WO1994026084A1 - Procede et dispositif servant a amortir activement des champs magnetiques de frequence industrielle - Google Patents

Procede et dispositif servant a amortir activement des champs magnetiques de frequence industrielle Download PDF

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Publication number
WO1994026084A1
WO1994026084A1 PCT/SE1994/000280 SE9400280W WO9426084A1 WO 1994026084 A1 WO1994026084 A1 WO 1994026084A1 SE 9400280 W SE9400280 W SE 9400280W WO 9426084 A1 WO9426084 A1 WO 9426084A1
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WO
WIPO (PCT)
Prior art keywords
field
magnetic
current
station
magnetic fields
Prior art date
Application number
PCT/SE1994/000280
Other languages
English (en)
Inventor
Sven HÖRNFELDT
Original Assignee
Asea Brown Boveri Ab
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Asea Brown Boveri Ab filed Critical Asea Brown Boveri Ab
Publication of WO1994026084A1 publication Critical patent/WO1994026084A1/fr

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02B—BOARDS, SUBSTATIONS OR SWITCHING ARRANGEMENTS FOR THE SUPPLY OR DISTRIBUTION OF ELECTRIC POWER
    • H02B7/00—Enclosed substations, e.g. compact substations
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02B—BOARDS, SUBSTATIONS OR SWITCHING ARRANGEMENTS FOR THE SUPPLY OR DISTRIBUTION OF ELECTRIC POWER
    • H02B5/00—Non-enclosed substations; Substations with enclosed and non-enclosed equipment
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02B—BOARDS, SUBSTATIONS OR SWITCHING ARRANGEMENTS FOR THE SUPPLY OR DISTRIBUTION OF ELECTRIC POWER
    • H02B7/00—Enclosed substations, e.g. compact substations
    • H02B7/06—Distribution substations, e.g. for urban network

Definitions

  • a method and a device for actively damping power-frequency magnetic fields are described.
  • the present invention relates to a method and a device for active damping of the power-frequency magnetic fields which occur in the vicinity of, for example, small transformer, network and distribution stations. These stations are often designed as substations of sheet metal or concrete.
  • the magnetic fields which are generated at these substations may pose a health hazard to persons residing or acting in the vicinity of these substations.
  • the magnetic fields can also disturb sensitive electronics, visual display units, etc.
  • the above-mentioned stations are located in the basement of large buildings which may house both work ⁇ shops, offices, and dwelling spaces.
  • magnetic fields of up to several tens of microtesla have been measured. These are magnetic fields which may clearly affect electronic equipment and which may also constitute a health hazard to persons living or permanently working in this environment. Studies on this are described, inter alia, in "Occupational exposure to electromagnetic fields in relation to leukemia and brain tumours. A case-study", published as a PM edition by the National Institute of Occupational Health, Solna, Sweden, written by B.
  • the screening effect arises substantially by the magnetic field being closed by the magnetic screen.
  • the screening is performed with a non-magnetic material, for example aluminium in the form of a plate
  • eddy currents will be induced in the plate, which gives rise to magnetic fluxes.
  • Cooperation between the magnetic flux from the magnetic field source and the flux generated by the eddy currents results in a weakened flux on that side of the aluminium plate which faces outwards from the source.
  • the field weakening becomes more effective the lower the resistivity of the plate, that is, it is desirable to have a large and thick plate with a high electrical conductivity.
  • Magnetic screening is desirable also within other fields than the power-frequency field.
  • Ships of various kinds because of their own static magnetic fields or magnetic fields slowly varying in time, may trace or trigger magnetic mines.
  • Various attempts are therefore made to screen the ships such that they cannot be detected by means of magnetic-field-sensing probes, and such that they do not activate magnetic mines in the vicinity of the ship. Methods for such screening are described, inter alia, in the patents DE 3614527 C2, "Verfahren Kunststoff Erstein ein für magnetischen
  • the present invention relates to a method and a device for actively damping the power-frequency magne ⁇ tic fields which arise in the vicinity of small-sized trans- former, network and distribution substations.
  • the invention is most justified when such a substation is located in the basement of large buildings where otherwise sensitive elec ⁇ tric equipment is used and where people reside frequently and for a long time in the storeys above the basement.
  • the invention comprises generating a field directed opposite to the non-desired magnetic field from the electric equipment in the substation. This is done in such a way that a compen ⁇ sating coil is placed along the walls of the substation.
  • a magnetic-field-sensing probe is placed under the roof of the substation in such a way that it covers a region where the amplitude of the magnetic field is as close to the mean field over the entire roof as possible.
  • the magnetic-field-sensing probe is then connected to a current amplifier which, in turn, feeds the compensating coil such that the amplitude of the field at the probe is considerably reduced.
  • Figure 1 shows an exploded view of part of a basement in which is located a distribution substation with a transformer room and a distribution room for associated switchgear.
  • Figure 2 shows a device for damping the power-frequency mag ⁇ netic fields which occur in the vicinity of such stations.
  • Figure 1 shows how a transformer 1 is located in a separate transformer room 2 and how switchgear 3 is located in a distribution room 4.
  • the transformer and the switchgear are interconnected through the connection cubicle 5 of the transformer by means of a busbar or cable (not shown) .
  • the interconnection preferably takes place with cables disposed in cable channels in the floor of the station.
  • Figure 2 shows only the separate transformer room 2 with walls, floor and roof.
  • a magnetic- field-sensing probe 6 is placed under the roof 7 of the transformer room.
  • a compensating coil 8 is arranged around the walls of the transformer room.
  • the object of the device is to generate a field directed opposite to the magnetic field sensed by the probe.
  • the electric signal from the probe which corresponds to the value of the magnetic field in question, is led to a current amplifier 9 which, in conventional manner, is adapted to supply the compensating coil with such a current, both with respect to amplitude and phase, that the magnetic field measured by the probe is considerably reduced.
  • Such stations are sometimes located in the upper storey of a building.
  • the screening will then be needed in relation to the storeys below the station.
  • the probe has to be placed in the floor of the station and the compensating coil has to be placed around the walls in the vicinity of the floor.
  • the space which is to be screened may be in the same plane as the station.
  • the probe has to be placed in the wall of the station which faces an adja ⁇ cent room and the compensating coil has to be placed such that the screening becomes effective in relation to the space in question.
  • an adaptation has to be made of the turns of the compensating winding and the delivered current of the current amplifier, such that the generated field becomes sufficient to be able to compensate for the undesired magnetic field.
  • a magnetic-field- sensing probe which has such a coverage that it reproduces a magnetic field which, as closely as possible, gives a value corresponding to the mean field over the whole roof.
  • a number of separate compensating coils, each connected to a current amplifier and a magnetic-field-sensing probe, may be required to obtain the desired reduction.
  • the measured values of the probes may be supplied to an adaptive regulator which then controls the current amplifiers to bring about an optimum magnetic-field reduction.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Regulation Of General Use Transformers (AREA)
  • Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)

