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  • 301.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Bollen, Math
    Harmonic emission before and after changing to LED and CFL: Part I: Laboratory measurements for a domestic customer2010Inngår i: 14th International Conference on Harmonics and Quality of Power (ICHQP), Piscataway, NJ: IEEE Communications Society, 2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents an investigation after the impact on a number of power-quality parameters due to the change from incandescent lamps to energy saving lamps like CFL and LED. The measurements were conducted in a full-scale laboratory model with ordinary household equipment connected, thus simulating an ordinary domestic customer. Incandescent lamps have been replaced in stages by CFL and LED lamps. The CFL's and LED lamps will contribute to an increase in current distortion but the amplitude of the harmonics is quite low so the change of lighting will only have a minor effect on the total current harmonic distortion. It is also shown that the (total) power factor is not a good indicator to compare the impact of different loads on the system.

  • 302.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Bollen, Math
    Harmonic emission before and after changing to LED and CFL: Part II: Field Measurements for a hotel2010Inngår i: 14th International Conference onHarmonics and Quality of Power (ICHQP), Piscataway, NJ: IEEE Communications Society, 2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper shows the results of measurements performed with a medium-sized hotel in the North of Sweden. The harmonic emission and other parameters were measured before, during and after a replacement of all incandescent lamps with energy saving lamps, both compact fluorescent lamps (CFL's) and light emitting diodes (LED's). it was not possible to see any major difference in harmonic spectrum before and after the replacement. The reduction in power factor that was observed was completely due to the reduction in active power.

  • 303.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Harmonic emission before and after changing to LED lamps: Field measurements for an urban area2012Inngår i: 15th International Conference on Harmonics and Quality of Power (ICHQP), IEEE Communications Society, 2012, s. 552-557Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The paper presents measurements performed in an urban area in the north of Sweden with two individual houses and on LV side of the distribution transformer supplying these two and ten more houses. Measurements of harmonic and interharmonic groups were performed before and after replacing all existing (mainly incandescent) lamps in all 12 houses with LED lamps. The total power of all lamps was reduced from approximately 2300 W to approximately 450 W, per house. All new lamps were low-power-factor lamps. The paper shows the variations of the most important harmonics with time and relevant spectra before and after the replacement. The emission during the evening hours is studied in specific detail. Despite the low power factor of the individual lamps, no change in emission due to the lamps has been observed, neither for any of the two individual houses nor the distribution transformer supplying all 12 houses

  • 304.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Interaction between narrowband power-line communication and end-user equipment2011Inngår i: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 26, nr 3, s. 2034-2039Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper discusses some of the electromagnetic-compatibility issues concerning the use of power lines for communication. Based on a series of measurements performed in a laboratory environment and in the field, five different types of interactions between communication and end-user equipment are distinguished. Measurement examples are shown for several of these types. It is concluded that the creation of a low-impedance path by end-user equipment is the main cause of interference.

  • 305.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Laboratory and field measurements of harmonic emission from energy-efficient lamps2011Inngår i: Proceedings of CIRED 21st International Conference on Electricity Distribution, 2011, artikkel-id 0172Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents measurements of the harmonic current distortion before and after the replacement of all incandescent lamps with compact fluorescent and LED lamps. Measurements were performed in the laboratory for a physical full-scale model of a residential customer; field measurements were performed for a hotel. In all cases the lamps used were low-power-factor ones (0.6 power factor). The emulated domestic customer showed a small increase in harmonic emission; for the hotel no difference in emission was noticeable before and after the replacement.

  • 306.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Total conducted emission from a customer in the frequency range 2 to 150 kHz with different types of lighting2011Inngår i: Proceedings of CIRED 21st International Conference on Electricity Distribution, 2011, artikkel-id 0173Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Harmonic studies in almost all cases are limited to the frequency range up to 2 or 2.5 kHz. In the frequency range above 2 kHz, almost no standards exist and measurements are rare. This paper presents measurements of the emission from a total installation in the frequency range 2 to 150 kHz. A physical model (electrically full-scale) of a domestic customer was built in the laboratory. Field measurements were performed on a medium-sized hotel. The impact of different types of lighting is shown to be small.

  • 307.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Bollen, Math
    Larsson, Anders
    Lundmark, Martin
    Measurement of interaction between equipment in the frequency range 9 to 95 kHz2009Inngår i: CIRED 20th International Conference on Electricity Distribution: (CIRED 2009) ; Prague, Czech Republic, 8 - 11 June 2009, Red Hook, NY: Curran Associates, Inc., 2009, s. 231-234Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A number of measurements have been performed on a full-scale electric model of a house to study equipment emission and impedances in the frequency range 9-95 kHz. Most equipment forms a much lower impedance path that the grid. The result is that conducted disturbances in this frequency range mainly flow between individual devices instead of between devices and the grid. It is also shown that the input impedance of equipment can be highly time dependent at a time scale below one cycle of the power-system frequency.

