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  • 1.
    Andersson, Marcus
    et al.
    Luleå tekniska universitet.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lundmark, Martin
    Larsson, Anders
    Wahlberg, Mats
    Bollen, Math
    Interfering signals and attenuation: potential problems with communication via the power grid2006Inngår i: Proceedings of Nordic Distribution and Asset Management Conference: NORDAC 2006, 2006Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper will give a general overview of the potential problems associated with remote-meter reading via the power grid and describe some of the technologies available. A comparison will be made between the power grid as a communication channel and other, dedicated and shared, channels. Examples will be given of practical cases in which the communication channel does not function in the intended way.

  • 2.
    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.

  • 3.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Larsson, Anders
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lundmark, Martin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Harmonic emission from installations with energy-efficient lighting2011Inngår i: Proceeding of the International Conference on Electrical Power Quality and Utilisation, EPQU, Piscataway, NJ: IEEE Communications Society, 2011, s. 797-802Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents the results from a number of measurements of the harmonic emission from installations that contain a large number of energy-efficient lamps. Two of the measurements concern the replacement of incandescent lamps with CFL and LED; the other measurement concerns an installation with up to 48 fluorescent lamps with high-frequency ballasts. The paper also contains a discussion on why the (total) power factor is not a good measure to quantify the performance of lamps or installations containing large numbers of lamps

  • 4.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Laboratory and field measurements of the power factor and the harmonic emission from energy-efficient lamps2011Konferansepaper (Fagfellevurdert)
  • 5.
    Bollen, Math
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Yao, Liangzhong
    Areva T and D, Technology Centre, Stafford.
    Rönnberg, Sarah
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Harmonic and interharmonic distortion due to a windpark2010Inngår i: IEEE Power and Energy Society General Meeting, Piscataway, NJ: IEEE Communications Society, 2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper discusses two aspects of the impact of windparks on the waveform distortion in the power system: emission and resonances. The paper gives a general overview of the emission and shows measurement results from a small but modern windpark connected to a 10-kV feeder and estimates the need for network strength to limit the resulting voltage distortion. The paper also gives a general overview of harmonic resonances associated with windparks and illustrates this by means of two numerical examples. Important conclusions from this paper are than harmonic resonances are more likely to be a concern that the emission from windparks, and that the interharmonic emission and the emission at non-characteristic harmonics are more prominent than with existing installations.

  • 6.
    Gil-de-Castro, Aurora
    et al.
    Departamento A.C., Electrónica y T.E. Escuela Politécnica Superior, University of Cordoba.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Moreno-Munoz, Antonio
    Departamento A.C., Electrónica y T.E. Escuela Politécnica Superior, University of Cordoba.
    Emission on the low voltage grid: measurements in an urban area2014Inngår i: The Renewable Energies and Power Quality Journal (RE&PQJ), ISSN 2172-038X, E-ISSN 2172-038X, nr 12, artikkel-id 472Artikkel i tidsskrift (Fagfellevurdert)
  • 7.
    Larsson, Anders
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Lundmark, Martin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Measurements of high-frequency (2-150 kHz) distortion in low-voltage networks2010Inngår i: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 25, nr 3, s. 1749-1757Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents different methods to describe voltage and current distortion in the frequency range 2 to 150kHz. The time-frequency domain was shown to give additional information next to the time- and frequency-domain representations. Measurements of different devices and at different locations showed remnants of the switching frequency of the power electronics as well as lower frequency oscillations around the current zero crossing to be present in voltage and current. The voltage distortion is shown to vary a lot during the day and between locations.

  • 8.
    Larsson, Anders
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Gil-de-Castro, Aurora
    University of Cordoba.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Field and laboratory measurements of interference with light equipment due to waveform distortion originating from a large rectifier2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper will present a case study where light in anoffice building is disturbed and do not function properly.From measurements it is shown that a UPS system iscausing distortions. One lamp from the office wasbrought to laboratory where the distortions was repeatedand subjected to the lamp. When doing so the lampshowed the same immunity problem.

  • 9.
    Larsson, Anders
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lundmark, Martin
    Bollen, Math
    Wahlberg, Mats
    Rönnberg, Sarah
    Evolution of the harmonic distortion from state-of-the-art computers: 2002 to 20082009Inngår i: CIRED 20th International Conference on Electricity Distribution: 8 -11 June 2009, Prague Congress Centre, Prague, Red Hook, NY: Curran Associates, Inc., 2009, s. 164-167Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper shows trends in harmonic emission by large groups of modern computers over a 7-year period. The measurements were obtained at computer tournaments where almost exclusively the newest types of computers are used. The measurements clearly show that the harmonic distortion is decreasing significantly while the power consumption per computer does not change significantly.

