Change search
Refine search result
1 - 32 of 32
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Axelsson, Urban
    et al.
    Vattenfall Research & Development.
    Holm, Anders
    Vattenfall Research & Development.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Yang, Kai
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Propagation of harmonic emission from the turbines through the collection grid to the public grid2013In: 22nd International Conference and Exhibition on Electricity Distribution (CIRED 2013): Stockholm, Sweden, 10 - 13 June 2013, Red Hook, NY: Curran Associates, Inc., 2013, article id 650Conference paper (Refereed)
    Abstract [en]

    This paper addressed the harmonic emission from a large off-shore wind farm. An overview is given of the issues, where a distinction is made between frequencies below and above 2 kHz. Three different approaches are presented: a simplified mathematical model; a more detailed mathematical model; and measurements at the point of connection for an off-shore wind farm. It is concluded from both models and measurements that the emission is small for frequencies above a few kHz. However, specific resonances at higher frequencies involving the power transformers, when coinciding with switching frequencies or harmonics of switching frequencies, could result in high emission even at these high frequencies. Studies, including the propagation through the collection grid, are needed with the connection of any wind park to the grid.

  • 2.
    Axelsson, Urban
    et al.
    Vattenfall Research & Development.
    Holm, Anders
    Vattenfall Research & Development.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Yang, Kai
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Propagation of harmonic emission from the turbines through the collection grid to the public grid2012Conference paper (Refereed)
    Abstract [en]

    This paper addresses the harmonic emission from a large off-shore wind farm. An overview is given of the issues, where a distinction is made between frequencies below and above 2 kHz. Three different approaches are presented: a simplified mathematical model; a more detailed mathematical model; and measurements and the point of connection for an off-shore wind farm. It is concluded from both models and measurements that the emission is small for frequencies above a few kHz. However, specific resonances at higher frequencies involving the power transformers, when coinciding with switching frequencies or harmonics of switching frequencies, could result in high emission even at these high frequencies.

  • 3.
    Bollen, Math
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Cundeva, S
    Etherden, Nicholas
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Yang, Kai
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Considering the needs of the customer in the electricity network of the future2012Conference paper (Refereed)
    Abstract [en]

    The main purpose of the electric power system and the electricity network (power grid) is to supply electrical energy to the consumers. The interest of those consumers is in the price of electricity and in the performance of the delivery of the electrical energy. For the electricity producers, the aim of the grid is to enable the transport of electricity from them to the consumers. Also for the producers the importance is in costs and performance. Performance of the grid is typically divided into two parts: continuity of supply and voltage quality.The appearance of the smart grid, introduced as the use of new technology, methodology or market principles, to address new challenges, impacts continuity of supply and voltage quality. Such challenges include new types of production, new types of consumption, and electricity markets, but also increasing demands by customers on continuity of supply and voltage quality.This paper discusses a number of examples of new thinking for addressing the challenges that the power system has to cope with.An alternative approach for overload protection of subtransmission grids will be proposed, where the “smartness” is in the fact that the overload protection does not remove the overloaded component but the cause of the overload. Upon detection of an overload, the protection disconnects part or whole of curtailable customers to reduce the current through the lines to a level below the overload limit. As a result subtransmission lines can be operated without any reserve, so that more customers can be connected for the same costs while at the same time the continuity of supply for the non-curtailable customers is not impacted.The limits set to the hosting capacity by the risk of overvoltages due to distributed generation can be removed either by new technology (curtailment of production) or by allowing occasional overvoltages. An example will be provided to show the probability of an overvoltage occurring with a low-voltage customer when increasing amounts of wind power are connected to a medium-voltage feeder.An example of the measured emission from wind turbines will be presented. Allowing higher levels of non-characteristic harmonics is a possible alternative for strict emission limits on new installations.The provided examples of the use of new technology and/or new ways of thinking are part of the transition to the smart grid. Such new thinking in combination with new technology will be an important element in the transition to the future electricity network i.e. the “smart grid”. With any design or operation issue of the power system it remains important to always keep the main aims of the power system in mind: to maintain acceptable continuity of supply and voltage quality for all network users at a reasonable price.

