality of Power. Proceedings: , Proceedings - International Conference on Harmonics and Quality of Power, ISSN 1540-6008, s. 909-913, artikel-id 6842871Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A workshop on power system harmonics was organized in Stockholm in January 2014. On the agenda was among others a discussion on what are the main issues on harmonics at the moment and in the near future. Some of the issues discussed at that workshop are presented in this paper and its companion paper. In this paper the following issues will be addressed: the appearance of emission at higher frequencies (supraharmonics); the need for new and improved standards; measurement issues and data analysis

  • 255.
    Milanovic, J. V.
    et al.
    School of Electrical and Electronic Engineering, The University of Manchester.
    Meyer, J.
    Institute of Electrical Power Systems and High Voltage Engineering, Technische Universitaet Dresden.
    Ball, R. F.
    National Grid, Warwick Technology Park, Warwick.
    Howe, W
    Electric Power Research Institute (EPRI), Boulder, CO.
    Preece, R.
    School of Electrical and Electronic Engineering, The University of Manchester.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Elphick, S.
    Australian Power Quality and Reliability Centre, University of Wollongong.
    Čukalevski, N.
    Institue “Mihailo Pupin,” Belgrade.
    International Industry Practice on Power Quality Monitoring2014Ingår i: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 29, nr 2, s. 934-941Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Monitoring of voltages and currents at system buses gives the network operators information about the performance of their network, both for the system as a whole and for individual locations and customers. There is also demand from the customers and the regulatory agencies to provide information on the actual power-quality (PQ) level. Developments in enabling technology have made it possible to monitor at a large scale and to record virtually any PQ parameter of interest. While many network operators are installing monitoring equipment and while more and more monitors are available, there is a lack of knowledge and agreement on a number of aspects of the monitoring process and on processing the recorded data. As a response to this lack of uniformity in approach, data acquisition, and processing, in February 2011, CIGRE and CIRED established the Joint Working Group C4.112: “Guidelines for Power quality monitoring—measurement locations, processing and presentation of data.” In order to identify the current international industry practice on PQ monitoring, the group carried out a survey in 43 countries across the world. This paper summarizes the key findings from 114 responses to the questionnaire and identifies prevalent industrial practice in PQ monitoring around the world.

  • 256.
    Milanovic, Jovica V.
    et al.
    University of Manchester, School of Electrical and Electronic Engineering, The University of Manchester.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Cukalevski, Ninel
    Mihailo Pupin Institute.
    Guidelines for monitoring power quality in contemporary and future power networks – results from CIGRE/CIRED JWG C4.1122014Konferensbidrag (Refereegranskat)
  • 257.
    Morena-Garcia, Isabel
    et al.
    University of Cordoba.
    Gil-de-Castro, Aurora
    University of Cordoba.
    Gu, Irene
    Chalmers University of Technology.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Tests and Analysis of a novel Segmentation method using Measurement Data2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    Fault detection in power systems and its diagnosis are highly relevant issues within a power quality scope. Detailed analysis of disturbance recordings, like voltage dips, requires accurate segmentation methods. A joint causal and anti-causal (CaC) segmentation method has been introduced but only been tested with synthetic signals. In this paper, its performance has been analysed with a set of real measurement signals.

  • 258.
    Moreno, Isabel
    et al.
    University of Cordoba.
    Moreno, Antonio
    University of Cordoba.
    Gil de Castro, Aurora
    University of Cordoba.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Gu, I.Y.H.
    Chalmers University of Technology.
    Causal and anti-causal segmentation of voltage dips in power distribution networks2016Ingår i: IEEE Latin America Transactions, ISSN 1548-0992, E-ISSN 1548-0992, Vol. 14, nr 7, s. 3080-3086Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents the performance of a joint causal and anti-causal (CaC) segmentation method for automatic location of nonstationary parts of power quality (PQ) events. Accurate time allocation of events and sequences of events is an important study to automatically analyze disturbances in the future (smart) grid. The new method developed is based on the cumulative sum (CUSUM) algorithm and is applied to a wide set of power quality events to analyze its performance. The main advantage of CaC segmentation is that the location in time of underlying transitions in the power system is accurately estimated.

  • 259.
    Moreno-Garcia, Isabel M.
    et al.
    University of Cordoba, Electronics and Electronic Technology Area, University of Cordoba.
    Moreno-Munoz, Antonio
    University of Cordoba, Electronics and Electronic Technology Area, University of Cordoba.
    Gil-de-Castro, Aurora
    University of Cordoba, Electronics and Electronic Technology Area, University of Cordoba.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Gu, Irene Y.H.
    Chalmers University of Technology.
    Novel technique for segmentation of measured three-phase voltage dips2015Ingår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 8, nr 8, s. 8319-8338Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper focuses on issues arising from the need to automatically analyze disturbances in the future (smart) grid. Accurate time allocation of events and the sequences of events is an important part of such an analysis. The performance of a joint causal and anti-causal (CaC) segmentation method has been analyzed with a set of real measurement signals, using an alternative detection technique based on a cumulative sum (CUSUM) algorithm. The results show that the location in time of underlying transitions in the power system can be more accurately estimated by combining CaC segmentation methods.