  • 308.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Bollen, Math
    Lundmark, Martin
    Equipment currents in the frequency range 9-95 kHz, measured in a realistic environment2008Inngår 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]

    A number of measurements have been performed on a full-scale electric model of a house to examine how enduser equipment affect the impedance in the frequency range 9-95 kHz. It is shown that the impedance level for the grid itself is fairly high and that it decreases when end-user equipment is connected. End-user equipment can be divided in to different categories, loads for which impedance is constant over time (for one cycle) and frequency and loads for which impedance varies over time, frequency or both. The measurements indicate that currents in high frequencies travel between loads at a much higher degree than between the load and the transformer.

  • 309.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Lundmark, Martin
    Nätpåverkan av lågenergibelysning2009Rapport (Annet vitenskapelig)
  • 310.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Bollen, Math
    Lundmark, Martin
    Åkerlund, John
    Boije, Christer
    Nätpåverkan av lågenergibelysning: populär version2009Rapport (Annet (populærvitenskap, debatt, mm))
  • 311.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Larsson, Anders
    Bollen, Math
    Lundmark, Martin
    Interaction between equipment and power line communication: 9-95 kHz2009Inngår i: 2009 IEEE Bucharest PowerTech Proceedings / [ed] Mircea Eremia, IEEE Communications Society, 2009Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents detailed measurements of currents flowing between modern electronic devices in a domestic environment. The results shown in this paper cover the frequency range 9 to 95 kHz, being the frequency band dedicated to power-line communication by network operators. Large differences exist between different devices, even when they are of the same type. It is also shown that the voltage waveform and the emission by other equipment have a significant impact on the current flowing between a device and the grid. An important conclusion from the measurements is that the high-frequency currents mainly flow between neighbouring devices.

  • 312.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Yang, Kai
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Gil-de-Castro, Aurora
    Waveform distortion: a comparison of photovoltaic and wind power2014Artikkel i tidsskrift (Fagfellevurdert)
    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

  • 313.
    Sabin, Daniel
    et al.
    Electrotek Concepts, Inc., Beverly, MA,.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Overview of IEEE Std 1564-2014 Guide for Voltage Sag Indices2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    IEEE Std 1564-2014 Guide for Voltage Sag Indices is a new standard that identifies appropriate voltage sag indices and characteristics of electrical power and supply systems as well as the methods for their calculation. This paper presents an overview of IEEE Std. 1564-2014. It summarizes the IEEE 1564 methods for quantifying the severity of individual voltage sag events, for quantifying the performance at a specific location via single-site indices, and for quantifying the system performance via system indices. The methods are appropriate for use in transmission, distribution, and utilization electric power systems.

  • 314.
    Sabin, Daniel Daniel
    et al.
    Electrotek Concepts, Inc., Beverly, MA,.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Overview of IEEE std 1564-2014 guide for voltage sag indices2014Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    IEEE Std 1564-2014 Guide for Voltage Sag Indices is a new standard that identifies appropriate voltage sag indices and characteristics of electrical power and supply systems as well as the methods for their calculation. This paper presents an overview of IEEE 1564, which was approved as a new standard by IEEE RevCom in March 2014. The paper summarizes the IEEE 1564 methods for quantifying the severity of individual voltage sag events, for quantifying the performance at a specific location via single-site indices, and for quantifying the performance via system indices. Multiple methods are presented for each. The methods are appropriate for use in transmission, distribution, and utilization electric power systems.

  • 315.
    Sakar, Selcuk
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Immunity Test of LED Lamps Based on IEC 61000-4-19 and Unexpected Consequence2018Inngår i: Proceedings of International Conference on Harmonics and Quality of Power, ICHQP, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    ED lighting technology is the most efficient way oflighting service and its usage has increased rapidly. Although,LED lamps are potential victim and source of electromagneticinterference in the frequency range between 2 kHz and 150 kHz(“supraharmonics”). Therefore, immunity test for this frequencyrange is necessary to analyze its performance variations. In thisstudy, Test profiles described in IEC 61000-4-19 have beenapplied to LED lamps and the results have been analyzedaccording to implemented algorithm that uses the relative lightintensity variation index. The results show that bothsupraharmonics and modulation of the test profiles can reveallight flicker. In addition, some potential drawbacks of thestandard have been found that deviation of the mains’ frequencyis also another factor causes intermodulation/nonsynchronizationon the applied test signal, so this can be seen aslight flicker. This issue better be clarified with more details in theIEC 61000-4-19, particalulary for lighting equipment.