  • 4.
    Bollen, Math
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Cundeva, S.
    University Sts. Cyrill and Methodias, Skopje.
    Rönnberg, Sarah
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wahlberg, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Yang, Kai
    Yao, L
    Areva T and D, Technology Centre, Stafford.
    A wind park emitting characteristic and non-characteristic harmonics2010In: 2010 14th International Power Electronics and Motion Control Conference (EPE/PEMC 2010): Ohrid, Macedonia, 6 - 8 September 2010, Piscataway, NJ: IEEE Communications Society, 2010, p. S14-22-S14-26Conference paper (Refereed)
    Abstract [en]

    This paper shows measurements of the emission of harmonics by a small windpark. The spectrum consists of the characteristic harmonics associated with six-pulse converters and a broadband spectrum covering frequencies at which emission normally is not present. These frequencies are caused by the switching pattern of the power-electronics converters. Similar spectra have been reported by other authors and for other types of modern converters. Whereas the actual emission is small, the presence of emission at non-characteristic frequencies could result in voltage distortion limits being exceeded.

  • 5.
    Bollen, Math
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Etherden, Nicholas
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Yang, Kai
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Chang, G. W
    National Chung Cheng University.
    Continuity of supply and voltage quality in the electricity network of the future2012In: 15th International Conference on Harmonics and Quality of Power (ICHQP), IEEE Communications Society, 2012, p. 375-377Conference paper (Refereed)
    Abstract [en]

    This paper introduces three examples of new thinking for addressing the challenges that the power system has to cope with. Such new thinking in combination with new technology will be an important element in the transition to the future electricity network (the —). With overload protection it is important to not remove the overloaded component but the cause of the overload so as to protect the other network users against an interruption. The limits set to the hosting capacity by potential overvoltages can be removed either by new technology (curtailment of production) or by allowing occasional overvoltages. Allowing higher levels of non-characteristic harmonics is a possible alternative for strict emission limits on new installations. In all cases it is essential that the interests of the network user are considered.

  • 6.
    Bollen, Math
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Meyer, Jan
    Dresden University of Technology.
    Amaris, Hortensia
    University Carlos III, Madrid.
    Blanco, Ana María
    Technical University Dresden.
    Gil-de-Castro, Aurora
    University of Cordoba.
    Desmet, Jan
    Ghent University.
    Klatt, Mattias
    Technical University Dresden.
    Kocewiak, Lukasz
    DONG Energy Wind Power, Fredericia.
    Rönnberg, Sarah
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Yang, Kai
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Future work on harmonics: some expert opinions part I – wind and solar power2014Article in journal (Refereed)
    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. The results of this discussion are summarized in this paper and some of the issues are discussed in more detail in this paper and in its companion paper. This paper discusses emission from wind and solar power as well as advantages and disadvantages of active and passive filters.

  • 7.
    Bollen, Math
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Yang, Kai
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Harmonic aspects of wind power integration2013In: Journal of Modern Power Systems and Clean Energy, ISSN 2196-5625, E-ISSN 2196-5420, Vol. 1, no 1, p. 14-21Article in journal (Other academic)
    Abstract [en]

    This paper discusses a number of ways in which wind power installations can impact the harmonic levels in the power system. Wind turbines are an additional source of harmonic emission, especially when it concerns “non-characteristic harmonics.” Parallel resonances can amplify the emission from individual turbines. A mathematical model is developed to quantify this amplification. Series resonances can result in high currents, driven by the background voltage distortion in the transmission grid, flowing into the wind park. Weakening of the transmission grid will increase lower order harmonics but reduce higher order harmonics.

  • 8.
    Bollen, Math
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Yang, Kai
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Harmonics – another aspect of the interaction between wind-power installations and the grid2013In: 22nd International Conference and Exhibition on Electricity Distribution (CIRED 2013): Stockholm, Sweden, 10 - 13 June 2013, Red Hook, NY: Curran Associates, Inc., 2013, article id 408Conference paper (Refereed)
    Abstract [en]

    Wind parks are known as sources of harmonic distortion. The emission at the classical harmonic frequencies (low order non-triplen odd harmonics) is however low. Potential problems with connecting individual turbines and wind parks occur at non-standard frequencies, mainly due to harmonic resonances. Next to the harmonic currents driven by the emission from the turbines, studies should also consider the currents driven by the harmonic background distortion.

