EP0801405A2 - Procédé de préséchage d'un bloc de bobine contenant au moins un enroulement et isolation solide et dispositif pour la mise en oeuvre de ce procédé - Google Patents

Procédé de préséchage d'un bloc de bobine contenant au moins un enroulement et isolation solide et dispositif pour la mise en oeuvre de ce procédé Download PDF

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Publication number
EP0801405A2
EP0801405A2 EP97810170A EP97810170A EP0801405A2 EP 0801405 A2 EP0801405 A2 EP 0801405A2 EP 97810170 A EP97810170 A EP 97810170A EP 97810170 A EP97810170 A EP 97810170A EP 0801405 A2 EP0801405 A2 EP 0801405A2
Authority
EP
European Patent Office
Prior art keywords
winding
windings
heating
autoclave
coil block
Prior art date
Legal status (The legal status 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 status listed.)
Granted
Application number
EP97810170A
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German (de)
English (en)
Other versions
EP0801405A3 (fr
EP0801405B1 (fr
Inventor
Paul Gmeiner
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ABB Schweiz AG
Original Assignee
Micafil Vakuumtechnik AG
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 Micafil Vakuumtechnik AG filed Critical Micafil Vakuumtechnik AG
Publication of EP0801405A2 publication Critical patent/EP0801405A2/fr
Publication of EP0801405A3 publication Critical patent/EP0801405A3/xx
Application granted granted Critical
Publication of EP0801405B1 publication Critical patent/EP0801405B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/08—Cooling; Ventilating
    • H01F27/10—Liquid cooling
    • H01F27/12—Oil cooling
    • H01F27/14—Expansion chambers; Oil conservators; Gas cushions; Arrangements for purifying, drying, or filling

