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  • 1.
    Alvarez Perez, Manuel Alejandro
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bermúdez, Juan
    Department of Energy Conversion and Transport, Simón Bolívar University.
    Zhong, Jin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Reservoir-Type Hydropower Equivalent Model Based on a Future Cost Piecewise Approximation2018Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 155, s. 184-195Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The long-term (LT) scheduling of reservoir-type hydropower plants is a multistage stochastic dynamic problem that has been traditionally solved using the stochastic dual dynamic programming (SDDP) approach. This LT schedule of releases should be met through short-term (ST) scheduling decisions obtained from a hydro-thermal scheduling that considers uncertainties. Both time scales can be linked if the ST problem considers as input the future cost function (FCF) obtained from LT studies. Known the piecewise-linear FCF, the hydro-scheduling can be solved as a one-stage problem. Under certain considerations a single segment of the FCF can be used to solve the schedule. From this formulation an equivalent model for the hydropower plant can be derived and used in ST studies. This model behaves accordingly to LT conditions to be met, and provides a marginal cost for dispatching the plant. A generation company (GENCO) owning a mix of hydro, wind, and thermal power will be the subject of study where the model will be implemented. The GENCO faces the problem of scheduling the hydraulic resource under uncertainties from e.g. wind and load while determining the market bids that maximize its profit under uncertainties from market prices. A two-stage stochastic unit commitment (SUC) for the ST scheduling implementing the equivalent hydro model will be solved.

  • 2.
    Bagheri, Azam
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Gu, Irene Y.H.
    Chalmers University of Technology.
    Improved characterization of multi-stage voltage dips based on the space phasor model2018Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 154, s. 319-328Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper proposes a method for characterizing voltage dips based on the space phasor model of the three phase-to-neutral voltages, instead of the individual voltages. This has several advantages. Using a K-means clustering algorithm, a multi-stage dip is separated into its individual event segments directly instead of first detecting the transition segments. The logistic regression algorithm fits the best single-segment characteristics to every individual segment, instead of extreme values being used for this, as in earlier methods. The method is validated by applying it to synthetic and measured dips. It can be generalized for application to both single- and multi-stage dips.

  • 3.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Yang, Kai
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Interharmonic currents from a Type-IV wind energy conversion system2017Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 143, s. 357-364Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents, for the first time, the verification of the classic model for the origin of interharmonic emission from a frequency converter, for a Type-IV wind turbine by using long-term measurements. Interharmonic variations in magnitude and in frequency are due to the difference between the generator-side and grid-side frequency of the full-power converter. The model verification consists of three parts: correlation between frequencies; relation between magnitude of interharmonics and active-power production, and relation between magnitudes of different interharmonics. The measurements are in agreement with the model predictions. The paper also introduces a novel graphical correlation method to extract information on interharmonics from long-term measurement series.

  • 4.
    Bracale, Antonio
    et al.
    Department for Technologies, University of Naples Parthenope.
    Carpinelli, Guido
    Department of Electrical Engineering, University of Naples Federico II.
    Gu, Irene
    Chalmers University of Technology, Department of Signals and Systems.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    A new joint sliding-window ESPRIT and DFT scheme for waveform distortion assessment in power systems2012Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 88, nr 7, s. 112-120Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper proposes a novel scheme that jointly employs a sliding-window ESPRIT and DFT for estimating harmonic and interharmonic components in power system disturbance data. In the proposed scheme, separate stages are utilized to estimate the voltage fundamental component, harmonics and interharmonics. This includes the estimation of the fundamental component from lowpass filtered data using a sliding-window ESPRIT, of harmonics from a sliding-window DFT with a synchronized window, and of interharmonics from the residuals by applying the sliding-window ESPRIT. Main advantages of the approach include high resolution and accuracy in parameter estimation and significantly reduced computational cost. Experiments and comparisons are made on both synthetic and measurement data. Results have shown the effectiveness and efficiency of the proposed scheme.

  • 5.
    Ehnberg, S.G. Jimmy
    et al.
    Chalmers University of Technology.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Reliability of a small power system using solar power and hydro2005Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 74, nr 1, s. 119-127Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper studies the availability of the electricity supply when the sources consist of a combination of solar energy and a small hydro installation. Instead of flow-of-river, a small reservoir is used. By not using the hydro energy during sunny periods, the natural flow-of-river fills up the reservoir for later use. A model for global solar radiation is proposed with an astronomical part (deterministic) and a meteorological part (stochastic). The meteorological part is based on a Markov model of the cloud coverage. The solar model does not require solar radiation measurements, just cloud observations. A case study has been performed for Timbuktu (16.75°N, 0.07°W) in which generation availability is simulated for four different cases: solar power only; solar power with storage; solar and hydro power and solar and hydro power with storage. To be able to use exclusively renewable energy sources, a combination of sources is needed to secure the reliability of the supply. Using solar cells in combination with a small reservoir is favorable. Even with a weak flow the affect of the flow on the day time reliability is minor, but great benefits can be found for reliability during low load hours (night time).

  • 6.
    Etherden, Nicholas
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Overload and overvoltage in low-voltage and medium-voltage networks due to renewable energy: some illustrative case studies2014Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 114, s. 39-48Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents the use of curtailment to allow more wind or solar power to be connected to a distribution network when overcurrent or overvoltage set a limit. Four case studies, all based on measurements, are presented. In all cases the hosting capacity method is used to quantify the gain in produced energy for increased levels of distributed renewable energy resources. A distinction is made between “hard curtailment” where all production is disconnected when overcurrent and overvoltage limits are exceeded and “soft curtailment” where the amount of production to be disconnected is minimized. It is shown that the type of curtailment method used has a large impact on the amount of delivered energy to the grid. The paper further discusses details of the curtailment algorithm, alternatives to curtailment, the communication needs and risks associated with the use of curtailment

  • 7.
    Ferreira, Danton D.
    et al.
    Federal University of Lavras.
    Seixas, Jose M. de
    Federal University of Rio de Janeiro, COPPE/Poli.
    Cerqueira, Augusto S.
    Department of Electrical Circuits, Federal University of Juiz de Fora, Campus Universitário.
    Duque, Carlos A.
    Department of Electrical Circuits, Federal University of Juiz de Fora, Campus Universitário.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Ribeiro, Paulo F.
    Federal University of Itajubá.
    A new power quality deviation index based on principal curves2015Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 125, s. 8-14, artikkel-id 4289Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, a new power quality deviation index based on principal curves is proposed. The index provides a quantitative measure, which gives an idea of how much the monitored electrical signal has deviated from the nominal one. Differently of existing indices, the proposed index is a general index, i.e., it can be used for any type of disturbance in the monitored signal. In addition, the proposed index is used to perform a direct approach for detecting disturbances in power signals. This approach is able to detect the beginning and localize the disturbance by analyzing non-overlapping signal windows of one cycle of the fundamental component, leading to a simple method in terms of computational complexity

  • 8. Filho, L.M.C
    et al.
    Leborgne, R.C
    Silveira, P.M da
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Voltage sag index calculation: comparison between time-domain simulation and short-circuit calculation2008Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 78, nr 4, s. 676-682Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper describes a case study where voltage sags indices are estimated using Monte Carlo approach combined with ATP (Alternative Transient Program) and short-circuit calculation program. Voltage sag magnitude and frequency are used to evaluate the correlation between both programs. The results indicate that time-domain simulation and short-circuit calculation gives similar voltage sag indices. Considering the high correlation between the results, short-circuit calculation programs are preferable over the time-domain simulation tools as the modelling for time-domain simulation is more complex, time consuming, and rarely covers the whole network.

  • 9.
    Gil de Castro, Aurora
    et al.
    Electronics Technology, 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.
    Light intensity variation (flicker) and harmonic emission related to LED lamps2017Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 146, s. 107-114Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper discusses two power-quality aspects of LED lamps: harmonics and flicker. Measurements have been performed of 24 different LED lamps: the harmonic current spectrum and light intensity variations have been measured. To enable an objective comparison, the light intensity variations were measured for all the lamps when exposed to the same voltage magnitude variations. Results show a large variety in harmonic emission between different LED lamps indicating that different technologies or different components are being used within the LED lamps. Moreover the results show a large variety in light intensity variations when different LED lamps are subjected to the same voltage fluctuations. A clear correlation was found between harmonic emission and sensitivity to voltage magnitude variations. Lamps with low light intensity variations are also the ones with the highest harmonic current emission. No clear relation between active power or price and sensitivity to voltage magnitude variations was found.

  • 10.
    Jesus, P. M. De Oliveira-De
    et al.
    Energy Institute and Department of Conversion and Energy Delivery, Simon Bolivar University, Caracas.
    Alvarez, Manuel
    Energy Institute and Department of Conversion and Energy Delivery, Simon Bolivar University, Caracas.
    Yusta, J. M.
    Department of Electrical Engineering, University of Zaragoza.
    Distribution power flow method based on a real quasi-symmetric matrix2013Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 95, s. 148-159Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a new load flow formulation to solve active and passive electric distribution networks. The fundamental idea discussed here is how to obtain the power flow solution by using the elements of a unique quasi-symmetric matrix called TRX in the iterative process. The method is formulated for single-phase balanced and three-phase unbalanced radially operated networks. It works with real variables as opposed to complex variables used in previous backward/forward sweep algorithms discussed in literature. The proposed TRX matrix constitutes a complete database by including information of network topology structure as well as branch impedances of the distribution feeder. Data arrangement is suitable to be exchanged under standard Common Information Model (CIM) under Distribution Management Systems (DMS) environment allowing an efficient computation of the state of the system for on-line and off-line study applications. The proposed methodology was applied on a group of IEEE test systems and a real distribution system of 49,000 nodes. © 2012 Elsevier B.V. All rights reserved.

  • 11.
    Leborgne, Roberto Chouhy
    et al.
    Federal University of Rio Grande do Sul (UFRGS), Porto Alegre.
    Oliveira, Thiago Clé de
    Itajuba Federal University, Brazil.
    Filho, José Maria de Carvalho
    Itajuba Federal University, Brazil.
    Oliveira, Jeder Francisco de
    CEMIG, Belo Horizonte.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    New approach for power lines performance estimation based on load variation due to voltage sags2011Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 83, nr 1, s. 35-40Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The power line performance has traditionally been assessed in terms of its efficiency and reliability. The increase of the effect of voltage sags on sensitive loads, maybe located far away from the faulted line, is the reason to carry out a new analysis of power line's performance. A new method to evaluate the power line performance, based on voltage sag indices, is proposed. The voltage sag indices suggested to assess power lines performance are the load variation, the non delivered energy and the total cost due to voltage sags. The proposed power line performance is compared with the traditional performance based on power line outages. The results show that the proposed method can change the assessment of power lines performance and therefore the utility focus for investment.

  • 12.
    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 dips2010Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 80, nr 12, s. 1452-1458Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 13.
    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 monitors2017Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 146, s. 63-70Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 14.
    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 challenges2017Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 150, s. 1-10Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 15.
    Sakar, Selcuk
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Balci, Murat E.
    Electrical and Electronics Engineering, Balikesir University.
    Abdel Aleem, Shady H.E.
    15th of May Higher Institute of Engineering, Mathematical and Physical Sciences, Helwan, Cairo.
    Zobaa, Ahmed F.
    College of Engineering, Design & Physical Sciences, Brunel University London.
    Increasing PV hosting capacity in distorted distribution systems using passive harmonic filtering2017Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 148, s. 74-86Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Adding new capacity expansion alternatives using distributed generation (DG) technologies, particularly penetration of renewable energy, has several economical, and technical advantages such as the reduced system costs, the improved voltage profile, lower line loss and enhanced system’s reliability. However, the DG units may lead to power quality, energy efficiency, and protection problems in the system when their penetration exceeds a particular value, generally called as the system’s hosting capacity (HC) in the literature. In this paper, the HC determination of a distorted distribution system with Photovoltaic (PV)-based DG units is handled as an optimization problem by considering over and under voltage limitations of buses, current carrying capabilities of the lines, and harmonic distortion limitations as constraints. It is seen from simulation results that the HC is dramatically decreased with the increment of the load’s nonlinearity level and the utility side’s background voltage distortion. Accordingly, a C-type passive filter is designed to maximize the harmonic-constrained HC of the studied system while satisfying the constraints. The results indicate that higher HC level can be achieved using the proposed filter design approach compared to three conventional filter design approaches as voltage total harmonic distortion minimization, line loss minimization and power factor maximization.

  • 16.
    Santos, Ivan Nunes
    et al.
    Federal University of Uberlândia.
    Ćuk, Vladimir
    Eindhoven University of Technology.
    Almeida, Pedro M.
    Federal University of Juiz de Fora, Minas Gerais.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Ribeiro, Paulo Fernando
    Federal University of Itajubá, Universidade Federal de Pernambuco, Recife, Calvin College, Grand Rapids, MI.
    Considerations on hosting capacity for harmonic distortions on transmission and distribution systems2015Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 119, s. 199-206Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The increasing penetration of renewable/distributed sources with non-linear characteristics demands a clear methodology for determining the amount of generation which can be connected to the system without deteriorating the performance (the hosting capacity). This paper proposes a methodology for determining the hosting capacity regarding harmonic distortions. The method includes aggregation effects of harmonic currents, the influence of harmonic distortion limits and harmonic generation profile. To exemplify an application of the proposed procedure, a simple case study is performed and analyzed.

  • 17.
    Wang, Ying
    et al.
    College of Electrical Engineering and Information Technology, Sichuan University.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bagheri, Azam
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Xiao, Xian-Xong
    College of Electrical Engineering and Information Technology, Sichuan University.
    Olofsson, Magnus
    Elforsk, Energiforsk AB, Stockholm.
    A quantitative comparison approach for different voltage dip characterization methods2016Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 133, s. 182-190Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a systematic approach to compare different methods for characterizing voltage dips in a quantitative way. A prediction error is calculated between measured and synthetic dips (reproduced from single-event characteristics for the measured dips) with respect to the way they impact the performance of a generic device. The proposed approach is illustrated by comparing seven different characterization methods and their ability to predict the minimum dc-bus voltage of a three-phase adjustable-speed drive. A generic model of such a drive is used for this. Based in this comparison it is concluded that characterization method for dips in three-phase systems should include unbalance and phase-angle jump.

  • 18. Yang, Kai
    et al.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Amaris, Hortensia
    University Carlos III, Madrid.
    Alvarez, Carlos
    Energy to Quality, Madrid.
    Decompositions of harmonic propagation in wind power plant2016Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 141, s. 84-90Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents harmonic propagation in a wind power plant. The two groups of propagation are distinguished based on the harmonic sources: propagation from one individual wind turbine to other turbines and to the public grid; and propagation from the public grid to the collection grid and to individual wind turbines. The paper studies the characteristics of the different harmonic propagation paths. A case with emission from all turbines, at different production levels, and from the public grid is presented as well. Also the impact of a turbine filter on the propagation is studied. The study indicates that, resonances of a wind power plant have a significant impact on the propagation. It is also shown that harmonic studies should consider both emission originating from turbines and emission originating from the public grid. It is also shown that the filter with the turbine has a significant impact on the harmonic propagation.

  • 19.
    Yang, Kai
    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.
    Measurements of harmonic emission versus active power from wind turbines2014Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, nr 108, s. 304-314Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents harmonic measurements from three individual wind turbines (2 and 2.5MW size). Both harmonics and interharmonics have been evaluated, especially with reference to variations in the active-power production. The overall spectra reveal that, emission components may occur at any frequency and not only at odd harmonics. Interharmonics and even harmonics emitted from wind turbines are relatively high. Individual frequency components depend on the power production in dierent ways: characteristic harmonics are independent of power; interharmonics show a strong correlation with power; other harmonic and interharmonic components present various patterns. It is concluded that the power production is not the only factor determining the current emission of a wind energy conversion system.

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