Endre søk
Begrens søket
1234567 101 - 150 of 1264
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Treff pr side
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 101.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    CIGRE/CIRED/UIE Joint Working Group C4.110, voltage dip immunity of equipment in installations: main contributions2010Konferansepaper (Fagfellevurdert)
  • 102.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Consumer electronics and the power grid: what are they doing to each other?2013Inngår i: Proceedings 2013 IEEE third International Conference on Consumer Electronics - Berlin (ICCE-Berlin) / [ed] Petra Friedrich, Piscataway, NJ: IEEE Communications Society, 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Consumer electronic devices mostly get their energy from the electric power grid. Such devices might be continuously connected to the grid (like televisions) or only connected to charge the batteries (like cell phones). The amount of energy taken from the grid is not reduced by using devices powered by batteries. Instead, the electrical energy consumption is more likely increased due to the losses in the conversion process and because there are more opportunities to use the device.

  • 103.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Impacts of small units for electricity generation2005Inngår i: First International Conference on Lifestyle, Health and Technology: June 1-3, 2005 at Luleå University of Technology, Porsön, Luleå, Sweden, Luleå: Luleå tekniska universitet, 2005Konferansepaper (Fagfellevurdert)
  • 104.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Is there a place for power quality in the smart grid?2014Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper contains some thoughts on the relations between power quality and smart grids. It includes some of the, in our opinion, important research and development activities that are needed within power quality as part of the transition to the smart grid.

  • 105.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Overvoltages due to wind power: hosting capacity, deterministic and statistical approaches2008Inngår i: Electrical Power Quality and Utilization, ISSN 1234-6799, Vol. 3, nr 2, s. 2-15Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper introduces methods to quantify the impact of wind power and other types of distributed generation on the overvoltage risk. The so-called hosting capacity approach, introduced in the very first issue of this magazine, is used as the basic approach. Both a deterministic and a statistical approach are introduced. The deterministic approach is suitable for generation with a constant production most of the time. However, it is shown that a deterministic approach could easily result in an unnecessary barrier against the introduction of wind power. For any method used to determine the hosting capacity, a serious discussion is needed about overvoltage indices and objectives.

  • 106.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    The smart grid: Adapting the power system to new challenges2011Bok (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    This book links the challenges to which the electricity network is exposed with the range of new technology, methodologies and market mechanisms known under the name "smart grid." The main challenges will be described by the way in which they impact the electricity network: the introduction of renewable electricity production, energy efficiency, the introduction and further opening of the electricity market, increasing demands for reliability and voltage quality, and the growing need for more transport capacity in the grid. Three fundamentally different types of solutions are distinguished in this book: solutions only involving the electricity network (like HVDC and active distribution networks), solutions including the network users but under the control of the network operator (like requirements on production units and curtailment), and fully market-driven solutions (like demand response). An overview is given of the various solutions to the challenges that are possible with new technology; this includes some that are actively discussed elsewhere and others that are somewhat forgotten.Linking the different solutions with the needs of the electricity network, in the light of the various challenges, is a recurring theme in this book.

  • 107.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Voltage dip immunity of equipment and installations2010Inngår i: Electra, ISSN 0212-6222, nr 249, s. 51-56Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This document covers methods to improve the voltage-dip immunity of installations, starting from a detailed description of voltage dips, an overview of the knowledge on equipment immunity, and global voltage-dip statistics. The economics of voltage-dip immunity are discussed. Recommendations for immunity testing are given. A systematic method for designing and improving the immunity of an industrial process is introduced.