Definitions

  • the invention is based on a method for predrying a coil block containing at least one winding, in which the at least one winding is heated with current under reduced pressure in a gas-tight housing.
  • a method for predrying a coil block containing at least one winding in which the at least one winding is heated with current under reduced pressure in a gas-tight housing.
  • Such a method is generally used to stabilize the coil block before installation in an electrical machine or an electrical apparatus, for example a transformer.
  • the method can also be used to adapt the geometric dimensions of the coil block to parts of the machine or apparatus which support the coil block and which support it to absorb short-circuit forces.
  • JP 5006833 A A method of the type mentioned is described in JP 5006833 A.
  • a winding of a coil block is heated under vacuum in a drying oven with direct current.
  • Moisture emerging from the heated coil block is removed from the interior of the drying oven by means of a vacuum device.
  • a temperature controller based on a thermocouple keeps the temperature of the coil block within an optimal range for rapid and effective pre-drying of the coil block.
  • the invention has for its object to provide a method for pre-drying a coil block containing at least one winding and solid insulation, which enables particularly gentle removal of moisture and which can nevertheless be carried out particularly quickly and in an energy-saving manner.
  • the method according to the invention is characterized in that the parts of the solid insulation which, like the barrier insulation in particular, are not in direct contact with the winding heated up to current are now heated not only by heat conduction but also by convection and heat radiation. Therefore, the coil block is heated particularly evenly and the moisture present in the solid insulation is removed very gently.
  • the air circulating in the gas-tight housing is only heated to a temperature lower than the temperature of the coil block. Therefore, apparatus housed inside the housing, such as hydraulic press devices provided in particular for pressurizing coil blocks, requires little maintenance.
  • 1 denotes a vacuum-tight autoclave connected to a vacuum pump 3 via a through valve 2, which can be connected to circulating air via a ventilation valve 4.
  • the autoclave accommodates three windings 51, 52, 53 and 61, 62, 62 and 71, 72 and coil blocks 5 and 6 and 7, respectively, which do not have solid insulation.
  • the windings, e.g. 51, 52, 53, each coil block, e.g. 5, can be of identical design and are connected in parallel to one another.
  • Two power connections to the windings of each coil block are performed by means of unspecified bushings from the inside of the autoclave 1 to a switching device 8, which in turn is operatively connected to the output of a DC power source 9.
  • the direct current source 9 has a transformer 10 and a rectifier 11 acting on the changeover switch 8 and a step switch 12 connected between the transformer 10 and the rectifier 11.
  • a current is connected in a connecting line between the output of the rectifier 11 and an input of the switching device 8. and voltage converter 13 arranged.
  • the output signals of the current and voltage converter 13 act on a control device 14.
  • This control device is operatively connected to the transformer 10, the tap changer 12, the rectifier 11 and the switching device 8.
  • the coil blocks 5, 6, 7 to be pre-dried in the autoclave 1 are heated from time t 0 with direct current of a thickness predetermined by the dimensions of the coil blocks or the windings 51, 52, 53, 61, 62, 63, 71 and 72.
  • Direct current is particularly suitable because the heating voltage can then be selected to be relatively low and, in contrast to alternating current, reactive power compensation is then omitted.
  • the current strength is set in a particularly simple manner via the tap changer 12 actuated by the control device 14. If all windings are of the same design, this is achieved in that three switching points 81, 82 and 83 provided in the switching device 8 are closed.
  • windings 51, 52, 53 or 61, 62, 63 or 71, 72 are of the same design in each of the coil blocks 5 or 6 or 7 and are each assigned to a phase of a three-phase current, they are designed differently in each of the coil blocks , the windings of the individual coil blocks are gradually heated up. This is achieved in that the two switching points 82 and 83 are initially open and the switching point 81 is closed. After a heating period predetermined by monitoring the winding temperature, the switching point 81 is then opened and, after the switching point 82 is closed, the coil block 6 is heated with direct current. In a corresponding manner, the coil block 7 and subsequently all the coil blocks in succession in a cyclic manner are heated again.
  • windings within a coil block are designed differently, for example as high and low voltage windings of a transformer, one of the switching points, for example 81, can be connected to the high voltage winding and another of the switching points, for example 82, can be connected to the low voltage winding.
  • the windings provided in a single coil block can then be heated in a staggered manner over time.
  • the winding temperature can be determined indirectly via the current and voltage values of the direct current output by the current and voltage converter or from a measurement of the electrical resistance of the windings. Alternatively or additionally, it is also possible to determine this temperature by sensors which are guided through the autoclave housing to the windings in question.
  • the air in the autoclave 1 is heated under reduced pressure.
  • the ventilation valve 4 is closed and the air pressure in the autoclave is reduced to a few hundred mbar, for example 500 mbar, by pumping air out through the open passage valve 2 and the vacuum pump 3.
  • the air pressure should be less than atmospheric pressure and preferably between 950 and 500 mbar.
  • the autoclave 1 and thus also the air in the autoclave are heated.
  • the combined heating with direct current and with air ensures that the heat required for pre-drying the solid insulation of the coil blocks is supplied simultaneously from the inside and outside. This ensures particularly quick and gentle drying.
  • Water bound in the solid insulation is led away from the heated windings to the surfaces of the solid insulation and is absorbed by the air as water vapor.
  • parts of the solid insulation such as barrier insulation arranged between two windings, which are not in direct contact with a winding of the coil block, are heated particularly quickly and in a uniform manner, and that from the Solid insulation leaking water is quickly removed from the coil blocks.
  • the reduction in air pressure promotes the escape of water from the solid insulation.
  • the air pressure in the autoclave 1 is reduced by the vacuum pump 3 to below 500 mbar during heating, but to a maximum of 0.1 mbar for reasons of economy.
  • the current strength of the direct current is increased. This is mainly because, due to the reduced pressure in the autoclave 1, water evaporates from the solid insulation.
  • a new heating cycle begins at time t 3 .
  • the amperage of the direct current is reduced. It is set so that it is smaller than in the previous cycle. This is due to the fact that on the one hand not as much water can be removed from the solid insulation as at the beginning of the heating, and on the other hand that the autoclave 1 is almost heated to its target temperature, for example 70 or 80 ° C.
  • the windings are further heated by the direct current and, accordingly, the solid insulation by heat, which is given off by the windings and the circulating air.
  • the autoclave 1 reaches its final temperature.
  • the heating of the autoclave is now throttled so that its temperature T a remains constant at the final temperature.
  • an upper winding temperature is reached at time t 4 .
  • the air pressure in autoclaves is now continuously reduced.
  • the strength and duration of the direct current are set in such a way that the upper winding temperature is kept constant. This is achieved in that when the windings are kept at the upper winding temperature, the direct current is interrupted when the temperature T w of the windings exceeds the upper winding temperature by a predetermined limit value. If the winding temperature T w drops below a predetermined lower limit value when the direct current is interrupted, the direct current is switched on again.
  • the autoclave 1 is slowly cooled by further reducing the heating. From time t 4 , the residual moisture is removed from the solid insulation practically under vacuum with low energy input.
  • the coil blocks are subjected to an evenly acting pressing pressure.
  • This pressing pressure is generated by the pressing device 15 and can have a pulsating effect in accordance with the air pressure in the autoclave.
  • the coil blocks are stabilized by the pressing pressure and adapted to specified dimensions.
  • the coil blocks are sufficiently pre-dried and, after cooling and opening the autoclave, can be installed in the electrical equipment or machines provided for this purpose.
  • the switching device 8 is omitted and the three coil blocks 5, 6, 7 are each heated by one of three direct current sources 9, 9 ', 9''.
  • These direct current sources each contain a rectifier, a transformer and a tap changer connected between the transformer and the rectifier.
  • the for the The measurement data required for temperature determination are provided by three current and voltage converters 13, 13 ′, 13 ′′, which are each arranged in the current supply to one of the three coil blocks 5, 6, 7.
  • three differently designed coil blocks can be heated simultaneously with direct current and kept at temperature.
  • the direct current sources 9, 9 'and 9' 'shown in FIGS. 1 and 3 do not necessarily have to contain a transformer with a downstream tap changer. They can also have a controllable transformer, the controllable output voltage of which is led directly to the input of the rectifier.
  • a three-phase, low-frequency alternating current with frequencies of approximately 0.1 to approximately 20 Hz is used as the heating current.
  • This current is supplied by an AC-AC converter 90 and is guided through unidentified bushings through the wall of a housing 1 ′ of a transformer 100, which is designed to be gas-tight in accordance with the autoclave 1, to its primary windings 101, which are connected as a star, for example.
  • the secondary windings 102 of the transformer 100 are short-circuited.
  • the windings 101 and 102 are part of a solid insulation and a coil block 103 containing a magnetic core.
  • heating is carried out with circulating air in accordance with the two devices described above.
  • Heated air is advantageously supplied via the ventilation valve 4 and distributed throughout the housing 1 'by the circulating air fan 16.
  • the combination of the low-frequency AC heating and the thermally heated air achieves particularly efficient predrying of the solid insulation, the magnetic core and the coil blocks of the transformer 100 containing the windings 101 and 102.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • General Induction Heating (AREA)
  • Drying Of Solid Materials (AREA)
EP19970810170 1996-04-09 1997-03-21 Procédé de préséchage d'un bloc de bobine contenant au moins un enroulement et isolation solide et dispositif pour la mise en oeuvre de ce procédé Expired - Lifetime EP0801405B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19614004 1996-04-09
DE1996114004 DE19614004A1 (de) 1996-04-09 1996-04-09 Verfahren zur Vortrocknung eines mindestens eine Wicklung und Feststoffisolationen enthaltenden Spulenblocks und Vorrichtungen zur Durchführung dieses Verfahrens

