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Yang, Kai
Publications (10 of 32) Show all publications
Bollen, M. & Yang, K. (2017). Interharmonic currents from a Type-IV wind energy conversion system. Electric power systems research, 143, 357-364
Open this publication in new window or tab >>Interharmonic currents from a Type-IV wind energy conversion system
2017 (English)In: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 143, p. 357-364Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Elsevier, 2017
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electric Power Engineering
Identifiers
urn:nbn:se:ltu:diva-59994 (URN)10.1016/j.epsr.2016.09.010 (DOI)000390965300038 ()2-s2.0-84992694544 (Scopus ID)
Note

Validerad; 2016; Nivå 2; 2016-10-27 (andbra)

Available from: 2016-10-27 Created: 2016-10-27 Last updated: 2018-09-13Bibliographically approved
Yang, K., Bollen, M., Amaris, H. & Alvarez, C. (2016). Decompositions of harmonic propagation in wind power plant (ed.). Electric power systems research, 141, 84-90
Open this publication in new window or tab >>Decompositions of harmonic propagation in wind power plant
2016 (English)In: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 141, p. 84-90Article in journal (Refereed) Published
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.

National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electric Power Engineering
Identifiers
urn:nbn:se:ltu:diva-14930 (URN)10.1016/j.epsr.2016.06.029 (DOI)000385598200008 ()2-s2.0-84980329458 (Scopus ID)e5e1b5d2-2df1-4765-bffb-876236d011d6 (Local ID)e5e1b5d2-2df1-4765-bffb-876236d011d6 (Archive number)e5e1b5d2-2df1-4765-bffb-876236d011d6 (OAI)
Note

Validerad; 2016; Nivå 2; 20160815 (andbra)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Yang, K., Bollen, M. & Larsson, A. (2015). Aggregation and amplification of wind-turbine harmonic emission in a wind park (ed.). In: (Ed.), (Ed.), 2015 IEEE Power & Energy Society General Meeting: 26-30 July 2015, Denver CO. Paper presented at IEEE Power & Energy Society General Meeting : 26/07/2015 - 30/07/2015. Piscataway, NJ: IEEE Communications Society
Open this publication in new window or tab >>Aggregation and amplification of wind-turbine harmonic emission in a wind park
2015 (English)In: 2015 IEEE Power & Energy Society General Meeting: 26-30 July 2015, Denver CO, Piscataway, NJ: IEEE Communications Society, 2015Conference paper, Published 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.

Place, publisher, year, edition, pages
Piscataway, NJ: IEEE Communications Society, 2015
Series
IEEE Power and Energy Society General Meeting, ISSN 1944-9925
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electric Power Engineering
Identifiers
urn:nbn:se:ltu:diva-30136 (URN)10.1109/PESGM.2015.7285778 (DOI)3df3fa12-02b1-452a-9419-de470e6a633e (Local ID)3df3fa12-02b1-452a-9419-de470e6a633e (Archive number)3df3fa12-02b1-452a-9419-de470e6a633e (OAI)
Conference
IEEE Power & Energy Society General Meeting : 26/07/2015 - 30/07/2015
Note
Godkänd; 2015; 20151007 (andbra)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-06-14Bibliographically approved
Yang, K., Bollen, M. & Larsson, A. (2015). Aggregation and Amplification of Wind-Turbine Harmonic Emission in a Wind Park (ed.). Paper presented at . IEEE Transactions on Power Delivery, 30(2), 791-799, Article ID 7042349.
Open this publication in new window or tab >>Aggregation and Amplification of Wind-Turbine Harmonic Emission in a Wind Park
2015 (English)In: 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) Published
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.