  • 108.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Voltage sags2007Inngår i: Electric Power Engineering Handbook: 1. Electric power generation, transmission and distribution, Boca Raton: CRC Press, 2007, 2 edKapittel i bok, del av antologi (Annet (populærvitenskap, debatt, mm))
  • 109.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bahramirad, Shay
    ComEd, Chicago.
    Khodaei, Amin
    University of Denver, Colorado.
    Meyer, Jan
    Dresden University of Technology.
    Langella, Roberto
    Seconda Università di Napoli.
    Hasler, Jean-Philippe
    ABB Corporate Research.
    Zavoda, Francisc
    IREQ.
    Liu, Juncheng
    Xian Boyu Electrical Co.
    Volt-var control and power quality (CIGRE/CIRED C4.24)2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper summarizes the state of discussions in CIGRE/CIRED joined working group C4.24, concerning expected impacts on the power quality of future methods for volt-var-control in the distribution grid. The positive impacts include the reduction of the number of overvoltage and undervoltages and also a reduction of voltage unbalance, when some control schemes are applied. Potential negative impacts include an increased number of short-duration undervoltages, rapid voltage changes, flicker, and voltage transients; a higher risk of harmonic resonances; and increased emission of supraharmonics. All these potential impacts are discussed in the paper.

  • 110.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bengtsson, C
    Nielsen, L.H
    Larsen, P.H
    Mikkelsen, S.D
    Application of regulated shunt reactor for off-shore wind farms2007Konferansepaper (Fagfellevurdert)
  • 111.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Beyer, Y
    Styvactakis, E
    Trhulj, J
    Vailati, R
    Friedl, W
    A European benchmarkning of voltage quality regulation2012Inngår i: 15th International Conference on Harmonics and Quality of Power (ICHQP), IEEE Communications Society, 2012, s. 45-52Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The Council of European Energy Regulators has been publishing Benchmarking Reports on the Quality of Electricity Supply since 2001. For the 2011 edition of the Benchmarking Report the 29 member countries of CEER were joined by the 9 NRA's from the Energy Community and the NRA from Switzerland. This paper contains the main results, findings and recommendations on voltage quality from the 2011 edition.

  • 112.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Castel, Romain
    CRE.
    Friedl, Werner
    E-Control.
    Villa, Ferruccio
    AEEG.
    Baumann, Philippe
    Elcom.
    Esteves, Jorge
    ERSE.
    Larzeni, Samuele
    AEEG.
    Ström, Lars
    EI.
    Beyer, Yvonne
    NMA.
    Faias, Sergio
    ERSE.
    Trhulj, Jasmina
    AERS.
    Guidelines for good practice on voltage quality monitoring2013Inngår i: 22nd International Conference and Exhibition on Electricity Distribution (CIRED 2013): Stockholm, Sweden, 10 - 13 June 2013, Red Hook, NY: Curran Associates, Inc., 2013, artikkel-id 349Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Guidelines are given for setting up and running a voltage quality monitoring programme. These guidelines are published jointly by CEER and ECRB and contain among others recommendations on the number and location of monitors, on disturbances to be monitored and indices to be calculated, on reporting of the results and on financing of the programme. It is concluded that voltage quality monitoring programs are important tools for voltage quality regulation and that all other possible applications should be kept in mind when setting up such a programme. It is also concluded that such programmes should be funded through the network tariffs; that the results should be made available regularly and that diversification of indices and methods is to be avoided.

  • 113.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Cundeva, S
    Etherden, Nicholas
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Yang, Kai
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Considering the needs of the customer in the electricity network of the future2012Konferansepaper (Fagfellevurdert)
    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.

  • 114.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Cundeva, S
    University Sts. Cyrill and Methodias, Skopje.
    Gordon, J.M R
    Djokic, S. Z
    University of Edinburgh.
    Stockman, K
    Ghent University.
    Milanovic, J. V
    University of Manchester.
    Neumann, R
    Qualitrol, Belfast.
    Ethier, G
    Hydro-Québec Research’s Institute.
    Voltage dip immunity aspects of power-electronics equipment: Recommendations from CIGRE/CIRED/UIE JWG C4.1102011Inngår i: 2010 14th International Power Electronics and Motion Control Conference (EPE/PEMC 2010): Ohrid, Macedonia, 6 - 8 September 2010, Piscataway, NJ: IEEE Communications Society, 2011, s. 803-810Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents some of the results from an international working group on voltage-dip immunity. The working group has made a number of recommendations to reduce the adverse impact of voltage dips. Specific recommendations to researchers and manufacturers of powerelectronic equipment are: considering all voltage dip characteristics early in the design of equipment; characterize performance of equipment by means of voltage-dip immunity curves; and made equipment with different immunity available

