| 1. |
- Andersson, Marcus, et al.
(författare)
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Interfering signals and attenuation potential problems with communication via the power grid
- 2006
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Ingår i: Proceedings of Nordic Distribution and Asset Management Conference : NORDAC 2006.
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Annan publikation (populärvet., debatt m.m.)abstract
- 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.
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| 2. |
- Bollen, Math, et al.
(författare)
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Harmonic emission from installations with energy-efficient lighting
- 2011
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Ingår i: Proceeding of the International Conference on Electrical Power Quality and Utilisation, EPQU. - Piscataway, NJ : IEEE. - 978-146730379-8 ; 797-802
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Annan publikation (populärvet., debatt m.m.)abstract
- 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
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| 3. |
- Bollen, Math, et al.
(författare)
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Limits for voltage distortion in the frequency range 2 to 9 kHz
- 2008
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Ingår i: I E E E Transactions on Power Delivery. - I E E E. - 0885-8977. ; 23:3
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Tidskriftsartikel (övrigt vetenskapligt)abstract
- This paper addresses voltage distortion in the frequency range 2 to 9 kHz, above what is normally considered in harmonic studies. By extrapolating the voltage-distortion limits that exist in international standards for distortion up to 2 kHz, it is concluded that 0.5% of nominal voltage per 200-Hz band is a safe limit. This limit is next used to estimate the number of small generator units (1-10 kW) that can be connected to a low-voltage grid. It is concluded that in some cases the connection of one or just a few units already leads to a distortion level above the limit.
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| 4. |
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| 5. |
- Gil-de-Castro, A., et al.
(författare)
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LED street lighting a power quality comparison among street light technologies
- 2013
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Ingår i: Lighting Research and Technology. - Sage Science Press (UK). - 1477-1535.
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Tidskriftsartikel (övrigt vetenskapligt)abstract
- High-pressure sodium lamps are currently the main lamps used in public lighting. However, the possibility of using high-power light emitting diode (LEDs) for street lighting is growing continuously due to their greater energy efficiency, robustness, long life and light control. The aim of this paper is to study the power quality of high-power lighting networks based on LED and high-pressure sodium lamps. Both electromagnetic and dimmable electronic ballasts, which can dim the lamp output smoothly and uniformly, have been used connected to high-pressure sodium lamps. High-pressure sodium lamps connected to electronic equipment have been tested with different arc power levels using dimming on a 230 V power supply. The study presented in this paper is completely based on measurements, including harmonic currents in the frequency range up to 150 kHz for all the technologies. The main results show a broadband spectrum in LED lamps which confirms other research in fluorescent lamps powered by high-frequency ballasts. Results also indicate a decrease in the harmonic value with increasing harmonic order, and a decrease in the harmonic value at half load (60%) compared with full load (100%). Although total harmonic distortion of the current is lower with high-pressure sodium lamps connected to electronic rather than electromagnetic ballasts, LED lamps achieved the lowest total harmonic distortion of curren
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| 6. |
- Lundmark, Martin, et al.
(författare)
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EMC filter common mode resonance
- 2009
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Ingår i: 2009 IEEE Bucharest PowerTech : Bucharest, Romania, 28 June - 2 July 2009. - Piscataway, NJ : IEEE. - 978-1-424-42234-0 ; 2312-2317
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Annan publikation (populärvet., debatt m.m.)abstract
- 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.
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| 7. |
- Lundmark, Martin, et al.
(författare)
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Harmonics and high-frequency emission by small end-user equipment
- 2006
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Ingår i: International Conference on Harmonics and Quality of Power. ; :12
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Konferensbidrag (övrigt vetenskapligt)abstract
- This paper discusses different treatments of harmonics in three phase systems, especially passive and active power factor correction (PFC). The change from harmonics below 2 kHz to above 2 kHz is described. Measurements have been carried out with two types of computer load together with LCD and florescent light driven by electronic ballast: on a large number of devices during a LAN party and on individual devices in the laboratory. Also some aspects of increasing numbers of equipment are illustrated.
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| 8. |
- Lundmark, Martin, et al.
(författare)
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High-frequency components in the neutral and protective earth currents due to electronic equipment
- 2007
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Ingår i: Conference proceedings : 19th International Conference and Exhibition on Electricity Distribution : Vienna, 21 - 24 May 2007. - Liege : AIM.
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Annan publikation (populärvet., debatt m.m.)abstract
- This paper addresses the issue of neutral and protective earth currents in the frequency range 2 through 150 kHz. Both theoretical analysis and measurements will be presented. It is concluded that a large part of the high frequency distortion in the phase currents closes via the neutral wire and impacts the terminal voltage for equipment in the other phases. The introduction of HF-harmonics is even more detrimental to the intention with three-phase systems to minimize the currents outside the phase conductors.
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| 9. |
- Lundmark, Martin, et al.
(författare)
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Increased levels of electrical fields in buildings
- 2002
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Ingår i: Biological effects of EMFs : proceedings, Rhodes, Greece, 7 - 11 October 2002 : [International Workshop on Biological Effects of Electromagnetic Fields]. - Rhodes : University of Ioannina. - 960-867333-X
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Annan publikation (populärvet., debatt m.m.)abstract
- In order to save energy and improve the performance, various electrical apparatus are equipped with power electronics. Normally power electronic equipment produce harmonics and high frequency noise. To handle noise emission, power electronic equipment uses EMC filters and are tested according to EMC standards. But the question is whether these tests are enough to avoid noise emissions in buildings? It has been shown, that electrical equipment distributes electrical fields inside a building using the PE wire. In order to avoid or limit electrical field it is necessary to find the sources and stop the distribution. The levels of electrical fields in the frequency range between 10 kHz and 30 MHz in office buildings and homes are rather unknown. One reason is lack of civil standards, another is lack of and difficulties in measurements. In this paper results from measurements of electrical fields in the frequency range between 10 kHz and 30 MHz at different locations is shown. An interesting result from these measurements is that the level of the electrical fields from a HF-fittings are approximately 10 times the level from video display units (VDU). This paper also shows a method to analyze sources of electrical fields.
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| 10. |
- Lundmark, Martin, et al.
(författare)
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Required changes in emission standards for high-frequency noise in power systems
- 2006
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Ingår i: International Journal of Energy Technology and Policy. - Inderscience Publishers. - 1472-8923. ; 4:1-2
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Tidskriftsartikel (övrigt vetenskapligt)abstract
- This paper discusses some recent developments that make the existing standards on the emission of high-frequency noise in power systems need to be reconsidered. It is shown that it is possible for an equipment to remain below the emission limits while at the same time the disturbance level increases beyond what was intended by the standard document. Further, the change from analog to digital communication and the use of communication via the power system, make that the permitted disturbance levels need to be reconsidered. This paper also contains an example of measured high-frequency noise and proposes a framework for re-coordination of emission and immunity levels.
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