Keywords
Wind power generation, Power quality, Power conversion harmonics, Harmonic analysis, Phase estimation, Technology - Electrical engineering, electronics and photonics, Teknikvetenskap - Elektroteknik, elektronik och fotonik
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electric Power Engineering
Identifiers
urn:nbn:se:ltu:diva-10632 (URN)10.1109/TPWRD.2014.2326692 (DOI)000351744400031 ()2-s2.0-85027931544 (Scopus ID)976f9d17-a120-4bb9-8379-aa5d05c879a6 (Local ID)976f9d17-a120-4bb9-8379-aa5d05c879a6 (Archive number)976f9d17-a120-4bb9-8379-aa5d05c879a6 (OAI)
Note
Validerad; 2015; Nivå 2; 20140831 (kaiyan)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Yang, K., Schwanz, D. & Bollen, M. (2015). Harmonic aggregation and amplification in a wind-park (ed.). Paper presented at International Conference and Exhibition on Electricity Distribution : 15/06/2015 - 18/06/2015. Paper presented at International Conference and Exhibition on Electricity Distribution : 15/06/2015 - 18/06/2015.
Open this publication in new window or tab >>Harmonic aggregation and amplification in a wind-park
2015 (English)Conference paper, Oral presentation only (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.

National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electric Power Engineering
Identifiers
urn:nbn:se:ltu:diva-32567 (URN)71aea5a0-31d2-40ee-9864-ab9bd6bd7723 (Local ID)71aea5a0-31d2-40ee-9864-ab9bd6bd7723 (Archive number)71aea5a0-31d2-40ee-9864-ab9bd6bd7723 (OAI)
Conference
International Conference and Exhibition on Electricity Distribution : 15/06/2015 - 18/06/2015
Note
Godkänd; 2015; 20150817 (matbol)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
Yang, K. (2015). On Harmonic Emission, Propagation and Aggregation in Wind Power Plants (ed.). (Doctoral dissertation). Paper presented at . Luleå tekniska universitet
Open this publication in new window or tab >>On Harmonic Emission, Propagation and Aggregation in Wind Power Plants
2015 (English)Doctoral 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.

Place, publisher, year, edition, pages
Luleå tekniska universitet, 2015. p. 184
Series
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electric Power Engineering
Identifiers
urn:nbn:se:ltu:diva-18678 (URN)9c8d5902-9d7c-4409-864b-532b0c6ba651 (Local ID)978-91-7583-260-9 (ISBN)978-91-7583-261-6 (ISBN)9c8d5902-9d7c-4409-864b-532b0c6ba651 (Archive number)9c8d5902-9d7c-4409-864b-532b0c6ba651 (OAI)
Note

Godkänd; 2015; 20150130 (kaiyan); Nedanstående person kommer att disputera för avläggande av teknologie doktorsexamen. Namn: Kai Yang Ämne: Elkraftteknik /Electric Power Engineering Avhandling: On Harmonic Emission, Propagation and Aggregation in Wind Power Plants. Opponent: Professor Roberto Langella, Scientific Responsible of the Second University of Naples local Research Section of EnSiEL, Naples, Italien. Ordförande: Professor Math Bollen, Avd för Energivetenskap, Institutionen för Teknikvetenskap och matematik, Luleå tekniska universitet, Skellefteå. Tid: Fredag 17 april kl 10.00 Plats: Hörsal A, Campus Skellefteå

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
Yang, K., Bollen, M., Larsson, A. & Wahlberg, M. (2014). A statistic study of harmonics and interharmonics at a modern wind-turbine (ed.). Paper presented at International Conference on Harmonics and Quality of Power : 25/05/2014 - 28/05/2014. , 718-722, Article ID 6842921.
Open this publication in new window or tab >>A statistic study of harmonics and interharmonics at a modern wind-turbine
2014 (English)In: International Conference on Harmonics and Quality of Power. Proceedings: , p. 718-722, article id 6842921Article in journal (Refereed) Published
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.