  • 115.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Cundeva, S.
    University Sts. Cyrill and Methodias, Skopje.
    Gordon, J-M. R.
    Endesa, Sevilla.
    Djokic, S.Z.
    University of Edinburgh.
    Stockman, K.
    Ghent University.
    Milanovic, J.V.
    University of Manchester.
    Neumann, Robert
    Qualitrol, Belfast.
    Ethier, G.
    Hydro-Québec Research’s Institute.
    Voltage dip immunity aspects of power electronics equipment: Recommendations from CIGRE/CIRED/UIE JWG C4.1102011Inngår i: Proceeding of the International Conference on Electrical Power Quality and Utilisation, EPQU, IEEE Communications Society, 2011, s. 803-810Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents some of the results from an international working group on voltage-dip immunity. The working group has made a number of recommendations to reduce the adverse impact of voltage dips. Specific recommendations to researchers and manufacturers of power-electronic equipment are: considering all voltage dip characteristics early in the design of equipment; characterize performance of equipment by means of voltage-dip immunity curves; and made equipment with different immunity available.

  • 116.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Cundeva, S.
    University Sts. Cyrill and Methodias, Skopje.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Yang, Kai
    Yao, L
    Areva T and D, Technology Centre, Stafford.
    A wind park emitting characteristic and non-characteristic harmonics2010Inngår i: 2010 14th International Power Electronics and Motion Control Conference (EPE/PEMC 2010): Ohrid, Macedonia, 6 - 8 September 2010, Piscataway, NJ: IEEE Communications Society, 2010, s. S14-22-S14-26Konferansepaper (Fagfellevurdert)
    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.

  • 117.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Das, Ratan
    IcaPower LLC, Dover, DE.
    Djokic, Sasa Z.
    University of Edinburgh, School of Engineering and Electronics, University of Edinburgh.
    Ciufo, Phil
    University of Wollongong.
    Meyer, Jan
    Institute of Electrical Power Systems and High Voltage Engineering, Technische Universitaet Dresden, Technical University Dresden, Dresden University of Technology.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Zavoda, Francisc
    IREQ, IREQ/HQ, Hydro-Québec Research’s Institute.
    Power Quality Concerns in Implementing Smart Distribution-Grid Applications2017Inngår i: IEEE Transactions on Smart Grid, ISSN 1949-3053, E-ISSN 1949-3061, Vol. 8, nr 1, s. 391-399, artikkel-id 7527692Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper maps the expected and possible adverse consequences for power quality of introducing several smart distribution-grid technologies and applications. The material presented in this paper is the result of discussions in an international CIGRE-CIRED joint working group. The following technologies and applications are discussed: microgrids; advanced voltage control; feeder reconfiguration; and demand-side management. Recommendations are given based on the mapping.

  • 118.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Etherden, Nicholas
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Yang, Kai
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Chang, G. W
    National Chung Cheng University.
    Continuity of supply and voltage quality in the electricity network of the future2012Inngår i: 15th International Conference on Harmonics and Quality of Power (ICHQP), IEEE Communications Society, 2012, s. 375-377Konferansepaper (Fagfellevurdert)
    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.