  • 9.
    Bollen, Math
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Yang, Kai
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Interharmonic currents from a Type-IV wind energy conversion system2017In: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 143, p. 357-364Article in journal (Refereed)
    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.

  • 10. Cundeva, Snezana
    et al.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Yang, Kai
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Distortion levels in the grid due to windpower integration2013Conference paper (Other academic)
  • 11.
    Meyer, Jan
    et al.
    Technical University Dresden.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    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 University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Yang, Kai
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Future work on harmonics: some expert opinions part II – supraharmonics, standards and measurements2014Article in journal (Refereed)
    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

  • 12.
    Rönnberg, Sarah
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Yang, Kai
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Gil-de-Castro, Aurora
    Waveform distortion: a comparison of photovoltaic and wind power2014Article in journal (Refereed)
    Abstract [en]

    The paper presents measurements of waveform distortion from six solar-power installations and three wind-power installations. The main emphasis is on the emission of low-order odd harmonics as a function of active-power production. It is concluded that the emission levels are low, that there is in most cases just a weak correlation with active power production, and that every installation is unique. Next to that the paper contains a discussion on the emission of supraharmonics (mainly 16 kHz in the case shown). Both for low-order harmonics and for supraharmonics, there is a need for the development of suitable models explaining the emission, including any relation with active-power production

  • 13.
    Yang, Kai
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    On Harmonic Emission, Propagation and Aggregation in Wind Power Plants2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The increasing use of wind energy is a global trend as part of the overall transition to a more sustainable energy system. By using modern technologies, the wind energy is converted into electric power which is transported to the consumers by means of the electric power system. The use of these technologies, in the meantime, plays a significant role in maintaining power quality in the electric power system; including positive as well as negative impacts. This thesis emphasises on harmonic distortion within a wind power plant (WPP), for a wind turbine and for the plant level.The harmonic study presented in this thesis has been based on field measurements at a few different individual wind turbines and at a second location in one WPP. In general, the levels of harmonic distortion as percentage of the turbine and WPP ratings are low. Among the frequency components, even harmonics and especially interharmonics are present at levels comparable with the levels of characteristic harmonics. The measurements show that both harmonics and interharmonics vary strongly with time. Interharmonics further show a strong dependence on the active power production of the turbine, while characteristic harmonics are independent on the power production. The even harmonics and interharmonics may excite any resonance in the collection grid or in the external grid.The origin of interharmonic emission due to power converters has been verified through a series of measurements over a two-week period. The interharmonic emission originates from the difference between the generator-side frequency and the power system frequency. A series of interharmonic frequencies are produced and they vary in accordance with the generator-side frequency. Both these interharmonic frequencies and the magnitudes are related to each other, and the theoretical relations have been confirmed through the measurements.The harmonic propagation in a collection grid has been studied by using transfer functions. Without the need to know the harmonic sources, the characteristics of harmonic propagations are quantified through transfer functions. The method has been used to estimate the total harmonic level in a WPP, by combining knowledge of the transfer function with information from harmonic emission of the individual wind turbines. The harmonic aggregation of the emission from the individual turbines towards the point of connection (PoC) has been studied as well. From the studies it was found that interharmonics show a stronger cancellation compared to harmonics, especially compared to lower-order harmonics.According to the object of interest and the harmonic propagation, a distinction has been made between primary and secondary emission. A more detailed classification of the different propagations within a WPP has been proposed. A systematic approach for harmonic studies in association with WPPs has resulted from this. The harmonic voltages and currents at any location are obtained as the superposition of the contribution from different emission sources to this specific location. This location can be either within the WPP or in the external grid. The studies presented conclude that all the contributions should be included to get a reasonable overview of the harmonic distortion in the WPP.