  • 316.
    Sakar, Selcuk
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Interferences in AC-DC LED Drivers Exposed to Voltage Disturbances in the Frequency Range 2 kHz - 150 kHz2019Inngår i: IEEE transactions on power electronics, ISSN 0885-8993, E-ISSN 1941-0107, Vol. 34, nr 11, s. 11171-11181Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    LED lamps are both potential victims and sources of electromagnetic disturbances in the frequency range between 2 kHz and 150 kHz (“supraharmonics”). Immunity tests for this frequency range are important due to possible performance degradation of light intensity with LED lamps. In this paper, the impact of supraharmonics (SHs) on light intensity from LED lamps has been analyzed. LED lamps have been exposed to supraharmonic test profiles based on IEC 61000-4-19. Three phenomena that impact light intensity metrics have been observed and explained by models: (1) earlier conduction/later blocking caused by supraharmonic voltage, (2) intermittent conduction depending on the supraharmonic impedance of the LED driver and (3) reverse-recovery current of the diodes at higher frequency. It is observed that impact on the light intensity metrics shows up around the beginning and end of the conduction period. The results reveal that the profile of the supraharmonic voltage could cause deviations in the modulation depth and the average light intensity. The immunity of LED lamps against SHs shall be further studied and discussed by research groups and standard committees.

  • 317.
    Sakar, Selcuk
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Light Intensity Behavior of LED Lamps within theThermal Stabilization Period2018Inngår i: Proceedings of International Conference on Harmonics and Quality of Power, ICHQP, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Visible changes in the light intensity of lamps, referredto as flicker, are quantified based on definitions such asnormalized gain factor and relative light intensity variation.However, those values also change depending on the time after anLED lamp has been switched on. An experiment has been carriedout to analyze this phenomenon. A new metric, a “thermalstabilization time”, has been proposed to identify the time toreach steady state light intensity. Although rare, the change inlight intensity can reach up to 68% during the thermalstabilization time. Consequently, acquiring data at differentintervals can lead to incorrect estimation of critical metrics.Stabilization is an essential factor that should be taken intoconsideration in LED lamps’ measurement. It is recommended bythe authors that 60-minute operation is required before acquiring data.

  • 318.
    Sakar, Selcuk
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Light intensity immunity performance of LED street lamps under power quality disturbances2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    An increasing application of LED street lamps brings out an important question regarding their immunity against power quality disturbances. The behaviour of commonly used lighting equipment such as incandescent lamps, compact fluorescent lamps (CFL), and gas-discharge lamps is known. However, knowledge on immunity of LED based lighting equipment is still limited, particularly in street lighting aspect. In this paper, immunity of LED street lamps is determined for voltage dips, short interruptions, voltage fluctuations and supraharmonics. A series of experiments has been performed with respect to test levels defined in IEC 61000-4-11, IEC 61000-4-15 and IEC 61000-4-19. Voltage dips and short interruptions cause higher short-term light flicker severity values that might lead to unintended consequences for car drivers and pedestrians. Interharmonics can result in light flicker, but the impact is very limited, only one lamp exceeds the limits. Supraharmonics impact the current but have minor impact on the visible light. The supraharmonic current can be 25 times nominal. This could decrease the lifetime of equipment

  • 319.
    Santos, Ivan N.
    et al.
    UFU.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Ribeiro, Paulo F.
    UNIFEI.
    Exploring the Concept of Hosting Capacity for Harmonic Distortions Assessment2015Inngår i: 2015 IEEE Power & Energy Society General Meeting: 26-30 July 2015, Denver CO, Piscataway, NJ: IEEE Communications Society, 2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

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

  • 320.
    Santos, Ivan Nunes
    et al.
    Federal University of Uberlândia.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Ribeiro, Paulo Fernando
    Federal University of Itajubá.
    Methodology for estimation of harmonic hosting2014Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The increasing penetration of distributed generation with non-linear characteristics demands a clear methodology for determining the amount of generation that can be connected to the system without deteriorating the performance. This paper proposes a methodology for determining the hosting capacity regarding harmonic distortions. To exemplify an application of the proposed procedure, a simple case study is performed and analyzed.