  • 119.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Gordon, José Romero
    Endesa, Sevilla.
    Djokic, Sasa Z
    University of Edinburgh.
    Stockman, Kurt
    Ghent University.
    Milanovic, Jovica V
    University of Manchester.
    Neumann, Robert
    Qualitrol, Belfast.
    Ethier, Gaetan
    Hydro-Québec Research’s Institute.
    Voltage-dip immunity: statistics and need for further work2010Inngår i: ICREPQ'10, European Association for the Development of Renewable Energies, Environment and Power Quality , 2010Konferansepaper (Fagfellevurdert)
  • 120.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Gu, Irene
    Signal processing of power-quality disturbances2006Bok (Annet (populærvitenskap, debatt, mm))
  • 121.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Gu, Irene Y.H.
    Eindhoven University of Technology.
    Santoso, Surya
    University of Texas, Austin.
    McGranaghan, Mark F.
    University of Manchester.
    Crossley, Peter A.
    University of Manchester.
    Ribeiro, Moises V
    Universidade Federal de Pernambuco, Recife.
    Ribeiro, Paulo F.
    Universidade Federal de Pernambuco, Recife.
    Bridging the gap between signal and power2009Inngår i: IEEE signal processing magazine (Print), ISSN 1053-5888, E-ISSN 1558-0792, Vol. 26, nr 4, s. 12-31Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Signal processing has been used in many different applications, including electric power systems. This is an important category, since a wide variety of digital measurements is available and data analysis is required to deliver diagnostic solutions and correlation with known behaviors. Measurements are taken at numerous locations, and the analysis of data applies to a variety of issues in ¿ power quality (PQ) and reliability ¿ power system and equipment diagnostics ¿ power system control ¿ power system protection. This article focuses on problems and issues related to PQ and power system diagnostics, in particular those where signal processing techniques are extremely important. PQ is a general term that describes the quality of voltage and current waveforms. PQ problems include all electric power problems or disturbances in the supply system that prevent end-user equipment from operating properly. Examples of voltage and current variations that can result in PQ problems include voltage interruptions, long- and short-duration voltage variations, steady-state research opportunities that use the measured voltages and currents to indicate possible equipment and system problems (referred to as equipment diagnostics).

  • 122.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Gu, I.Y.H
    Analysis and classification of power quality disturbances: ideas, methods and techniques2006Inngår i: 12th International Conference on Harmonics and Quality of Power, 2006Konferansepaper (Fagfellevurdert)
  • 123.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Gu, I.Y.H.
    Characterization of voltage variations in the very-short time-scale2005Inngår i: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 20, nr 2, s. 1198-1199Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This letter presents a method for characterizing the fast voltage variations that occur on a time scale between the subsecond fluctuations covered by the flickermeter standard and the 10-min values covered by standards like EN 50160 The method is fully compatible with IEC 61000-4-30 class A. The new characteristic is correlated to small switching actions, such as domestic load switching and transformer tap-changer operation.

  • 124.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Gu, I.Y.H
    Chalmers University of Technology, Department of Signals and Systems.
    On the analysis of voltage and current transients in three-phase power systems2007Inngår i: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 22, nr 2, s. 1194-1201Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper proposes a method for analyzing measurements of voltage transients in three-phase systems. The method is based on the Clarke transform introduced in 1950 for calculations of travelling waves along three-phase transmission lines. The proposed method also shows close similarities with the classification of three-phase unbalanced voltage dips. After extracting the actual transient (e.g., by using a notch filter centered on the power-system frequency), the three signals are decomposed into seven components. From the relation between these seven components, the dominant component is identified. The method is successfully applied to a number of measured transients. The paper also identifies the limitations of the method and gives suggestions for future work

  • 125.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Gu, I.Y.H
    Chalmers University of Technology, Department of Signals and Systems.
    Axelberg, P.G.V
    Chalmers University of Technology, Department of Signals and Systems.
    Styvaktakis, E
    Hellenic Transmission System Operator.
    Classification of underlying causes of power quality disturbances: deterministic versus statistical methods2007Inngår i: EURASIP Journal on Advances in Signal Processing, ISSN 1687-6172, E-ISSN 1687-6180Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents the two main types of classification methods for power quality disturbances based on underlying causes: deterministic classification, giving an expert system as an example, and statistical classification, with support vector machines (a novel method) as an example. An expert system is suitable when one has limited amount of data and sufficient power system expert knowledge; however, its application requires a set of threshold values. Statistical methods are suitable when large amount of data is available for training. Two important issues to guarantee the effectiveness of a classifier, data segmentation, and feature extraction are discussed. Segmentation of a sequence of data recording is preprocessing to partition the data into segments each representing a duration containing either an event or a transition between two events. Extraction of features is applied to each segment individually. Some useful features and their effectiveness are then discussed. Some experimental results are included for demonstrating the effectiveness of both systems. Finally, conclusions are given together with the discussion of some future research directions.