Publications (3)

Publication Number Publication Date
EP0801405A2 true EP0801405A2 (fr) 1997-10-15
EP0801405A3 EP0801405A3 (fr) 1997-10-29
EP0801405B1 EP0801405B1 (fr) 2006-01-18

Family

ID=7790797

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19970810170 Expired - Lifetime EP0801405B1 (fr) 1996-04-09 1997-03-21 Procédé de préséchage d'un bloc de bobine contenant au moins un enroulement et isolation solide et dispositif pour la mise en oeuvre de ce procédé

Country Status (2)

Country Link
EP (1) EP0801405B1 (fr)
DE (2) DE19614004A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10035948A1 (de) * 2000-07-21 2002-02-07 Alstom Verfahren und Vorrichtung zum Trocknen einer Isolation eines elektrischen Geräts, insbesondere eines Transformators oder einer Drossel oder dergleichen
US6634117B2 (en) 2001-04-24 2003-10-21 Micafil Ag Method for drying an active part and device for carrying out this method
DE102011053288A1 (de) 2011-09-06 2013-03-07 Wilhelm Hedrich Vakuumanlagen Gmbh & Co. Kg Vorrichtung zum Aufheizen und Trocknen eines Gutes
CN108712037A (zh) * 2018-06-01 2018-10-26 安徽晋煤中能化工股份有限公司 一种6kV同步电动机定子绕组干燥方法

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2146657A5 (fr) * 1971-07-22 1973-03-02 Jeumont Schneider
JPS57102007A (en) * 1980-12-17 1982-06-24 Fuji Electric Co Ltd Drying of internal parts of inductive electric appliances
DE3927964A1 (de) * 1989-08-24 1991-03-21 Leybold Ag Stromversorgung zum trocknen von transformator-teilen
FR2654249B1 (fr) * 1989-11-09 1992-01-03 Cahueau Colette Procedes de sechage impregnation polymerisation controles.
EP0543181B1 (fr) * 1991-11-18 1998-03-25 MICAFIL Vakuumtechnik AG Procédé de séchage des isolants solides de transformateurs en particulier de transformateurs pour installation de distribution et dispositif de mise en oeuvre du procédé

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10035948A1 (de) * 2000-07-21 2002-02-07 Alstom Verfahren und Vorrichtung zum Trocknen einer Isolation eines elektrischen Geräts, insbesondere eines Transformators oder einer Drossel oder dergleichen
US6634117B2 (en) 2001-04-24 2003-10-21 Micafil Ag Method for drying an active part and device for carrying out this method
DE102011053288A1 (de) 2011-09-06 2013-03-07 Wilhelm Hedrich Vakuumanlagen Gmbh & Co. Kg Vorrichtung zum Aufheizen und Trocknen eines Gutes
WO2013034382A1 (fr) 2011-09-06 2013-03-14 Wilhelm Hedrich Vakuumanlagen Gmbh & Co. Kg Dispositif de chauffage et de séchage d'un article
CN108712037A (zh) * 2018-06-01 2018-10-26 安徽晋煤中能化工股份有限公司 一种6kV同步电动机定子绕组干燥方法

Also Published As

Publication number Publication date
DE59712551D1 (de) 2006-04-06
DE19614004A1 (de) 1997-10-16
EP0801405A3 (fr) 1997-10-29
EP0801405B1 (fr) 2006-01-18

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