  • 321.
    Santos, Ivan Nunes
    et al.
    Federal University of Uberlândia.
    Ćuk, Vladimir
    Eindhoven University of Technology.
    Almeida, Pedro M.
    Federal University of Juiz de Fora, Minas Gerais.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Ribeiro, Paulo Fernando
    Federal University of Itajubá, Universidade Federal de Pernambuco, Recife, Calvin College, Grand Rapids, MI.
    Considerations on hosting capacity for harmonic distortions on transmission and distribution systems2015Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 119, s. 199-206Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

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

  • 322.
    Schwanz, Daphne
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bagheri, Azam
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Larsson, Anders
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Active harmonic filters: control techniques review2016Inngår i: 17th International Conference on Harmonics and Quality of Power, Piscataway, NJ, 2016, s. 36-41, artikkel-id 7783423Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The use of active filters for harmonic mitigation compensation is increasing together with the improvement of their control techniques. Depending on the situation, the use of one technique instead of the other makes the difference of achieving a better harmonic mitigation or not. In this paper, a review of control techniques related to harmonic filters for harmonic mitigation is presented, together with the advantages and disadvantages. From the literature review it was observed that new techniques are being used and classical ones are being improved.

  • 323.
    Schwanz, Daphne
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Larsson, Anders
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    A Review of Solutions for Harmonic Mitigation2016Inngår i: 2016 17th International Conference on Harmonics and Quality of Power, Piscataway, NJ: IEEE Computer Society, 2016, s. 30-35, artikkel-id 7783422Konferansepaper (Fagfellevurdert)
    Abstract [en]

    With the increasing of non-linear equipments connected in the network, mitigation solutions are needed to avoid and solve harmonic and resonance problems that may damage equipments and avoid their connection into the grid. Several are the solutions given to this problem; however, not all them are suitable for all situations. For it, in this paper a review of the most used harmonic solutions and some new technologies are presented. The advantages and disadvantages are described and the most used passive, active and hybrid solutions are described

  • 324.
    Schwanz, Daphne
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Larsson, Anders
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Secondary Harmonic Emission in Wind Power Plants,2019Konferansepaper (Fagfellevurdert)
  • 325.
    Schwanz, Daphne
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Larsson, Anders
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Some methods for harmonic emission determination in wind power plants2018Inngår i: Proceedings of International Conference on Harmonics and Quality of Power, ICHQP, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The connection of new installations, as wind power plants, into the public grid requires that some conditions are fulfilled. Their aim is among others to ensure a proper power quality in the grid and to ensure a high probability of electromagnetic compatibility. The harmonic emission of individual sources is one of the power quality concerns, because they can damage and increase heating in devices. However, as there are other power electronics loads are connected, the correct assessment of the harmonic emission from one specific source is not straightforward. in this paper, a review of the most used methods for harmonic emission determination is presented and some considerations are discussed regarding their use in wind power plants harmonic contribution. Depending on the application, one method is more suitable than the other. However, assumptions are necessary with any method, especially for the harmonic impedances. For wind power plants not all the presented methods are suitable. Also, further investigations are needed to determine the harmonic impedance of the wind power plant and public grid, especially around resonant frequencies.

  • 326.
    Schwanz, Daphne
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Larsson, Anders
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Kocewiak, Łukasz Hubert
    DONG Energy Wind Power, Fredericia.
    Harmonic Mitigation in Wind Parks: Active Filter Solutions2016Inngår i: 2016 17th International Conference on Harmonics and Quality of Power, 2016, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2016, s. 220-225Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Passive solutions are the most used harmonic mitigation methods in wind power plants, but the use of active filters is also a suitable and attractive approach. However, the best location for the connection of these active filters needs to be studied and evaluated. In this paper, a study of the use of active harmonic filters placed at different locations inside a wind power plant is performed. The results for current and voltage harmonic distortion are compared and discussed to determine the most suitable location for placing active harmonic filters within a wind power plant

  • 327.
    Schwanz, Daphne
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Larsson, Anders
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Kocewiak, Łukasz Hubert
    DONG Energy Wind Power, Fredericia.
    Harmonic mitigation in wind power plants: Active filter solutions2016Inngår i: 17th International Conference on Harmonics and Quality of Power, Piscataway, NJ, 2016, s. 220-225, artikkel-id 7783321Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Passive solutions are the most used harmonic mitigation methods in wind power plants, but the use of active filters is also a suitable and attractive approach. However, the best location for the connection of these active filters needs to be studied and evaluated. In this paper, a study of the use of active harmonic filters placed at different locations inside a wind power plant is performed. The results for current and voltage harmonic distortion are compared and discussed to determine the most suitable location for placing active harmonic filters within a wind power plant