National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electric Power Engineering
Identifiers
urn:nbn:se:ltu:diva-34858 (URN)10.1109/ICHQP.2014.6842921 (DOI)2-s2.0-84904283452 (Scopus ID)92aee836-c981-47d3-9785-093e370e66e0 (Local ID)92aee836-c981-47d3-9785-093e370e66e0 (Archive number)92aee836-c981-47d3-9785-093e370e66e0 (OAI)
Conference
International Conference on Harmonics and Quality of Power : 25/05/2014 - 28/05/2014
Note

Godkänd; 2014; 20140806 (johsod); Konferensartikel i tidskrift

Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-08-16Bibliographically approved
Bollen, M., Meyer, J., Amaris, H., Blanco, A. M., Gil-de-Castro, A., Desmet, J., . . . Yang, K. (2014). Future work on harmonics: some expert opinions part I – wind and solar power (ed.). Paper presented at International Conference on Harmonics and Quality of Power : 25/05/2014 - 28/05/2014. , 904-908, Article ID 6842870.
Open this publication in new window or tab >>Future work on harmonics: some expert opinions part I – wind and solar power
Show others...
2014 (English)Article in journal (Refereed) Published
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.

National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electric Power Engineering
Identifiers
urn:nbn:se:ltu:diva-40057 (URN)10.1109/ICHQP.2014.6842870 (DOI)2-s2.0-84904354965 (Scopus ID)f07b890a-7d85-472e-a885-993335bbe8d6 (Local ID)f07b890a-7d85-472e-a885-993335bbe8d6 (Archive number)f07b890a-7d85-472e-a885-993335bbe8d6 (OAI)
Conference
International Conference on Harmonics and Quality of Power : 25/05/2014 - 28/05/2014
Note
Godkänd; 2014; 20140609 (ronsar); Konferensartikel i tidskriftAvailable from: 2016-10-03 Created: 2016-10-03 Last updated: 2018-07-10Bibliographically approved
Meyer, J., Bollen, M., Amaris, H., Blanco, A. M., Castro, A. G., Desmet, J., . . . Yang, K. (2014). Future work on harmonics: some expert opinions part II – supraharmonics, standards and measurements (ed.). Paper presented at International Conference on Harmonics and Quality of Power : 25/05/2014 - 28/05/2014. , 909-913, Article ID 6842871.
Open this publication in new window or tab >>Future work on harmonics: some expert opinions part II – supraharmonics, standards and measurements
Show others...
2014 (English)Article in journal (Refereed) Published
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

National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electric Power Engineering
Identifiers
urn:nbn:se:ltu:diva-34182 (URN)10.1109/ICHQP.2014.6842871 (DOI)2-s2.0-84904359048 (Scopus ID)84df266a-0e88-431d-944a-3bcee50d1540 (Local ID)84df266a-0e88-431d-944a-3bcee50d1540 (Archive number)84df266a-0e88-431d-944a-3bcee50d1540 (OAI)
Conference
International Conference on Harmonics and Quality of Power : 25/05/2014 - 28/05/2014
Note
Godkänd; 2014; 20140609 (ronsar); Konferensartikel i tidskriftAvailable from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-07-10Bibliographically approved
Yang, K. & Bollen, M. (2014). Measurements of Complex Harmonic Current on Two Wind turbines (ed.). Paper presented at International Conference on Renewable Energies and Power Quality : 07/04/2014 - 10/04/2014. The Renewable Energies and Power Quality Journal (RE&PQJ) (12), Article ID 297.
Open this publication in new window or tab >>Measurements of Complex Harmonic Current on Two Wind turbines
2014 (English)In: The Renewable Energies and Power Quality Journal (RE&PQJ), ISSN 2172-038X, E-ISSN 2172-038X, no 12, article id 297Article in journal (Refereed) Published
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electric Power Engineering
Identifiers
urn:nbn:se:ltu:diva-40145 (URN)f240e113-f345-4dc0-81fb-cff24fee3ab7 (Local ID)f240e113-f345-4dc0-81fb-cff24fee3ab7 (Archive number)f240e113-f345-4dc0-81fb-cff24fee3ab7 (OAI)
Conference
International Conference on Renewable Energies and Power Quality : 07/04/2014 - 10/04/2014
Note
Godkänd; 2014; 20140422 (matbol); Konferensartikel i tidskriftAvailable from: 2016-10-03 Created: 2016-10-03 Last updated: 2017-11-30Bibliographically approved
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