  • 260.
    Moreno-Munoz, Antonio
    et al.
    University of Cordoba.
    Gil-de-Castro, Aurora
    University of Cordoba.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Romero-Cadaval, E.
    Supraharmonics (2 to 150 kHz) and multi-level converters2015Ingår i: 5th IEEE International Conference on Power Engineering, Energy and Electrical Drives: POWERENG 2015, Riga, Latvia, 11-13 May 2015, Piscataway, NJ: IEEE Communications Society, 2015, s. 37-41, artikel-id 7266293Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper summarizes the state of part of the discussions in CIGRE/CIRED/IEEE joined working group C4.24, especially where it concerns supraharmonics. There is an increasing interest from the international standard-setting community in knowledge about distortion in the frequency range 2 to 150 kHz, referred to as supraharmonics. The reduction of emission in the lower-frequency ranges appears to result in an increase in supraharmonic emission by equipment. Power electronics has emerged as a ubiquitous technology, which plays a critical role in almost any areas. Power electronics converter is an important source of waveform distortion, but, as shown in this paper, power electronics can also be the key to mitigate distortion, when the proper technology is employed.

  • 261.
    Moreno-Munoz, Antonio
    et al.
    University of Cordoba.
    Gil-de-Castro, Aurora
    University of Cordoba.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Romero-Cadval, Enrique
    University of Extramadura.
    Ongoing work in CIGRE working groups on supraharmonics from power-electronic converters2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper summarizes the state of part of the discussions in CIGRE/CIRED joined working group C4.24, especially where it concerns supraharmonics. There is an increasing interest from the international standard-setting community in knowledge about distortion in the frequency range 2 to 150 kHz, referred to as supraharmonics. The reduction of emission in the lower-frequency ranges appears to result in an increase in supraharmonic emission by equipment. Power electronics has emerged as a ubiquitous technology, which plays a critical role in almost any areas. Power electronics converter is an important source of waveform distortion, but, as shown in this paper, power electronics can also be the key to mitigate distortion, when the proper technology is employed.

  • 262.
    Mozsolics, Alexandra
    et al.
    HEO.
    Birinyi, Zsolt
    HEO.
    Zmijarevic, Zlatko
    HERA.
    Vailati, Riccardo
    AEEG.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Friedl, Werner
    E-Control.
    Commercial quality regulation in European countries2013Ingår i: 22nd International Conference and Exhibition on Electricity Distribution (CIRED 2013): Stockholm, Sweden, 10 - 13 June 2013, Red Hook, NY: Curran Associates, Inc., 2013, artikel-id 561Konferensbidrag (Refereegranskat)
    Abstract [en]

    The Council of European Energy Regulators has been publishing Benchmarking Reports on the Quality of Electricity Supply since 2001 on a regular basis. For the 5th edition of the Benchmarking Report the 29 member countries of CEER were joined by the 9 NRA's from the Energy Community and the NRA from Switzerland. This paper contains the main results, findings and recommendations on commercial quality from this latest edition of the Benchmarking Report.

  • 263.
    Mulenga, Enock
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Impact of Service and Feeder Cable Upgrade on Hosting Capacity for Single Phase Connected Photovoltaics2018Ingår i: Proceedings of International Conference on Harmonics and Quality of Power, ICHQP, Institute of Electrical and Electronics Engineers (IEEE), 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    The addition of photovoltaics (PV) to a grid impacts the performance of that grid in a number of ways. These impacts limit how much PV can be connected, termed ‘hosting capacity (HC)’. The impacts include overvoltage and overloading. Mitigation of impacts can be achieved in different ways: in this paper, upgrade of service cable and feeder cable has been considered, one of the classical solutions. Cable size upgrades to 16, 25 and 35 mm2 from 10 mm2 have been studied to mitigate overvoltages in a 28-customer Swedish suburban grid. A stochastic planning-based approach has been used to obtain a performance parameter that can be used to compare the mitigation methods. The results showed an improvement in overvoltage and hosting capacity with cable upgrade. The hosting capacity is also shown to be sensitive to the risk chosen and to the PV size.