  • 328.
    Schwanz, Daphne
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Obalans från enfasanslutna solpaneler2015Rapport (Fagfellevurdert)
  • 329.
    Schwanz, Daphne
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Busatto, Tatiano
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Larsson, Anders
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    A stochastic study of harmonic voltage distortion considering single-phase photovoltaic inverters2018Inngår i: Proceedings of International Conference on Harmonics and Quality of Power, ICHQP, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, the hosting capacity considering harmonic distortion is estimated for single-phase-connected photovoltaic inverters (PVIs) in low-voltage distribution networks. A stochastic approach is used to calculate the harmonic voltage distortion with each customer in the network. The method has been applied to a 6-customer network for the connection of 2.5-kW single-phase PVIs with and without harmonic voltage background. From the results, it was observed that the contribution from 2.5 kW single-phase photovoltaic inverters to the individual harmonic distortion will not cause the established limits to be exceeded. Also, that the harmonic voltage background is often dominating and should be continuously observed.

  • 330.
    Schwanz, Daphne
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Möller, Friedemann
    Technische Universität Dresden.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Meyer, Jan Christian
    Technische Universität Dresden.
    Stochastic Assessment of Voltage Unbalance due to Single-Phase-Connected Solar Power2016Inngår i: 2016 17th International Conference on Harmonics and Quality of Power, Piscataway, NJ, 2016, s. 95-103, artikkel-id 7783353Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A stochastic method is presented in this paper to estimate the future voltage unbalance in a low-voltage distribution network with high-penetration of single-phase photovoltaic inverters (PVIs). Location and phase allocation of the PVIs are considered as input parameters for the stochastic simulation. The method has been applied to three different low-voltage networks: two in Sweden and one in Germany. In the Swedish networks, for 6-kW single-phase PVIs, it is likely that the contribution from single-phase photovoltaic inverters to the voltage unbalance exceeds 1%. The 2% value is unlikely to be exceeded. In the German network, for 4.6-kW single-phase PVIs the voltage unbalance is between 1.35% and 2.62%. The risk of high voltage unbalance can be reduced by a combination of controlled distribution over the phases and reduction of the maximum size for a single-phase PVI

  • 331.
    Schwanz, Daphne
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Möller, Friedemann
    Technische Universität Dresden.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Meyer, Jan
    Institute of Electrical Power Systems and High Voltage Engineering, Technische Universitaet Dresden, Technical University Dresden, Dresden University of Technology.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Stochastic Assessment of Voltage Unbalance due to Single-Phase-Connected Solar Power2017Inngår i: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 32, nr 2, s. 852-861, artikkel-id 7488998Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A stochastic method is presented in this paper to estimate the future voltage unbalance in a low-voltage distribution network with high-penetration of single-phase photovoltaic inverters (PVIs). Location and phase allocation of the PVIs are considered as input parameters for the stochastic simulation. The method has been applied to three different low-voltage networks: two in Sweden and one in Germany. In the Swedish networks, for 6-kW single-phase PVIs, it is likely that the contribution from single-phase photovoltaic inverters to the voltage unbalance exceeds 1%. The 2% value is unlikely to be exceeded. In the German network, for 4.6-kW single-phase PVIs the voltage unbalance is between 1.35% and 2.62%.The risk of high voltage unbalance can be reduced by a combination of controlled distribution over the phases and reduction of the maximum size for a single-phase PVI.

  • 332.
    Schwanz, Daphne
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Möller, Friedemann
    Technische Universität Dresden.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Meyer, Jan Christian
    Technische Universität Dresden.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Stochastic assessment of voltage unbalance due to single-phase-connected solar power2017Inngår i: 2017 IEEE PowerTech, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A stochastic method is presented in this paper to estimate the future voltage unbalance in a low-voltage distribution network with high-penetration of single-phase photovoltaic inverters (PVIs). The location and phase allocation of the PVIs are considered as input parameters for the stochastic simulation. The method has been applied to three different low-voltage networks: two in Sweden and one in Germany. In the Swedish networks, for 6-kW single-phase PVIs, it is likely that the contribution from single-phase photovoltaic inverters to the voltage unbalance exceeds 1%. The 2% value is unlikely to be exceeded. In the German network, for 4.6-kW single-phase PVIs, the voltage unbalance is between 1.35% and 2.62%. The risk of high-voltage unbalance can be reduced by a combination of controlled distribution over the phases and a reduction of the maximum size for a single-phase PVI.