  • 10.
    Larsson, Anders
    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.
    Reduced life-time of lamps: Temperature rise and bad power quality2014Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To save energy, many new buildings have modern energy saving lighting installed. In large department or grocery stores the use of fluorescent lamps powered by high frequency electronic ballast is common. There are however consistent reports of large numbers of failures of the electronic ballast of these lamps. The failures of the electronic ballast are due to high temperature or bad power quality. But neither of these reasons has been confirmed as the cause. This paper discusses in general the lifetime of electronic ballast. The paper also presents detailed analysis of results from measurement performed in a grocery store where high instances of failure have been observed. Both temperature and power quality in the harmonic range and 2 to 150 kHz have been included in the measurements

  • 11.
    Larsson, Anders
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Lundmark, Martin
    Waveform distortion at computer festivals: 2002 to 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 shows measurements of the harmonic emission by large groups of state-of-the-art computers measured at five different occasions from 2002 to 2008. The emission was measured during LAN-festivals where the participants use mainly the newest models of computer. This allows insight in the change in emission of computers during the last 6 years. The results from these measurements show that the distortion level generated by computers is decreasing while the power consumption does not show any significant change.

  • 12.
    Lundmark, Martin
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Wahlberg, Mats
    Larsson, Anders
    Bollen, Math
    EMC filter common mode resonance2009Inngår i: 2009 IEEE Bucharest PowerTech: Bucharest, Romania, 28 June - 2 July 2009 / [ed] Lucian Toma, Piscataway, NJ: IEEE Communications Society, 2009, s. 2312-2317Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper discusses the possibility that high common mode voltages occur in low-voltage distribution due to oscillations between parallel connected EMC-filters. It is shown that such oscillations may occur in the frequency range between 2 kHz to 150 kHz. Simulations and measurements have been carried out with different types of parallel connected power inlet filter, a common EMC Filter, and the circumstances giving oscillations have been highlighted.

  • 13.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Larsson, Anders
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Emission from different types of energy efficient lamps at frequencies up to 150 kHz2012Konferansepaper (Fagfellevurdert)
  • 14.
    Rönnberg, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Wahlberg, Mats
    Power quality issues due to electronic lighting2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    With the interest to reduce electrical energy consumption there is an upcoming shift from the traditional incandescent lamps to more energy efficient types of lighting. This has raised a concern of a possible adverse effect on the power grid as we replace a resistive load with an electronic one. The main concerns include harmonic distortion, losses in the grid, and displacement power factor (cos ). A set of measurements have been made in order to determent how a shift in lamps would affect a number of power quality parameters. The measurements have been conducted on a typical household base load consisting of a mix of lamps, TV, computers, heat and kitchen equipment. The measurements have been performed in the laboratory so as to have complete control over the load. A typical consumption pattern has been defined however so as to make the measurements both realistic and reproducible. In the initial stage the installation contains only incandescent lamps; in the final stage all incandescent lamps are replaced with a more energy efficient alternative. A second set of measurements have been made in a medium size hotel, with a load of over 500 incandescent lamps. The power quality has been monitored before, during and after all the lamps were replaced by 40 W equivalent LED lamps. This paper will focus on harmonic distortion up to 9 kHz as well as the affect a shift in lamps will have on the displacement power factor and on losses in the distribution grid.

  • 15.
    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.

  • 16.
    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.

  • 17.
    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

  • 18.
    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.

  • 19.
    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.

  • 20.
    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.

  • 21.
    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.

  • 22.
    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.

  • 23.
    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)
  • 24.
    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))
  • 25.
    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.

  • 26.
    Wahlberg, Mats
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Case study on electrical conductivity in wood poles2017Rapport (Annet vitenskapelig)
  • 27.
    Wahlberg, Mats
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Currents in power line wood poles2011Inngår i: Proceedings of CIRED 21st International Conference on Electricity Distribution, 2011, artikkel-id 0347Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Over the last few years some rather severe problems have arisen for poles used to support overhead power lines. A wooden power line pole is assumed to be a good electric insulator because of the basic properties of wood with its porous structure and cellulose compounds forming the major part of the cell walls. A fault during which an insulator is broken or a phase conductor has loosened, normally poses no danger. In rare cases a fire has started, but this has not been seen as a sufficiently dangerous situation to change maintenance practice. However, it has been noticed that under certain circumstances such poles can get conductive enough to result in hazardous or even lethal current for power line maintenance workers climbing the pole.