  • 264.
    Mulenga, Enock
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Etherden, Nicholas
    Vattenfall R & D, Vattenfall AB, Sweden.
    A review of hosting capacity quantification methods for photovoltaics in low-voltage distribution grids2020Ingår i: International Journal of Electrical Power & Energy Systems, ISSN 0142-0615, E-ISSN 1879-3517, Vol. 115, artikel-id 105445Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A literature review is presented in this paper of the methods for quantifying the solar PV hosting capacity of low-voltage distribution grids. Three fundamentally different methods are considered: i) deterministic ii) stochastic iii) time series. The methods’ outline of applications, merits and shortfalls are summarized. The methods differ in the input data, accuracy, accuracy, computation time, consideration of uncertainties, consideration of the time-related influence and the models used. Two types of uncertainties need to be considered: certain (aleatory) uncertainties and uncertain (epistemic) uncertainties. The latter ones are only included in some of the stochastic methods.

    In most of the reviewed publications, the voltage magnitude rise and increased loading with increased risk of overvoltage and overloading (for lines, cables and transformers) were the main phenomena considered in the hosting capacity study.

    This review offers guidelines for distribution system planners on which hosting-capacity method to be used and to researchers on research gaps.

  • 265.
    Mulenga, Enock
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Etherden, Nicholas
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. Vattenfall AB.
    Overvoltage due to single-phase and three-phase connected PV2019Ingår i: 25th International Conference on Electricity Distribution, Madrid, 3-6 June 2019., CIRED - Congrès International des Réseaux Electriques de Distribution, 2019, s. 1-5, artikel-id No 370Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents the overvoltage caused by single and three-phase connected PV to a low-voltage distribution grid. Statistics are obtained based on source-impedance data for 40 000 customers. A stochastic approach is applied to a 28-customer low-voltage network and the probability of overvoltage is assessed. It is shown that the voltage rise due to single-phase connected PV is six times the rise for three-phase connected PV.To mitigate the overvoltage, grid-reinforcement, reactive power compensation, curtailment and coordinated connection of PV can be used. It is shown that reactive compensation is not effective in LV grids due to high R/X ratio. Coordinated connection helps in reducing the overvoltages caused by single-phase PV.Policy suggestions towards three-phase PV installations and coordinated single-phase PV connections are included in the paper.

  • 266.
    Mulenga, Enock
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Etherden, Nicholas
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. Vattenfall AB.
    The Role of Aleatory and Epistemic Uncertainties in a Stochastic Hosting Capacity Approach for Solar PV2019Ingår i: IEEE PES Innovative Smart Grid Technologies (ISGT), Bucharest: IEEE, 2019, s. 1-5, artikel-id 133Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper introduces the terms aleatory and epistemic uncertainties for use in a stochastic hosting capacity method. The role these uncertainties play in the hosting capacity determination is illustrated. It is shown that distinction between aleatory (statistical) and epistemic (systematic) uncertainties is helpful to characterize the probability distributions correctly. For epistemic uncertainties, it is often challenging to obtain information on the probability distribution function. For aleatory uncertainties, a method for characterizing the probability distribution is presented. Aleatory uncertainties’ data measurements are used to obtain a distribution best-fit. The background voltage measurement for a customer in a low-voltage distribution network is used to illustrate the method. Values were obtained for the distribution functions of the three-phase voltages. The used distribution functions are found to influence the resulting hosting capacity. This entails that there is need for measurements and data collection. A research challenge remaining concerns the stochastic model of epistemic uncertainty.

  • 267.
    Nunez, V Barrera
    et al.
    IIiA Research Institute, University of Girona, Spanien.
    Gu, Irene
    Chalmers University of Technology, Department of Signals and Systems.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Meléndez, J.
    IIiA Research Institute, University of Girona, Spanien.
    Feature characterization of power quality events according to their underlying causes2010Ingår i: 14th International Conference on Harmonics and Quality of Power (ICHQP), Piscataway, NJ: IEEE Communications Society, 2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper addresses the problem of extracting effective features for the analysis of underlying causes of power quality (PQ) disturbances. For each underlying cause, we define and extract a set of features based on analysis of voltage/current waveforms or the combination of them. The proposed feature sets are then used for building a rule-based classification framework for automatic identification of the underlying causes stored in PQ databases. These rules are based on the extracted features. Using the proposed features and rules, the proposed classifier has yielded a correct classification rate of 95.8% for a total of 96 disturbance sequences, demonstrating a high accuracy distinguishing between the different underlying causes in PQ events.

  • 268.
    Nömm, Jakob
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    An Analysis of Frequency Variations and its Implications on Connected Equipment for a Nanogrid during Islanded Operation2018Ingår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, artikel-id en11092456Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Frequency, voltage and reliability data have been collected in a nanogrid for 48 weeks during islanded operation. Frequency values from the 48 week measurements were analyzed and compared to relevant limits. During 19.5% of the 48 weeks, the nanogrid had curtailed the production due to insufficient consumption in islanded operation. The curtailment of production was also the main cause of the frequency variations above the limits. When the microgrid operated on stored battery power, the frequency variations were less than in the Swedish national grid. 39.4% of all the interruptions that occurred in the nanogrid are also indirectly caused by the curtailment of solar production. Possible solutions for mitigating the frequency variations and lowering the number of interruptions are also discussed.