  • 126.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Hassan, F
    Yang, Y
    Limitations set by the distribution network against the large-scale integration of distributed energy resources2008Konferansepaper (Annet vitenskapelig)
  • 127.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Hassan, Fainan
    Integration of distributed generation in the power system2011Bok (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    Distributed Generation (DG) reduces the amount of energy lost in transmitting electricity because the electricity is generated very near where it is used. This book introduces systematic and transparent methods for quantifying the impact of DG on the power grid. It emphasizes systematic and transparent calculation methods, allowing for a quantification of the amount of DG that can be integrated at a certain location of the grid or in the grid as a whole. It also provides an overview of the different energy sources, with emphasis on wind power, solar power and combined heat and power in the power grid.

  • 128.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Holm, A
    He, Y
    Owe, P
    A customer-oriented approach towards reliability indices2007Inngår i: Conference proceedings: 19th International Conference and Exhibition on Electricity Distribution : Vienna, 21 - 24 May 2007, Liege: AIM , 2007Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper introduces a reliability index that is directly linked to the satisfaction of individual customers with the experienced reliability of supply. The definition of the index is based on the observation that customers are satisfied as long as they have less than 3 interruptions per year, none of which lasts longer than 8 hours. The customer dissatisfaction index (CDI) is defined as the probability that this condition is fulfilled for a given customer. Mathematical expressions are obtained for the CDI; its relation with existing indices is studied; and the results of a case study in a medium-voltage distribution network are presented.

  • 129.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Hooshyar, Hossein
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Spread of high frequency current emission2013Inngår i: 22nd International Conference and Exhibition on Electricity Distribution (CIRED 2013): Stockholm, Sweden, 10 - 13 June 2013, Red Hook, NY: Curran Associates, Inc., 2013, artikkel-id 209Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper investigates the spread of the high frequency current emission between devices of different size and the grid. The impact of the EMC filter, either LCL or CLC configuration, has been considered from a simplified model. The high frequency current emission, produced by a large device, can potentially cause a relatively large current flowing through a nearby small device. An important conclusion from the study is that current amplification can occur due to harmonic resonances between different types of filters.

  • 130.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Häger, Mats
    Power quality: interactions between distributed energy resources,the grid, and other customers2005Inngår i: Leonardo EnergyArtikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    This paper presents the three aspects of power quality concerning distributed energy resources (DER). The voltage quality experienced by a DER unit impacts the performance of the unit: bad voltage quality may reduce the life length of the unit and lead to incorrect operation or tripping. The DER unit's current (the "current quality" impacts the system and through the system other customers. The hosting-capacity concept is proposed as a systematic method for quantifying the impact of DER units. The third aspect of power quality only appears with large (local or global) penetration of DER. The tripping of DER units on voltage dips or frequency swing endangers the reliability, stability and security of the system.

  • 131.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Häger, Mats
    What is reliability?: Reliability and reliability indices in the viewpoint of the network operator and in the viewpoint of the customer2006Inngår i: Electrical Power Quality and Utilization, ISSN 1234-6799, Vol. 2, nr 2Artikkel i tidsskrift (Annet vitenskapelig)
  • 132.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Häger, Mats
    Olofsson, M
    Allocation of emission limits for individual emitters at different voltage levels: flicker and harmonics2010Konferansepaper (Fagfellevurdert)
  • 133.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Karlsson, Daniel E.
    STRI AB, Ludvika.
    Lennerhag, Oscar
    STRI AB, Sweden.
    Different Fault Types and Voltage Dips in relation to Shielding of Subtransmission Lines2016Inngår i: 2016 17th International Conference on Harmonics and Quality of Power, Piscataway, NJ, 2016, s. 518-523, artikkel-id 7783470Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents a method for considering the voltage-dip performance of the power system in the design of subtransmission lines. The shielding performance of the lines is expressed in terms of the number of faults for different number of phases involved in the fault. Relations between fault type and voltage dip at the terminals of sensitive equipment are used to determine the resulting number of equipment trips. The method is illustrated by applying it to three different tower designs used in the Swedish subtransmission networks. It is shown that the installation of shield wires significantly reduces the number of equipment trips, especially in combination with the installation of additional capacitance in adjustable-speed drives.