  • 28.
    Wahlberg, Mats
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Currents in power line wood poles: a measuring method2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Recently a maintenance worker in Sweden was killed when climbing into a wood pole supporting an 11-kV overhead line. The investigating done afterwards raised the suspicion that a current flowed through the pole was sufficient to kill a person. Due to a broken insulator one of the phases of the 11-kV line had been resting on the metal crossbar. This accident triggered an investigation in order to determine if power line wood poles can conduct current and if so, whether this current can be sufficient to injure a maintenance worker climbing into the pole. The study has been made at the 11 kV level on a pole while a live wire was resting on the metal cross arm as would be the case if the insulator had broken. A proposal for a measuring method has been developed in order to determine under what conditions climbing should be prohibited. In Sweden the use of wood poles as part of 11 kV overhead lines is fairly common. A three phase system is used to distribute 11 kV, one wire for each phase, and the three wires are supported by insulators mounted on a horizontal metal (or wood) cross arm. The poles are treated with some kind of preservative to protect the wood from rot and insects. Three kinds of preservatives are commonly used in Sweden: arsenic, creosote and salt. In this study eight poles with different preservative and age varying from 50 years old to brand new have been examined in a realistic environment. The measurements presented in this paper support the earlier suspicion that a wood pole used for distributing power can conduct current if a fault occurs and a live wire comes in contact with the metal cross arm. It also shows that the current through a parallel, not connected to earth, resistor (i.e. a human climbing the pole) can reach potentially harmful amplitudes. Three main variables that affect the electrical characteristics of the pole have been identified: the preservation of the wood; the environmental temperature; and the humidity of the surroundings. There are however other variables that can have an impact on the conductivity of the pole for example how the pole was dried before preservation.

  • 29.
    Wahlberg, Mats
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Design of power lines poles that will be safe even when a phase has come in contact with crossarm.2014Konferansepaper (Fagfellevurdert)
  • 30.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Larsson, Anders
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    A statistic study of harmonics and interharmonics at a modern wind-turbine2014Inngår i: International Conference on Harmonics and Quality of Power. Proceedings: , s. 718-722, artikkel-id 6842921Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

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

  • 31.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Larsson, Anders
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Measurements of harmonic emission versus active power from wind turbines2014Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, nr 108, s. 304-314Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

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

  • 32.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    A comparison study of harmonic emission measurements in four windparks2011Inngår i: 2011 IEEE Power and Energy Society General Meeting, Piscataway, NJ: IEEE Communications Society, 2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

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

  • 33.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Characteristic and non-characteristic harmonics from windparks2011Inngår i: Proceedings of CIRED 21st International Conference on Electricity Distribution, CIRED - Congrès International des Réseaux Electriques de Distribution, 2011, artikkel-id 0251Konferansepaper (Fagfellevurdert)
    Abstract [en]

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

  • 34.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Comparison of harmonic emissions at two nodes in a windpark2012Inngår i: 15th IEEE International Conference on Harmonics and Quality of Power (ICHQP 2012), IEEE Communications Society, 2012, s. 313-319Konferansepaper (Fagfellevurdert)
    Abstract [en]

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

  • 35.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Measurements at two different nodes of a windpark2012Inngår i: 2012 IEEE Power and Energy Society General Meeting, Piscataway, NJ: IEEE Communications Society, 2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

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

  • 36.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Measurements of four-windpark harmonic emissions in northern Sweden2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

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

  • 37.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wind power harmonic emission versus active-power production2014Konferansepaper (Fagfellevurdert)
  • 38.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Cundeva, S
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Harmonic emission study of individual wind turbines and a wind park2013Inngår i: The Renewable Energies and Power Quality Journal (RE&PQJ), ISSN 2172-038X, E-ISSN 2172-038X, nr 11Artikkel i tidsskrift (Fagfellevurdert)
  • 39.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Cundeva, S.
    University Sts. Cyrill and Methodias, Skopje, Institute of Electroheat Faculty of Electrical Engineering and Information Technology.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Measurements of harmonic and interharmonic emission from wind power systems2014Inngår i: Russian Electrical Engineering, ISSN 1068-3712, Vol. 85, nr 12, s. 769-776Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

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

  • 40.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Cundeva, Snezana
    Institute of Electroheat Faculty of Electrical Engineering and Information Technology.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Harmonic aspects of wind-power installations2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

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

1 - 40 of 40
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