  • 269.
    Nömm, Jakob
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    An analysis of voltage quality in a nanogrid during islanded operation2019Ingår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 12, nr 4, artikel-id 614Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Voltage quality data has been collected in a single house nanogrid during 48 weeks of islanded operation and 54 weeks of grid-connected operation. The voltage quality data contains the voltage total harmonic distortion (THD), odd harmonics 3 to 11 and 15, even harmonics 4 to 8, voltage unbalance, short-term flicker severity (Pst) and long-term flicker severity (Plt) values, and voltage variations at timescales below 10 min. A comparison between islanded and grid-connected operation values was made, were some of the parameters were compared to relevant grid standard limits. It is shown that some parameters exceed the defined limits in the grid-standards during islanded operation. It was also found that the islanded operation has two modes of operation, one in which higher values of the short circuit impedance, individual harmonic impedance, harmonic voltage distortion and voltage unbalance were reached.

  • 270.
    Nömm, Jakob
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Harmonic Voltage Measurements in a Single House Microgrid2018Ingår i: Proceedings of International Conference on Harmonics and Quality of Power, ICHQP, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    The harmonic voltage distortion have been measured in a single house microgrid in Sweden. The microgrid can operate in both islanded mode and grid connected mode. A comparison of the voltage harmonic magnitudes has been made between the two operation states and also against relevant standards. Both the 10 minute average and the 3 second average values are presented in the paper. The harmonic voltage magnitudes are higher during island mode and the difference between the 10 minute value and 3 second value is also greater compared to when the microgrid is connected to the grid. At some instances the magnitudes of both total harmonic distortion and of individual harmonics exceed the limits described in the standards.

  • 271.
    Olguin, G
    et al.
    Department of Electric Power Engineering, Chalmers University of Technology.
    Vuinovich, F
    Department of Electrical Engineering, University Palermo.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    An optimal monitoring program for obtaining voltage sag indices2006Ingår i: IEEE Transactions on Power Systems, ISSN 0885-8950, E-ISSN 1558-0679, Vol. 21, nr 1, s. 378-384Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a meter placement method for voltage sags monitoring in large transmission systems. An integer programming-based modeling is proposed for choosing the locations of power quality meters. A branch-and-bound-type algorithm is used to solve the optimization problem. A large transmission network is used to validate the method. Stochastic assessment of voltage sags is applied to the test network to obtain simulated monitoring results. Voltage sags system indexes are calculated from monitoring programs designed according to the optimization method. Comparisons with the system indexes obtained from a full monitoring program show the applicability of the method.

  • 272.
    Oliveira, Thiago Cle de
    et al.
    Universidade Federal de Itajubá.
    Filho, Jose Maria de Carvalho
    Universidade Federal de Itajubá.
    Leborgne, Roberto Chouhy
    Universidade Federal do Rio Grande do Sul.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Voltage sags: validating short-term monitoring by using long-term stochastic simulation2009Ingår i: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 24, nr 3, s. 1344-1351Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a procedure to validate voltage sag results based on a short-term monitoring program and stochastic assessment of voltage sag characteristics. The main practical use of this methodology is to analyze the accuracy of sag characteristics obtained from short monitoring periods. With a Monte Carlo Simulation approach, probabilistic models of several factors are taken into account: lines and busbars fault rate, pre-fault voltage, fault-type distribution, fault-location uncertainty, and fault resistance distribution. Confidence intervals based on the percentile method and hypothesis tests are the statistical tools selected to perform the validation of voltage sags magnitude and frequency. A case study based on the evaluation of a six-month monitoring period shows the applicability of the proposed methodology.

  • 273. Pinares, G
    et al.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Understanding the operation of HVDC grids2011Konferensbidrag (Refereegranskat)
  • 274.
    Ravindran, Vineetha
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Busatto, Tatiano
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Comparison of a non-parametric and parametric method for interharmonic estimation in PV systems2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    A comparative analysis of ‘Desynchronized processing technique’ (non-parametric) and ‘Sliding window ESPRIT method’ (parametric) for interharmonic estimation in PV systems is carried out. Both methods were applied to field measurements and semi-measured signals to test their feasibility under different conditions. In Desynchronized processing technique, in the second stage of estimation, a Short-term Fourier transform was used to address the time-varying nature of interharmonics. In Sliding window ESPRIT method, the signal subspace dimension was fixed in all analysed cases. An adaptive algorithm was used to find the best rank of the Hankel matrix and apt order of the filter to ensure stability. A set of critical parameters affecting the performance of these methods in interharmonic estimation are identified. This paper emphasizes the significance of using appropriate methods for accurate interharmonic estimation and also demonstrates through the illustrated results that different inferences can be drawn for the same measurements analysed using different methods.