  • 333.
    Schwanz, Daphne
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Hosting capacity for photovoltaic inverters considering voltage unbalance2017Inngår i: 2017 IEEE PowerTech, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2017, artikkel-id 7981274Konferansepaper (Fagfellevurdert)
    Abstract [en]

     In this paper the hosting capacity considering voltage unbalance is estimated for single-phase photovoltaic inverters (PVIs) in low-voltage distribution networks in Sweden. A stochastic approach is used to calculate the negative-sequence voltage unbalance for each of the possible locations in the network. The method has been applied to 6 and 28-customer networks for the connection of 6-kW single-phase PVIs. The impact of three-phase motors on the unbalance was also studied. From the results, it was observed that the contribution from single-phase photovoltaic inverters to the voltage unbalance likely exceeds 1%, but unlikely that it will reach 2% of voltage unbalance.

  • 334.
    Schwanz, Daphne
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Voltage unbalance due to single-phase photovoltaic inverters2017Inngår i: CIRED - Open Access Proceedings Journal, ISSN 2515-0855, Vol. 2017, nr 1, s. 906-910Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, the negative-sequence voltage unbalance is calculated for increasing numbers of single-phase photovoltaic inverters (PVIs) connected to low-voltage distribution networks. The transfer impedance matrix is used to calculate the negative-sequence voltage for each of the possible locations in the networks and a stochastic method is applied to estimate the voltage unbalance. The method has been applied to six- and 28-customer networks for the connection of 6 kW single-phase PVIs. Furthermore, the hosting capacity for each network has also been estimated. From the results, it was observed that it is likely that the contribution from single-phase PVIs to the voltage unbalance exceeds 1%, but unlikely that it will reach 2%.

  • 335.
    Sierra-Fernández, J.-M.
    et al.
    University of Cádiz, Algeciras, Spain.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    De La Rosa, J.-J.G
    University of Cádiz, Algeciras, Spain.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Palomares-Salas, J.-C.
    University of Cádiz, Algeciras, Spain.
    Application of spectral kurtosis to characterize amplitude variability in power systems' harmonics2019Inngår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 12, nr 1, artikkel-id en12010194Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The highly-changing concept of Power Quality (PQ) needs to be continuously reformulated due to the new schemas of the power grid or Smart Grid (SG). In general, the spectral content is characterized by their averaged or extreme values. However, new PQ events may consist of large variations in amplitude that occur in a short time or small variations in amplitude that take place continuously. Thus, the former second-order techniques are not suitable to monitor the dynamics of the power spectrum. In this work, a strategy based on Spectral Kurtosis (SK) is introduced to detect frequency components with a constant amplitude trend, which accounts for amplitude values' dispersion related to the mean value of that spectral component. SK has been proven to measure frequency components that follow a constant amplitude trend. Two practical real-life cases have been considered: Electric current time-series from an arc furnace and the power grid voltage supply. Both cases confirm that the more concentrated the amplitude values are around the mean value, the lower the SK values are. All this confirms SK as an effective tool for evaluating frequency components with a constant amplitude trend, being able to provide information beyond maximum variation around the mean value and giving a progressive index of value dispersion around the mean amplitude value, for each frequency component. 

  • 336.
    Singh, Gaurav
    et al.
    Department of Electrical and Computer Engineering, Clemson University.
    Collins Jr., Randolph
    Department of Electrical and Computer Engineering, Clemson University.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Larsson, Anders
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Impact of high frequency conducted voltage disturbances on LED driver circuits2017Inngår i: IEEE Power and Energy Society General Meeting, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Increasingly, consumer electronic devices utilize power supplies that have switching frequencies up to several tens of kilohertz. Consequently, emission in the frequency range 2 to 150kHz ('supraharmonics') is continuously increasing. Cases of conducted interference in LED lamps using switched mode power supplies, from supraharmonics have been reported over the past three years. This paper presents results from experiments where supraharmonic voltage distortion was applied to commercially available LED driver circuits. Variations of light output were obtained in some cases, along with evidence pointing to reduced converter efficiency and influence of point on wave of the distortion, on the light output. Importantly, it was shown that electromagnetic compatibility is not converter topology dependent, nor influenced by galvanic isolation. The results demonstrate that converters with similar topology can have vastly different behavior and there is a marked dissimilarity in performance among different topologies.