Abstract

La présente invention se rapporte à un procédé et un dispositif servant à amortir activement les champs magnétiques de fréquence industrielle qui se produisent, par exemple, à proximité de sous-stations de distribution, de réseau et de transformateurs de petite taille. On réalise ce procédé en générant un champ dirigé à l'opposé du champ magnétique non désiré provenant de l'équipement électrique de la station. On réalise ceci, par exemple, en plaçant un enroulement de compensation (8) le long des murs de la station. Une sonde de détection de champ magnétique (6) est placé sous le toit de la station de façon à ce qu'elle couvre une surface où l'amplitude du champ magnétique soit aussi proche que possible du champ moyen recouvrant la totalité du toit. La sonde de détection du champ magnétique est ensuite raccordée à un amplificateur de courant (9) qui, à son tour, alimente l'enroulement de compensation de sorte que l'amplitude du champ au niveau de la sonde soit considérablement réduite.
PCT/SE1994/000280 1993-04-28 1994-03-29 Procede et dispositif servant a amortir activement des champs magnetiques de frequence industrielle WO1994026084A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE9301426-4 1993-04-28
SE9301426A SE9301426D0 (sv) 1993-04-28 1993-04-28 Aktiv daempning av kraftfrekventa magnetfaelt

Publications (1)

Publication Number Publication Date
WO1994026084A1 true WO1994026084A1 (fr) 1994-11-10

Family

ID=20389741

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1994/000280 WO1994026084A1 (fr) 1993-04-28 1994-03-29 Procede et dispositif servant a amortir activement des champs magnetiques de frequence industrielle

Country Status (2)

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SE (1) SE9301426D0 (fr)
WO (1) WO1994026084A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997001948A1 (fr) * 1995-06-27 1997-01-16 Ab Volvo Dispositif et procede de reduction des champs magnetiques, et utilisation
EP0880311A1 (fr) * 1996-10-04 1998-11-25 Matsushita Electric Industrial Co., Ltd. Dispositif de protection contre les champs electromagnetiques
WO2000037280A1 (fr) * 1998-12-21 2000-06-29 Universidad Complutense De Madrid Dispositif de compensation du champ magnetique produit par les chemins de fer a traction electrique
WO2001045481A1 (fr) * 1999-12-13 2001-06-21 Valtion Teknillinen Tutkimuskeskus Procede d'attenuation d'interference dans une chambre a protection magnetique