  • 275.
    Ravindran, Vineetha
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Busatto, Tatiano
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Meyer, Jan
    Technische Universität, Dresden, Germany.
    Charactizations of interactions between PV and Energy efficient lighting (LED) in a mixed installation.2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    The possible interactions between grid-tied powerelectronicbased PV systems and energy efficient LEDlighting systems in terms of current and voltage, fordifferent combinations of the inverter and LED lamp typesunder different grid conditions, are studied in a laboratoryenvironment. In this paper, the interactions arecharacterized in terms of the power quality disturbanceslike harmonics, interharmonics, supraharmonics,overvoltage, undervoltage, and rapid voltage changes.

  • 276.
    Ravindran, Vineetha
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Busatto, Tatiano
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Meyer, Jan
    Institute of Electrical Power Systems and High Voltage Engineering, Technische Universitaet Dresden, Dresden, Germany.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Time-varying interharmonics in different types of grid-tied PV inverter systems2019Ingår i: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Widely existing circuit topologies and inverter control strategies for PV systems allow customer flexibility but also introduce different kinds of interharmonics into the grid. A complete understanding of interharmonics from PV systems, with reasons behind their origin, remains needed. In addition, the timevarying nature of interharmonics and the potential impacts on other equipment are yet to be understood. In this paper, laboratory and field measurements are presented of seven different inverter types at multiple locations. A comprehensive analysis is performed to understand the existence, persistence, and propagation of interharmonics in PV systems on the DC side as well as grid side for different power levels. The origins of the interharmonics are established with experimental evidence and through a comparative analysis. A rural low voltage 6 customer network, with two different impedance profiles caused by the installation of PV, is considered to show the potential impact on customer voltage. To address the time-varying nature of interharmonics, a sliding window ESPRIT method is preferred over FFT based methods

  • 277.
    Ravindran, Vineetha
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Interharmonics in PV systems: A Review of analysis and estimation methods; considerations for selection of an apt method2019Ingår i: IET Renewable Power Generation, ISSN 1752-1416, E-ISSN 1752-1424, Vol. 13, nr 12, s. 2023-2032Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    A comprehensive reviewing of existing interharmonic analysis and estimation methodologies irrespective of application is carried out. The paper is enlisting the characteristics of an appropriate method to analyse and estimate interharmonics in PV systems, and linking these characteristics with the features of the reviewed methodologies. The distinctive characteristics of interharmonic emissions related to PV systems are therefore presented. The various methodologies are classified, summarized, and a checklist is prepared to emphasize the areas to be paid attention to while establishing an apt method for interharmonic analysis in PV systems. The priorities for selection of a method by a practicing engineer vary case by case. This paper will serve as a guideline for selection and further development of a suitable method for interharmonic analysis in a PV included power system.

  • 278.
    Ravindran, Vineetha
    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.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Inspection of Interharmonic emissions from a Grid-tied PV Inverter in North Sweden2018Ingår i: Proceedings of International Conference on Harmonics and Quality of Power, ICHQP, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    The main objective of the paper is to investigate theexistence of interharmonic emissions from an MPPT drivengrid-connected PV inverter, identify their severity andpersistence. The presence of interharmonics in the measuredcurrent from a PV installation is linked to direct and diffusedsolar irradiation as well as a high ramping rate of theirradiation causing variations in both active and reactive power.The paper sets forth a set of observations and inferences, whichis an appendage to the ongoing research on the power qualityaspects of solar power. Three different case studies areevaluated in detail using signal processing tools like STFT andFFT.

  • 279.
    Renders, B,
    et al.
    Electrical Energy Laboratory (EELAB), Department of Electrical Energy, Systems and Automation (EESA), Ghent University.
    Vandevelde, L.
    Electrical Energy Laboratory (EELAB), Department of Electrical Energy, Systems and Automation (EESA), Ghent University.
    Degroote, L.
    Electrical Energy Laboratory (EELAB), Department of Electrical Energy, Systems and Automation (EESA), Ghent University.
    Stockman, K.
    Provinciale Industriële Hogeschool, Hogeschool West-Vlaanderen, Kortrijk.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Distributed generation and the voltage profile on distribution feeders during voltage dips2010Ingår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 80, nr 12, s. 1452-1458Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The presence of distributed generators in the distribution network results in an increase of the voltage magnitude close to these generators, during a fault elsewhere in the distribution system or in the transmission system. This voltage dip mitigation capability of converter-connected distributed generation (DG) units is dependent on the control strategy of the converter. To compare the influence of different types of converter-connected distributed generators on the voltage profile along distribution feeders during a fault, the quantity,"voltage ratio" is used. This voltage ratio is obtained by division of the voltage during the voltage dip by the voltage just before the voltage dip. The different converter types are modelled, and the influence on the voltage ratio is analysed.

  • 280.
    Renders, Bert
    et al.
    Department of Electrical Energy, Systems and Automation (EESA), Ghent University.
    Gussemé, Koen De
    Department of Electrical Energy, Systems and Automation (EESA), Ghent University.
    Ryckaert, Wouter
    Department Industrieel Ingenieur, Katholieke Hogeschool Sint-Lieven, Ghent.
    Stockman, Kurt
    Department Provinciale Industriële Hogeschool, Hogeschool West-Vlaanderen, Kortrijk.
    Vandevelde, Lieven
    Department of Electrical Energy, Systems and Automation (EESA), Ghent University.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Distributed generation for mitigating voltage dips in low-voltage distribution grids2008Ingår i: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 23, nr 3, s. 1581-1588Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The presence of synchronous and induction generators has a positive effect on the retained voltage (the lowest rms voltage during the event) during voltage dips in high voltage networks. The impact of converter-connected distributed-generation (DG) units has been reported to be negligible, as most converters operate at unity power factor, and the currents injected in the grid are limited to the nominal current of the converter. However, the impact of DG units on the distorted grid voltage is strongly dependent on the voltage level, and thus the grid impedance, of the concerned grid. This paper investigates and compares the effects of converter-based DG units, synchronous and asynchronous generators on the retained voltage during voltage dips in low voltage distribution grids.

  • 281.
    Ruwaida, Yvonne
    et al.
    Vattenfall Distribution.
    Holmberg, David
    Vattenfall.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Mapping of harmonic levels in the low-voltage network2015Konferensbidrag (Refereegranskat)
  • 282.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Emission from four types of LED lamps for frequencies up to 150 kHz2012Ingår i: 15th International Conference on Harmonics and Quality of Power (ICHQP), IEEE Communications Society, 2012, s. 451-456Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper shows the results of measurements performed on a quantity of different light emitting diode based energy saving lamps (LED's).

  • 283.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Estimating system indices for short interruptions from data obtained by a limited number of monitors2017Ingår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 146, s. 63-70Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents an estimation of the number of monitoring locations needed to get an accurate estimation of system indices for short interruptions. The study uses data from 11 Swedish distribution network operators, where the number of short interruptions is available for every single costumer. The error range in the estimated system parameters is obtained as a function of the number of monitor locations by obtaining mean and spread of the estimations from 10 000 randomly-selected sets of monitor locations.

    To obtain a rough estimation of the system average or 95-percentile (error margin less than 50%), about 200 monitors are needed. For system 99-percentile, about 400 monitors are needed. For a reasonably accurate estimation, with an error margin less than 10%, a few thousand monitors are needed for both system average and system 95-percentile. Several thousand monitors are needed for the system 99-percentile. The paper also presents some system statistics for the 11 distribution network operators and compares the requirements with recommendations given by the Council of European Energy Regulators.

  • 284.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Measurements of primary and secondary emission in the supraharmonic frequency range, 2-150 kHz2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents an analysis of current emission from low-voltage devices in the frequency range from 2 to 150 kHz. Measurements on an installation with a photovoltaic (PV) inverter together with common household appliances are presented. It is shown to be important to distinguish between emission driven by a certain device (“primary emission”) and emission driven by other devices (“secondary emission”). Measurements show that primary emission can be strongly impacted by neighbouring devices. Moreover it is shown that supraharmonic currents flow between connected appliances and measurements of supraharmonic distortion should be performed on site, inside the installation.

  • 285.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Power quality issues in the electric power system of the future2016Ingår i: Electricity Journal, ISSN 1040-6190, E-ISSN 1873-6874, Vol. 29, nr 10, s. 49-61Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    With the advent of new electricity production modes, power electronics, LED lamps and underground cables, new types of disturbances will appear, including an increase in distortion between 2 kHz and 150 kHz that is referred to as ‘supraharmonics.’ A shift of resonances to lower frequencies may partly compensate for the increased emissions at higher frequencies, but the transfer of disturbances will become less predictable. Equipment immunity also is likely to become less predictable.

  • 286.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Solar power in northern Scandinavia, its impact on the grid and methods to mitigate this impact2013Ingår i: 2013 4th IEEE/PES Innovative Smart Grid Technologies Europe (ISGT EUROPE): Copenhagen, Denmark, 6-9 Oct 2013, Piscataway, NJ: IEEE Communications Society, 2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents results from measurements of solar-power production in the north of Scandinavia; studies of the impact on the grid when larger amounts of solar power are installed, and methods to mitigate this grid impact. It is shown that solar power has limited contribution to reducing the peak loading of the grid. Large amounts of solar power will even increase the peak loading. Curtailment is shown to be an appropriate way of allowing more solar energy to be injected into the grid without additional grid investment. It is important however to use the right control method (“soft curtailment”) as otherwise production will decrease with increasing installed capacity. It is also shown in the paper that unacceptable voltage variations can occur when large installations are connected to weak parts of the grid. The availability of hourly metering data is an important contribution to integration studies.