  • 134.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lundmark, Martin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Boije, Christer
    Åkerlund, John
    A short note on calculating power for energy-efficient lighting and other non-linear loads2009Rapport (Annet vitenskapelig)
  • 135.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lundmark, Martin
    Boije, Christer
    Åkerlund, John
    Kort genomgång av effektberäkningar för lågenergilampor och andra olinjära laster2009Rapport (Annet vitenskapelig)
  • 136.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    McMichael, Ian
    Power Quality Solution.
    Stephens, Mark
    EPRI.
    Stockman, Kurt
    Hogeschool West, Vlaanderen, Kortrijk.
    Djokic, Sasa
    University of Edinburgh.
    Zavoda, Francisc
    IREQ.
    Brumsickle, Bill
    Soft Switchning Technology.
    McEachern, Alex
    Power Standards Lab.
    Gordon, José Romero
    Endesa, Sevilla.
    Ethier, Gaetan
    Hydro-Québec Research’s Institute.
    Neumann, Robert
    Qualitrol.
    CIGRE/CIRED/UIE JWG C4.110 - Voltagedip immunity of equipment in installations: status April 20082008Inngår i: 2008 13th International Conference on Harmonics and Quality of Power: [ICHQP 2008] ; Wollongong, Australia, 28 September - 1 October 2008, Piscataway, NJ: IEEE Communications Society, 2008Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents the status of the work, by April 2008, in C4.110, a joint working group by CIGRE, CIRED and UIE. The scope of the working group is to gather technical knowledge on the immunity of equipment, installations and processes against voltage dips, and to use this knowledge in the further development of methods and standards. The activities of the working group are divided in seven "chapters". Chapters 1 and 7 are introduction and conclusions, respectively. Chapter 2 gives a general description of voltage dips as they appear at the terminals of sensitive equipment. Chapter 3 describes the performance of equipment and processes during voltage dips. This chapter also includes recommendations on the design of processes. In Chapter 4 the results from Chapter 2 and Chapter 3 are combined to set requirements for the dip characteristics that should be included in immunity testing. Chapter 5 is the data gathering chapter, covering data on voltage-dip statistics at different locations, but also data on the economics of equipment immunity and testing. Finally, in Chapter 6, recommendations for immunity objectives will be given. Important contributions of the working group are: a check-list of voltage dip characteristics to be used early in the design of equipment; a methodology to assess the performance of a complete installation and to include voltage-dip performance in the design of the installation; recommendations for characterization testing of equipment against voltage dips; recommendations for voltagedip immunity of equipment.

  • 137.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    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 tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Yang, Kai
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Future work on harmonics: some expert opinions part I – wind and solar power2014Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 138.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Milanovic, J. V
    University of Manchester.
    Čukalevski, N
    Mihailo Pupin Institute.
    CIGRE/CIRED JWG C4.112: Power Quality Monitoring2014Konferansepaper (Fagfellevurdert)
  • 139.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Mousavi-Gargari, S
    Harmonic resonances due to transmission cables2014Konferansepaper (Fagfellevurdert)
  • 140.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Mousavi-Gargari, S
    Tennet, P.O.Box 718, 6800 AS Arnhem.
    Bahramirad, S
    ComEd, Chicago.
    Harmonic resonances due to transmission-system cables2014Inngår i: The Renewable Energies and Power Quality Journal (RE&PQJ), ISSN 2172-038X, E-ISSN 2172-038X, nr 12, artikkel-id 463Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper gives some examples of harmonicissues that can occur when long ac cables are connected in thetransmission grid. The main impact is that resonances can occurat much lower frequencies than when only overhead lines arepresent. Two illustrative case studies are presented: one for a275-kV cable, one for a 400-kV cable in combination with a 132-kV capacitor bank. A simple rule-of-thumb is given, to decide ifa detailed harmonic study is needed. Some guidelines for such astudy are given as well.

  • 141.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Mulenga, Enock
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Etherden, Nicholas
    Hosting Capacity of the Grid for Photovoltaic Installations: a Stochastic Approach Applied to Single-phase Connections2018Inngår i: 8th Solar Integration Workshop, 2018, s. 1-7, artikkel-id 6A_1_SIW18_046Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper discusses the voltage rise due to PV installations connected to a low-voltage network. The connection of individual installations is studies for both single-phase and three-phase connection. A stochastic method is presented to estimate the hosting capacity. This method is illustrated for random and coordinated connection of single-phase installations. It is shown, in a number of ways, that the installation of large (e.g. 6 kW) single-phase connected units can easily result in unacceptable overvoltages.

  • 142.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Olofsson, Magnus
    Elforsk.
    Consumer electronics and the power grid: what are they doing to each other?2015Inngår i: I E E E Consumer Electronics Magazine, ISSN 2162-2248, Vol. 4, nr 1, s. 50-57, artikkel-id 6985955Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Consumer electronic devices mostly get their energy from the electric power grid. Such devices might be continuously connected to the grid (like televisions) or only connected to charge the batteries (like cell phones). The amount of energy taken from the grid is not reduced by using devices powered by batteries. Instead, the electrical energy consumption is more likely increased due to the losses in the conversion process and because there are more opportunities to use the device.

  • 143.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Olofsson, Magnus
    Elforsk.
    Larsson, Anders
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lundmark, Martin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Standards for supraharmonics (2 to 150 kHz)2014Inngår i: IEEE Electromagnetic Compatibility Magazine, ISSN 2162-2264, Vol. 3, nr 1, s. 114-119Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    There is a serious interest from the international standard-setting community in knowledge about voltage and current distortion in the frequency range 2 to 150 kHz, referred to as supraharmonics. At the same time, research is ongoing at a number of locations, but the knowledge about supraharmonics remains limited. This paper compares some of the properties of harmonics and supraharmonics. An increase in supraharmonics for individual devices is observed in association with a decrease in harmonic emission (i.e. below 2 kHz). A proposal is made for setting limits in this frequency range. The proposal is based on existing standards and is meant to be for discussion. The authors strongly encourage an open discussion about the proposed limits. There are a number of differences between harmonics and supraharmonics that are not covered by the proposed set of limits. A substantial amount of further research is needed to extend the standard framework for supraharmonics such that this can be covered by standards

  • 144.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Ribeiro, Paulo F.
    The smart grid concept evolution2013Inngår i: Standard handbook for electrical engineers, New York: McGraw-Hill Companies , 2013, 16Kapittel i bok, del av antologi (Fagfellevurdert)
  • 145.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Ribeiro, Paulo
    Calvin College, Grand Rapids, MI.
    Gu, Irene Y H
    Chalmers University of Technology.
    Duque, Carlos A.
    Federal University of Juiz de Fora, Minas Gerais.
    Trends, challenges and opportunities in power quality research2010Inngår i: European transactions on electrical power, ISSN 1430-144X, E-ISSN 1546-3109, Vol. 20, nr 1, s. 3-18Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper outlines a number of possible research directions in power quality. The introduction of new sources of generation will introduce the need for new research on voltage-magnitude variations, harmonic emission and harmonic resonance. Statistical performance indicators are expected to play an important role in addressing the hosting capacity of the power system for these new sources. The quickly growing amounts of power-quality data call for automatic analysis methods. Advanced signal-processing tools need to be developed and applied to address this challenge. Equipment with an active power-electronic interface generates waveform distortion at higher frequencies than existing equipment. The emission, spread, consequences and mitigation of this distortion require more research emphasis. The growing complexity of the power system calls for remote identification of system events and load transitions. Future DC networks, at different voltage levels, require the research on DC power quality next to AC power quality. Research on methods to describe and analyse time-varying harmonics has applications in a number of the above-mentioned issues. So does the use of hardware-in-the-loop (HIL) and real-time-digital simulation. Existing power quality standards should not form a barrier against future research; instead research should result in improved standards as well as completely new concepts. Examples are: voltage dips in three-phase systems, flicker due to non-incandescent lamps, and voltage variations on the timescale between 1 second and 10 minutes. All together, it is concluded in this paper that sufficient important and interesting research challenges and opportunities remain in the power quality area.

  • 146.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Ribeiro, Paulo
    Calvin College, Grand Rapids, MI.
    Larsson, Anders
    Lundmark, Martin
    Limits for voltage distortion in the frequency range 2 to 9 kHz2008Inngår i: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 23, nr 3, s. 1481-1487Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper addresses voltage distortion in the frequency range 2 to 9 kHz, above what is normally considered in harmonic studies. By extrapolating the voltage-distortion limits that exist in international standards for distortion up to 2 kHz, it is concluded that 0.5% of nominal voltage per 200-Hz band is a safe limit. This limit is next used to estimate the number of small generator units (1-10 kW) that can be connected to a low-voltage grid. It is concluded that in some cases the connection of one or just a few units already leads to a distortion level above the limit.

  • 147.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Hosting Capacity of the Power Grid for Renewable Electricity Production and New Large Consumption Equipment2017Inngår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 10, nr 9, artikkel-id 1325Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    After a brief historical introduction to the hosting-capacity approach, the hosting capacity is presented in this paper as a tool for distribution-system planning under uncertainty. This tool is illustrated by evaluating the readiness of two low-voltage networks for increasing amounts of customers with PV panels or with EV chargers. Both undervoltage and overvoltage are considered in the studies presented here. Probability distribution functions are calculated for the worst-case overvoltage and undervoltage as a function of the number of customers with PV or EV chargers. These distributions are used to obtain 90th percentile values that act as a performance index. This index is compared with an overvoltage or undervoltage limit to get the hosting capacity. General aspects of the hosting-capacity calculations (performance indices, limits, and calculation methods) are discussed for a number of other phenomena: overcurrent; fast voltage magnitude variations; voltage unbalance; harmonics and supraharmonics. The need for gathering data and further development of models for existing demand is emphasised in the discussion and conclusions

  • 148.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Modelling and simulation issues resulting from extended measurements2015Inngår i: 2015 IEEE Power & Energy Society General Meeting: 26-30 July 2015, Denver CO, Piscataway, NJ: IEEE Communications Society, 2015, artikkel-id 7285961Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Presents a collection slides covering the following topics: supraharmonics propagation; measurement modeling; grid supply terminals; device terminals; secondary emission; primary emission; voltage measurement and capacitor

  • 149.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Nya lågspänningslaster och störningar i frekvensområdet 2 till 150 kHz: resultat från forskningsprojektet vid Luleå tekniska universitet, samt en kartläggning av behovet på ytterligare forskning2011Rapport (Annet vitenskapelig)
  • 150.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Primary and Secondary Harmonics Emission: Harmonic interaction - A set of definitions2016Inngår i: 2016 17th International Conference on Harmonics and Quality of Power, Piscataway, NJ: IEEE Computer Society, 2016, s. 703-708, artikkel-id 7783333Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper proposes a set of definitions to simplify the discussion about the different contributions to the harmonic currents at the terminals of a device or an installation. Definitions are given, and explained, for 'primary harmonic emission', 'secondary harmonic emission', and 'harmonic interaction'

1234567 101 - 150 of 1264
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf