| 1. |
- 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. - Rhodes : University of Ioannina. - 960867333X
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Konferensbidrag (refereegranskat)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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| 2. |
- Lundmark, Martin, et al.
(författare)
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The use of protective earth as a distributor of fields and radiation
- 2000
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Ingår i: Biological effects of EMFs. - Heraklio : Workshop on Biological Effects of Electromagnetic Fields. - 9608673305
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Konferensbidrag (refereegranskat)abstract
- Apart from being a safety arrangement, the protective earth, PE, is also defined as an equipotential plane which serves as a reference voltage for a circuit. Interest in the PE for EMC reasons is focused on an equipotential point. Still, most PE installation on site is carried out as a safety arrangement. In order to fulfill EMC standards regarding low emission, equipment is shielded and the shield is connected to the PE wire.The purpose of this paper is to show that electrical equipment distributes its electrical fields using the PE wire. Measurements have been taken on light fittings.
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| 3. |
- 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.
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Konferensbidrag (refereegranskat)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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| 4. |
- 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 Communications Society. - 9781467303798 ; , s. 797-802
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Konferensbidrag (refereegranskat)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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| 5. |
- 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: IEEE Transactions on Power Delivery. - 0885-8977 .- 1937-4208. ; 23:3, s. 1481-1487
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Tidskriftsartikel (refereegranskat)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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| 6. |
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| 7. |
- Bollen, Math, et al.
(författare)
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Standards for supraharmonics (2 to 150 kHz)
- 2014
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Ingår i: IEEE Electromagnetic Compatibility Magazine. - 2162-2264. ; 3:1, s. 114-119
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Tidskriftsartikel (refereegranskat)abstract
- There is a serious interest from the international standard-setting community in knowledge about voltage and current distortion in the frequency range 2 to 150 kHz, referred to as supraharmonics. At the same time, research is ongoing at a number of locations, but the knowledge about supraharmonics remains limited. This paper compares some of the properties of harmonics and supraharmonics. An increase in supraharmonics for individual devices is observed in association with a decrease in harmonic emission (i.e. below 2 kHz). A proposal is made for setting limits in this frequency range. The proposal is based on existing standards and is meant to be for discussion. The authors strongly encourage an open discussion about the proposed limits. There are a number of differences between harmonics and supraharmonics that are not covered by the proposed set of limits. A substantial amount of further research is needed to extend the standard framework for supraharmonics such that this can be covered by standards
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| 8. |
- Larsson, Anders, et al.
(författare)
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Distortion of fluorescent lamps in the frequency range 2-150 kHz
- 2006
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Konferensbidrag (refereegranskat)abstract
- This paper presents measurements of voltages and currents taken by fluorescent lamps with high-frequency ballast. The results are discussed in time domain, in frequency domain and in time-frequency domain. A number of different high-frequency components are present: recurrent transients, narrow-band time-invariant signals, and time-dependent signals. The increase in distortion with increasing number of lamps is studied as well. The distortion increases about linear with the number of lamps in the frequency range 2-9 kHz but shows only a minor increase or no increase at all in the frequency range 9-150 kHz.
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| 9. |
- Larsson, Anders, et al.
(författare)
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Evolution of the harmonic distortion from state-of-the-art computers : 2002 to 2008
- 2009
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Ingår i: CIRED 20th International Conference on Electricity Distribution. - Red Hook, NY : Curran Associates, Inc.. - 9781615675227 ; , s. 164-167
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 10. |
- Larsson, Anders, et al.
(författare)
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Measurement and analysis of high-frequency conducted disturbances
- 2007
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Ingår i: Conference proceedings. - Liege : AIM.
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Konferensbidrag (refereegranskat)abstract
- The frequency range above the "traditional" harmonic range up to about 2 to 3 kHz has been under investigation for a while but less attention has been paid to the frequency range slightly above. This paper presents measurements both in laboratory environment and in the field on different types of equipment and general long- term measurement on site in the low voltage network. The general aim of this paper is to increase the knowledge about voltage and current distortion in the frequency range above 2 kHz.
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