  • 287.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Solar power plants in the north of Europe: Power quality, hosting capacity and smart solutions to increase the hosting capacity2013Rapport (Övrigt vetenskapligt)
  • 288.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Amaris, Hortensia
    University Carlos III, Madrid.
    Chang, Gary W.
    National Chung Cheng University, Taiwan.
    Gu, Irene Y.H.
    Chalmers University of Technology.
    Kocewiak, Łukasz Hubert
    DONG Energy Wind Power, Fredericia.
    Meyer, Jan Christian
    Technische Universitaet Dresden.
    Olofsson, Magnus
    Swedish Energy Institute.
    Ribeiro, Paulo F.
    Federal University of Itajubá, Brazil.
    Desmet, Jan
    Gent University, Campus Kortrijk.
    On waveform distortion in the frequency range of 2 kHz–150 kHz: Review and research challenges2017Ingår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 150, s. 1-10Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The frequency range between 2 and 150 kHz has recently gained significant attention, triggered by standardization needs and increased emission in this wide frequency range. This paper gives an overview of the state-of-the-art concerning these so-called supraharmonics, and noticeably indicates the research challenges associated with waveform distortion in this frequency range, with emphasis on the following aspects: emission; propagation; interference; measurements; standardization; modelling and simulation.

  • 289.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Gil-de-Castro, Aurora
    University of Cordoba.
    Harmonic distortion from energy-efficient equipment and production in the low-voltage network2014Rapport (Övrigt vetenskapligt)
  • 290.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Langella, Roberto
    Department of Industrial and Information Engineering, University of Campania "Luigi Vanvitelli".
    Zavoda, Francisc
    IREQ, Varennes.
    Hasler, Jean-Philippe
    ABB Substations, Västerås.
    Ciufo, Philip
    University of Wollongong.
    Cuk, Vladimir
    Eindhoven University of Technology.
    Meyer, Jan Christian
    Technische Universitaet Dresden.
    The expected impact of four major changes in the grid on the power quality: a review2017Ingår i: Cigre Science & Engineering, ISSN 2426-1335, Vol. 8, s. 5-13Artikel i tidskrift (Refereegranskat)
  • 291.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Larsson, Anders
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Emission from small scale PV-installations on the low voltage grid2014Ingår i: The Renewable Energies and Power Quality Journal (RE&PQJ), ISSN 2172-038X, E-ISSN 2172-038X, nr 12, artikel-id 427Artikel i tidskrift (Refereegranskat)
  • 292.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Larsson, Anders
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Grid impact from PV-installations in northern Scandinavia2013Ingår i: 22nd International Conference and Exhibition on Electricity Distribution (CIRED 2013): Stockholm, Sweden, 10 - 13 June 2013, Red Hook, NY: Curran Associates, Inc., 2013, artikel-id 1036Konferensbidrag (Refereegranskat)
    Abstract [en]

    The use of solar panels is becoming more popular in Sweden. Parts of Scandinavia have many sun hours and the cold temperatures are advantageous as they lead to higher efficiencies and longer lifetimes of the solar cells. Except during the darkest time of the year (Nov-Feb) PV is a suitable complement for power production also in the northern parts of Scandinavia, especially when using a proper tracking system In this paper power quality issues concerning the connection of photovoltaic systems will be discussed. Emission up to 25 kHz will be presented as well as voltage variations caused by the production. Measurements from three phase connected plants (20 kW) and from smaller (up to 2.5 kW) single phase connected plants are shown. The harmonic emission from PV-plants is reasonable low and somewhat constant with regards to the production. Some residue from the switching of the inverter can be found typical at a few kHz.

  • 293.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Larsson, Anders
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lundmark, Martin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    An overview of the origin and propagation of Supraharmonics (2-150 kHz)2014Konferensbidrag (Refereegranskat)
  • 294.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Larsson, Anders
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Emission from different types of energy efficient lamps at frequencies up to 150 kHz2012Konferensbidrag (Refereegranskat)
  • 295.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Nömm, Jakob
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Power Quality measurements in a single house microgrid2017Ingår i: CIRED - Open Access Proceedings Journal, ISSN 2515-0855, Vol. 2017, nr 1, s. 818-822Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Power quality measurements have been performed during 1 year in a small-scale microgrid in Sweden. The microgrid consists of one residential house that can operate in grid-connected or grid-disconnected (islanded) modes. During the year the microgrid was disconnected from the main grid most of the time.