  • 337.
    Smith, Jeff W.
    et al.
    Distribution Planning, Operations and Studies, EPRI, Knoxville.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Meyer, Jan
    TU Dresden, Institute of Electrical Power Systems and High Voltage Engineering.
    Blanco, Ana Maria
    TU Dresden, Institute of Electrical Power Systems and High Voltage Engineering.
    Koo, Kah Leong
    National Grid, Power Quality and Modelling, System Design, Warwick.
    Mushamalirwa, Daudi
    GE Grid Solutions, Technical Institute - Network Consulting, Paris.
    Power quality aspects of solar power: Results from CIGRE JWG C4/C6.292017Inngår i: CIRED - Open Access Proceedings Journal, ISSN 2515-0855, Vol. 2017, nr 1, s. 809-813Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The increasing use of solar power connected to the public grid and the associated concern for deteriorating power quality triggered the formation of a joint working group with the aim to describe and quantify this impact. The WG formed in 2012 as a joint C4/C6 effort, formed to examine the power quality aspects of solar power, specifically addressing a number of phenomena, all which will be discussed in this study

  • 338.
    Song, Yuqian
    et al.
    Department of Electrical and Electronic Engineering, University of Hong Kong.
    Zhong, Jin
    Department of Electrical and Electronic Engineering, University of Hong Kong.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    An Optimal Long-Term Generation Expansion Plan considering CO2 Reduction Policies and Mechanisms2014Inngår i: The Renewable Energies and Power Quality Journal (RE&PQJ), ISSN 2172-038X, E-ISSN 2172-038X, nr 12, artikkel-id 306Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In a deregulated power system, a well-designed market mechanism could promote the optimal distribution of resources within the system. As one of the major sources of CO2 emissions, power industry can be seriously impacted by carbon emission-related policies and regulations. This paper considers three widely promoted emission policies, using a long-term power system planning model to obtain the optimal generation expansion plan for twenty years. By analysing and comparing system investment schemes under different emission-related mechanisms, the processes of how these policies influence generation investment are revealed. The effectiveness of these policies is compared to determine the optimal carbon emission mechanism.

  • 339.
    Speychal, M
    et al.
    STRI AB, Ludvika.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lindén, K
    STRI AB, Ludvika.
    Impact of increasing levels of DER on the dip frequency in transmission systems2006Inngår i: International Conference on Probabilistic Methods Applied to Power Systems, 2006: PMAPS 2006 ; 11 - 15 June 2006, [Stockhom, Sweden] / [IEEE, Institute of Electrical and Electronics Engineers], Piscataway, NJ: IEEE Communications Society, 2006Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper describes a study to estimate the increase in voltage-dip frequency when an increasing amount of large power stations is replaced by small units connected to distribution systems

  • 340.
    Ström, Lars
    et al.
    Energy Markets Inspectorate.
    Bollen, Math
    Kolessar, Rémy
    Energy Markets Inspectorate.
    Voltage quality regulation in Sweden2011Inngår i: Proceedings of CIRED 21st International Conference on Electricity Distribution, 2011, artikkel-id 0168Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents the voltage-quality requirements set by the Swedish energy regulator. Requirements have been set for harmonics, unbalance, slow voltage variations, voltage dips, voltage swells and rapid voltage changes, which are all discussed in this paper. This paper further discusses recommended measurement methods for verification of compliance with the requirements and the way in which voltage-quality regulation takes place in practice.

  • 341. Sun, Y
    et al.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Ault, G
    Improving distribution system reliability by means of distributed generation2007Inngår i: Conference proceedings: 19th International Conference and Exhibition on Electricity Distribution : Vienna, 21 - 24 May 2007, Liege: AIM , 2007Konferansepaper (Fagfellevurdert)
  • 342. Sun, Y
    et al.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Ault, G
    Issues for reliability analysis of islanded microgrids with distributed generation and energy storage2007Inngår i: Conference proceedings: 19th International Conference and Exhibition on Electricity Distribution : Vienna, 21 - 24 May 2007, Liege: AIM , 2007Konferansepaper (Fagfellevurdert)
  • 343.
    Sun, Y
    et al.
    Institute for Energy and Environment, University of Strathclyde, Glasgow.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Ault, G.W
    Institute for Energy and Environment, University of Strathclyde, Glasgow.
    Probabilistic reliability evaluation for distribution systems with DER and microgrids2006Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents a method for calculating the reliability of distribution systems with distributed energy resources (DER). The impact of intentional islanding of the DER units on the reliability is studied in detail as well as the impact of different switching devices. A Monte-Carlo-based computer program has been developed to simulate the performance of different typical distribution feeders. Details of the Monte-Carlo simulation and selected simulation results are given in the paper. The presence of circuit breakers and the reliability of the DER unit have a large influence on the supply reliability. The reduction in interruption costs is further determined by the relation between costs and duration.