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4373174A (en) * 1977-10-18 1983-02-08 Akesson Nils B Method for protective magnetization of vessels
GB2103395A (en) * 1981-06-06 1983-02-16 Licentia Gmbh An arrangement for compensating magnetic fields of movable bodies
DE3614527A1 (de) * 1986-04-29 1987-11-05 Bundesrep Deutschland Verfahren zur einstellung einer magnetischen eigenschutz (mes) - anlage zur kompensation des magnetischen stoerfeldes eines fahrzeuges, insbesondere schiffes
DE3723485A1 (de) * 1987-07-16 1989-01-26 Thomson Brandt Gmbh Induktive kochstelle
US4823081A (en) * 1984-02-04 1989-04-18 Licentia Patent-Verwaltungs-Gmbh Interference magnetic field compensation method which includes supplying a current to a coil to compensate the field
WO1990001861A1 (fr) * 1988-07-29 1990-02-22 Adaptive Control Limited Ameliorations relatives a la reduction de l'intensite de champs electromagnetiques

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4373174A (en) * 1977-10-18 1983-02-08 Akesson Nils B Method for protective magnetization of vessels
GB2103395A (en) * 1981-06-06 1983-02-16 Licentia Gmbh An arrangement for compensating magnetic fields of movable bodies
US4823081A (en) * 1984-02-04 1989-04-18 Licentia Patent-Verwaltungs-Gmbh Interference magnetic field compensation method which includes supplying a current to a coil to compensate the field
DE3614527A1 (de) * 1986-04-29 1987-11-05 Bundesrep Deutschland Verfahren zur einstellung einer magnetischen eigenschutz (mes) - anlage zur kompensation des magnetischen stoerfeldes eines fahrzeuges, insbesondere schiffes
DE3723485A1 (de) * 1987-07-16 1989-01-26 Thomson Brandt Gmbh Induktive kochstelle
WO1990001861A1 (fr) * 1988-07-29 1990-02-22 Adaptive Control Limited Ameliorations relatives a la reduction de l'intensite de champs electromagnetiques

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
MEAS. SCI. TECHNOL., Volume 2, No. 7, July 1991, H.J.M. TER BRAKE et al., "Improvement of the Performance of a Mu-Metal Magnetically Shielded Room by Means of Active Compensation", page 596 - page 601. *
MEAS. SCI. TECHNOL., Volume 4, No. 12, December 1993, H.J.M. TER BRAKE et al., "New Results in Active Noise Compensation for Magnetically Shielded Rooms", page 1370 - page 1375. *

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997001948A1 (fr) * 1995-06-27 1997-01-16 Ab Volvo Dispositif et procede de reduction des champs magnetiques, et utilisation
US5986355A (en) * 1995-06-27 1999-11-16 Ab Volvo Arrangement and method for reduction of magnetic fields and use thereof
EP0880311A1 (fr) * 1996-10-04 1998-11-25 Matsushita Electric Industrial Co., Ltd. Dispositif de protection contre les champs electromagnetiques
EP0880311A4 (fr) * 1996-10-04 2000-08-09 Matsushita Electric Ind Co Ltd Dispositif de protection contre les champs electromagnetiques
US6249006B1 (en) 1996-10-04 2001-06-19 Matsushita Electric Industrial Co., Ltd. Electromagnetic field shielding device
WO2000037280A1 (fr) * 1998-12-21 2000-06-29 Universidad Complutense De Madrid Dispositif de compensation du champ magnetique produit par les chemins de fer a traction electrique
ES2147536A2 (es) * 1998-12-21 2000-09-01 Univ Madrid Complutense Dispositivo de compensacion del campo magnetico producido por ferrocarriles de traccion electrica.
WO2001045481A1 (fr) * 1999-12-13 2001-06-21 Valtion Teknillinen Tutkimuskeskus Procede d'attenuation d'interference dans une chambre a protection magnetique
US6734353B2 (en) 1999-12-13 2004-05-11 Valtion Teknillinen Tutkimuskeskus Method for attenuating interference in a magnetically shielded room

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Publication number Publication date
SE9301426D0 (sv) 1993-04-28

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