  • 296.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Wahlberg, Mats
    Power quality issues due to electronic lighting2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    With the interest to reduce electrical energy consumption there is an upcoming shift from the traditional incandescent lamps to more energy efficient types of lighting. This has raised a concern of a possible adverse effect on the power grid as we replace a resistive load with an electronic one. The main concerns include harmonic distortion, losses in the grid, and displacement power factor (cos ). A set of measurements have been made in order to determent how a shift in lamps would affect a number of power quality parameters. The measurements have been conducted on a typical household base load consisting of a mix of lamps, TV, computers, heat and kitchen equipment. The measurements have been performed in the laboratory so as to have complete control over the load. A typical consumption pattern has been defined however so as to make the measurements both realistic and reproducible. In the initial stage the installation contains only incandescent lamps; in the final stage all incandescent lamps are replaced with a more energy efficient alternative. A second set of measurements have been made in a medium size hotel, with a load of over 500 incandescent lamps. The power quality has been monitored before, during and after all the lamps were replaced by 40 W equivalent LED lamps. This paper will focus on harmonic distortion up to 9 kHz as well as the affect a shift in lamps will have on the displacement power factor and on losses in the distribution grid.

  • 297.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Gil de Castro, Aurora
    Electronics Technology, University of Cordoba.
    Moreno-Muñoz, Antonio
    University of Cordoba.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Garrido, Joaquin
    University of Cordoba.
    Solar PV inverter supraharmonics reduction with random PWM2017Ingår i: 2017 11th IEEE International Conference on Compatibility, Power Electronics and Power Engineering, CPE-POWERENG 2017, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2017, s. 644-649, artikel-id 7915248Konferensbidrag (Refereegranskat)
    Abstract [en]

    The international standardization community is currently reviewing the supraharmonics distortion limits. These are harmonics which fall in the frequency range 2 to 150 kHz. Power electronics has consolidated as a ubiquitous technology, which also plays a critical role in this subject. Broadly speaking, these HF components are due to the normal operation of electronic converters and the switching techniques employed. The paper presents measurements of waveform distortion from several illustrative facilities and loads. Recent studies indicate that future problems to distribution grids may include supraharmonics. Grid-tie inverters are an origin of waveform distortion, still in this frequency range, but, can also be the pillar to mitigate it, when methodologies like random pulse with modulation or modular multilevel converter are properly applied

  • 298.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Gil-de-Castro, Aurora
    University of Cordoba.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Moreno-Munoz, Antonio
    University of Cordoba.
    Romero-Cavadal, Enrique
    University of Extremadura, Badajoz.
    Supraharmonics from Power Electronics Converters2015Ingår i: 9th International Conference on Compatibility and Power Electroncis (CPE 2015): Costa da Caparica, 24-26 June 2015, Piscataway, NJ: IEEE Communications Society, 2015, s. 539-544Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper summarizes the state of part of the discussions in CIGRE/CIRED/IEEE joined working group C4.24, especially where it concerns supraharmonics. There is an increasing interest from the international smart grid standard-setting community in knowledge about harmonics distortion in the frequency range 2 to 150 kHz, referred to as supraharmonics. The paper presents measurements of waveform distortion from several illustrative installations and loads. The reduction of emission in the lower-frequency ranges appears to result in an increase in supraharmonic emission by equipment. Power electronics has emerged as a ubiquitous technology, which plays a critical role in almost any areas. Power electronics converter is an important source of waveform distortion, but, as stated in this paper, power electronics can also be the key to mitigate distortion, when the proper technology is employed.

  • 299.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Larsson, Anders
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Schanen, Jean-Luc
    Grenoble Electrical Engineering Lab.
    A simple model for interaction between equipment at a frequency of some tens of kHz2011Ingår i: Proceedings of CIRED 21st International Conference on Electricity Distribution, 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a simple model to explain the spread of high-frequency current between different devices and into the grid. The model is also used to show the aggregation between devices. The model is used to predict the amplitude modulation of the voltage and current ripple due to the small frequency differences between devices. The results from the model confirm earlier measurement results.

  • 300.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lundmark, Martin
    Andersson, Marcus
    Luleå tekniska universitet.
    Larsson, Anders
    Bollen, Math
    Wahlberg, Mats
    Skellefteå Kraft AB.
    Attenuation and noise level: potential problems with communication via the power grid2007Ingår i: Conference proceedings: 19th International Conference and Exhibition on Electricity Distribution : Vienna, 21 - 24 May 2007, Liege: AIM , 2007, artikel-id 0186Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper will give examples of the potential problems associated with remote-meter reading via the power grid and describe some of the technologies available. Examples will be given of practical cases in which the communication channel does not function in the intended way. Three potential problems with communication via the power grid are identified in the paper:The noise level is too high for the information to reach the receiverThe attenuation at the frequencies used for communication is too high. Several cases have been identified where this made communication impossible. Certain types of end-user equipment cause a large attenuation of the communication signal, so that a too small amount of the signal reaches the receiverInterference with other equipment. A flicker problem was found due to a modulated 100-Hz signal used for communication

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