  • 344.
    Sutaria, Jil
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Ahmed, Kazi Main Uddin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Propagation of Supraharmonics through EMI Filters with Varying Loads2019Konferansepaper (Fagfellevurdert)
  • 345.
    Tang, Yuchen
    et al.
    Department of Electrical and Electronic Engineering, University of Hong Kong.
    Zhong, Jin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Aggregated optimal charging and V2G control for electric vehicles under large EV population2016Inngår i: IET Generation, Transmission & Distribution, ISSN 1751-8687, E-ISSN 1751-8695, Vol. 10, nr 8, s. 2012-2018Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Effective charging and vehicle-to-grid (V2G) control strategies can utilise the properties of electric vehicles (EVs) to obtain various benefits. EVs are modelled as individuals in existing charging control algorithms. In this study, a new modelling method of EVs and an optimal charging control strategy are proposed so that all EVs in a control area can be regarded as a single object in the optimisation process. The strategy minimises the total charging cost of EVs, and can be further expanded to serve V2G control. With the new modelling method, the computational burden of the optimisation algorithm can be reduced significantly and does not increase with the number of EVs. Thus the strategy is extremely effective when the number of EVs becomes large, and the implementation cost could be more reasonable since less computational capacity is required. Case studies are presented to illustrate the performance of the strategy.

  • 346.
    Tang, Yuchen
    et al.
    Department of Electrical and Electronic Engineering, The University of Hong Kong.
    Zhong, Jin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Schedule of air-conditioning systems with thermal energy storage considering wind power forecast errors2018Inngår i: International Journal of Electrical Power & Energy Systems, ISSN 0142-0615, E-ISSN 1879-3517, Vol. 95, s. 592-600Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    As the penetration of uncontrollable renewable energy sources (RESs) increases, energy storage and flexible demand will play a more important role in future power systems. In this paper, air-conditioning systems with thermal energy storage (A/C storage systems) are studied as a way of compensating uncertainties from wind power. Wind power forecast errors are analyzed from different perspectives in order to better assist the schedule of storage devices. An operation scheme is proposed for A/C storage systems for both day-ahead scheduling and real-time operation, based on the features of wind power forecast errors. The targets include load management and compensation of wind power forecast errors. Simulations illustrate the effectiveness of the proposed scheme to support power systems with high wind penetration.

  • 347.
    Tjäder, Anna
    et al.
    AT Power, 43539 Mölnlycke.
    Gu, Irene
    Chalmers University of Technology, Department of Signals and Systems.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Performance evaluation for frequency estimation of transients using the ESPRIT: measured noise versus white noise2008Inngår 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]

    A number of papers have proposed to use the ESPRIT method for estimating some power system transients. The mathematical model for using the ESPRIT requires that the additive noise be white. Fail to satisfy this could lead to degraded performance of frequency estimation. However, in practical situations the noise is often non-white. In this paper we study the performance of the ESPRIT frequency estimation method when the additive noise is measured from power systems. It is shown that tests using synthetic white noise are not sufficient for realistic power-system scenarios, as the noise is often non-white and not i.i.d. distributed. First, a set of measured voltage waveforms is superimposed to synthetic transients with known frequencies. This yields a set of semi-measured transients. The ESPRIT method is then applied to estimate the frequencies. The performance of the ESPRIT is then evaluated in term of the mean value and standard deviation. Our experiments show that, for a transient contains one sinusoid, the ESPRIT of sinusoidal model order K=2 results in an acceptable accuracy if the amplitude of the transient is well above the noise level and the transient frequency is not too close to the powersystem frequency. This is sufficient for most practical applications. A better performance for higher noise levels is obtained by significantly increasing the sinusoidal model order in the ESPRIT.

  • 348.
    Torstensson, Daniel
    et al.
    Energy Markets Inspectorate.
    Bollen, Math
    Kolessar, Rémy
    Energy Markets Inspectorate.
    The Swedish benchmarking report on continuity of supply2011Inngår i: Proceedings of CIRED 21st International Conference on Electricity Distribution, 2011, artikkel-id 0233Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents the results of the annual evaluation of the reliability in local electricity networks in Sweden. A distinction is made in SAIFI and SAIDI for rural, suburban and urban networks. The values are significantly higher for rural than for urban networks; also the spread between network operators is higher for rural networks. Data is also presented on the number of very-long interruptions and on the investment and running costs by the network operators. Whereas the running costs remain constant, the investments have increased almost three-fold since 2004.

  • 349. Vailati, R
    et al.
    Brekke, K
    Evans, G
    Friedl, W
    Schotman, H
    Steiner, M
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Kapetanovic, T
    Villa, F
    European energy regulators’ views on regulating smarter transmission networks2012Konferansepaper (Fagfellevurdert)
  • 350. Vailatia, R
    et al.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Esteves, J
    Evans, G
    Friedl, W
    A status review of regulatory approaches to smart electricity networks across Europe2013Konferansepaper (Annet vitenskapelig)
45678 301 - 350 of 386
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