  • 14.
    Yang, Kai
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wind-turbine harmonic emissions and propagation through a wind farm2012Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The increasing demand for sustainable energy is one of the driving forces behind the increasing use of wind power by means of wind-turbines in electric power systems. Modern wind turbines commonly employ variable-speed-generator technology associated with a power-electronic converter as part of the grid connection. A drawback of the use of power electronics is the presence of harmonic emissions. Consequently a systematic study on distortion from wind power installations is needed; this holds for individual wind turbines as well for complete installations.In the work, measurements and analysis of harmonic emissions were performed on a number of wind-turbines in several wind parks in Northern Sweden. The measurements on the individual wind turbines reveal that the harmonic emissions are different from each other, even for different turbines from the same manufacturer. However in general the characteristic harmonics dominate the harmonic emissions. Furthermore, a long-term measurement shows that the dominant frequencies in the emission change with time.The total emission from a wind park into the public grid is determined by the emission from individual turbines and by the properties of the wind park. To study the impact of the wind park on the propagation a ``transfer function'' method has been introduced, and applied by means of calculation and simulation. The method is based on a mathematical model that predicts the harmonic propagation from the wind turbines to the public grid in the frequency range up to 50 kHz. Applying the model to three example parks reveals that, the amplitudes at the resonance frequency are strongly dependent on the resistance of both underground cables and transformer, especially at high frequencies. In other words, the higher order harmonics are damped a lot.In conclusion, wind park harmonic emissions into the public grid are due to the combination of emission from individual wind turbines and the propagation through the collection grid.

  • 15.
    Yang, Kai
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Measurements of Complex Harmonic Current on Two Wind turbines2014In: The Renewable Energies and Power Quality Journal (RE&PQJ), ISSN 2172-038X, E-ISSN 2172-038X, no 12, article id 297Article in journal (Refereed)
  • 16. Yang, Kai
    et al.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Amaris, Hortensia
    University Carlos III, Madrid.
    Alvarez, Carlos
    Energy to Quality, Madrid.
    Decompositions of harmonic propagation in wind power plant2016In: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 141, p. 84-90Article in journal (Refereed)
    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.

  • 17.
    Yang, Kai
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Larsson, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Aggregation and amplification of wind-turbine harmonic emission in a wind park2015In: 2015 IEEE Power & Energy Society General Meeting: 26-30 July 2015, Denver CO, Piscataway, NJ: IEEE Communications Society, 2015Conference paper (Other academic)
    Abstract [en]

    This paper presents measurements of harmonic and interharmonic current (with 5 Hz frequency resolution) in the complex plane. The complex currents are spread around a center point. For interharmonics this center corresponds with the origin of the complex plane. For integer harmonics this center is off-set from the origin. A goodness-of-fit test reveals that phase angles of most interharmonics are uniformly distributed. A Monte-Carlo simulation based on the measurements has been performed to study the aggregation of the emission from individual turbines to the public grid. Low-order integer harmonics show less cancellation compared to high-order harmonics. Interharmonics aggregate close to the square-root rule for uniform phase angles.

  • 18.
    Yang, Kai
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Larsson, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Aggregation and Amplification of Wind-Turbine Harmonic Emission in a Wind Park2015In: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 30, no 2, p. 791-799, article id 7042349Article in journal (Refereed)
    Abstract [en]

    This paper presents measurements of harmonic and interharmonic current (with 5 Hz frequency resolution) in the complex plane. The complex currents are spread around a center point. For interharmonics this center corresponds with the origin of the complex plane. For integer harmonics this center is off-set from the origin. A goodness-of-fit test reveals that phase angles of most interharmonics are uniformly distributed. A Monte-Carlo simulation based on the measurements has been performed to study the aggregation of the emission from individual turbines to the public grid. Low-order integer harmonics show less cancellation compared to high-order harmonics. Interharmonics aggregate close to the square-root rule for uniform phase angles.

  • 19.
    Yang, Kai
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Larsson, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wind power harmonic aggregation of multiple turbines in power bins2014In: International Conference on Harmonics and Quality of Power. Proceedings: , p. 723-727, article id 6842922Article in journal (Refereed)
    Abstract [en]

    The paper presents current harmonic and interharmonic measurement of a Type-IV wind turbine. Characterizations and classifications have been performed with the representation of harmonics and interharmonics in a complex plane. The study of aggregations due to the summation of complex currents has been performed based on Monte-Carlo Simulation for harmonics and interharmonics. Aggregations occur less for low-order harmonics, more for high-order harmonics and most for interharmonics. Aggregations are shown to be largely independent of the produced power

  • 20.
    Yang, Kai
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Larsson, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wahlberg, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    A statistic study of harmonics and interharmonics at a modern wind-turbine2014In: International Conference on Harmonics and Quality of Power. Proceedings: , p. 718-722, article id 6842921Article in journal (Refereed)
    Abstract [en]

    The work presents measurements of harmonics and interharmonics from a modern wind turbine over a period of several days, using a conventional power quality monitor. A statistical study has been performed to present the characteristics of the emission during the measurement. A variation of emission has been observed, especially for interharmonics within certain low-frequency bands and for the switching frequency. Multiple relations between voltage and current components have been presented, as well as multiple relations between the emission and the active-power production. Generally, harmonics are independent of the active-power, whereas interharmonics are dependent on it.

  • 21.
    Yang, Kai
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Larsson, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wahlberg, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Measurements of harmonic emission versus active power from wind turbines2014In: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, no 108, p. 304-314Article in journal (Refereed)
    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.

  • 22.
    Yang, Kai
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wahlberg, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    A comparison study of harmonic emission measurements in four windparks2011In: 2011 IEEE Power and Energy Society General Meeting, Piscataway, NJ: IEEE Communications Society, 2011Conference paper (Refereed)
    Abstract [en]

    This paper presents measurements of harmonic current emissions up till 2 kHz from four different windparks in northern Sweden, all equipped with modern power-electronics converters. The measurement results are presented in different ways, including a method to quantify the impact on the grid and a method to show the variations in the spectrum with time. The results show that there exists different dominating harmonics in different windturbines and that the magnitudes of the individual frequency components vary strongly with time. Each turbine however shows a broadband component with superimposed narrowband components. The impact on the grid, with reference to permissible levels of voltage distortion, is biggest for the interharmonic components

  • 23.
    Yang, Kai
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wahlberg, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Characteristic and non-characteristic harmonics from windparks2011In: Proceedings of CIRED 21st International Conference on Electricity Distribution, CIRED - Congrès International des Réseaux Electriques de Distribution, 2011, article id 0251Conference paper (Refereed)
    Abstract [en]

    This paper presents measurements of harmonic current emissions up till 2 kHz from four different windparks in northern Sweden, all equipped with modern power-electronics converters. A study of the four windparks was performed interms of 95% value of harmonic current spectrum and the minimum fault-level needed to fulfil the EN 50160 requirements on voltage distortion. The results show that there exists different dominating harmonics and fault-level requirements for different windturbines. Each turbine however shows a broadband component with superimposed narrowband components. The impact on the grid, with reference to permissible levels of voltage distortion, is biggest for the interharmonic components.

  • 24.
    Yang, Kai
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wahlberg, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Comparison of harmonic emissions at two nodes in a windpark2012In: 15th IEEE International Conference on Harmonics and Quality of Power (ICHQP 2012), IEEE Communications Society, 2012, p. 313-319Conference paper (Refereed)
    Abstract [en]

    This work presents a comparison study of measurements of power quality, with emphasis on voltage and current distortion, at two locations in the same windpark, located in northern Sweden. Emissions at both locations are compared based on both harmonics and interharmonics. A complete picture of spectrum during the measurement is presented to show the variations of emission in the windpark. Some dominating harmonics are further analyzed.

  • 25.
    Yang, Kai
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wahlberg, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Measurements at two different nodes of a windpark2012In: 2012 IEEE Power and Energy Society General Meeting, Piscataway, NJ: IEEE Communications Society, 2012Conference paper (Refereed)
    Abstract [en]

    This paper presents measurements of power quality, with emphasis on voltage and current distortion, simultaneously at two locations in the same windpark, located in northern Sweden. Both harmonics and interharmonics components are considered in the study. Similarities and differences between voltage and current distortion are presented in this paper and possible explanations are discussed. One of the conclusions is that there is no simple relation between voltage and current distortion in a windpark.

  • 26.
    Yang, Kai
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wahlberg, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Measurements of four-windpark harmonic emissions in northern Sweden2012Conference paper (Refereed)
    Abstract [en]

    This paper presents measurements of harmonic current emissions up till few kHz from four different wind parks in northern Sweden, all equipped with modern power-electronics converters. Measurements have been performed with 10-minute time resolution between one and several weeks. The measurement results are presented in different ways, including a method to show the variations in the harmonic emissions with time. The results show that there exists different dominating harmonics in different wind turbines and that the magnitudes of the individual frequency components vary strongly with time. Each turbine however shows a broadband component with superimposed narrowband components.

  • 27.
    Yang, Kai
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wahlberg, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wind power harmonic emission versus active-power production2014Conference paper (Refereed)
  • 28.
    Yang, Kai
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Yao, Liangzhong
    Alstom Transport Information Solution.
    Theoretical emission study of windpark grids: Emission propagation between windpark and grid2011In: Proceeding of the International Conference on Electrical Power Quality and Utilisation, EPQU, Piscataway, NJ: IEEE Communications Society, 2011, p. 559-564Conference paper (Refereed)
    Abstract [en]

    This paper presents the results from a theoretical study on the harmonic emission of a windpark in the frequency range up to 200 kHz. The calculations are based on the transfer function from an individual turbine to the pubic grid, expressed in the frequency domain. The model has been applied to a general windpark, for which a mathematical expression has been derived. The study provides relations between different parameters in the windpark and the transfer functions. An important conclusion from the study is that emission into the public grid is negligible for frequencies above a few kHz.

  • 29.
    Yang, Kai
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Cundeva, S
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wahlberg, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Harmonic emission study of individual wind turbines and a wind park2013In: The Renewable Energies and Power Quality Journal (RE&PQJ), ISSN 2172-038X, E-ISSN 2172-038X, no 11Article in journal (Refereed)
  • 30.
    Yang, Kai
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Cundeva, S.
    University Sts. Cyrill and Methodias, Skopje, Institute of Electroheat Faculty of Electrical Engineering and Information Technology.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wahlberg, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Measurements of harmonic and interharmonic emission from wind power systems2014In: Russian Electrical Engineering, ISSN 1068-3712, Vol. 85, no 12, p. 769-776Article in journal (Refereed)
    Abstract [en]

    With increasing amounts of wind power connected, the power system is impacted in a number of ways. In this paper, the emphasis is on one of those impacts: the harmonic and interharmonic emission from wind-power installations. The emission of individual wind turbines as well as from a wind park has been studied. The spectrum as a function of active-power has been studied. Various trends of emission according to the output power have been presented. For four modern wind turbines estimations have been done on the impact on the grid for each harmonic and interharmonic subgroup. The primary emission from a complete windpark due to the emission from the turbines has been analyzed

  • 31.
    Yang, Kai
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Cundeva, Snezana
    Institute of Electroheat Faculty of Electrical Engineering and Information Technology.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wahlberg, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Harmonic aspects of wind-power installations2013Conference paper (Refereed)
    Abstract [en]

    With increasing amounts of wind power connected, the power system is impacted in a number of ways. In this paper, the emphasis has been on one of those impacts: the harmonic emission from wind-power installations. The harmonic emission of individual wind turbines as well as from a wind park has been studied. For four modern wind turbines estimations have been done on the impact on the grid per harmonic and interharmonic group. The primary emission from complete windpark due to the emission from the turbines has been analyzed.

  • 32.
    Yang, Kai
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Schwanz, Daphne
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Harmonic aggregation and amplification in a wind-park2015Conference paper (Refereed)
    Abstract [en]

    This paper studies the harmonic emission in a wind park,using a current transfer function. The emission of anindividual wind turbine has been measured during aperiod of a few weeks covering all output productions.The wind park harmonic emission is analyzed by theaverage spectrum at the collection point. The amount ofemission of the wind park as a whole is modeled by astochastic method, based on the Monte-Carlo Simulation.The measured harmonics at wind turbines have beenanalyzed and compared with the simulated overallemission at the collection point of the wind park. Theresults will be showed by graphs and some discussionswill be made.

1 - 32 of 32
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf