WO2007014535A1 - Transformer system for electrical arc furnaces having three electrodes - Google Patents
Transformer system for electrical arc furnaces having three electrodes Download PDFInfo
- Publication number
- WO2007014535A1 WO2007014535A1 PCT/DE2005/001361 DE2005001361W WO2007014535A1 WO 2007014535 A1 WO2007014535 A1 WO 2007014535A1 DE 2005001361 W DE2005001361 W DE 2005001361W WO 2007014535 A1 WO2007014535 A1 WO 2007014535A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- phase
- transformers
- transformer system
- electrodes
- transformer
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B7/00—Heating by electric discharge
- H05B7/005—Electrical diagrams
Definitions
- the invention relates to a transformer system for an electric arc furnace with three electrodes.
- a transformer In the case of the extreme currents on the secondary side, switching in the high-current circuit is technically difficult or impossible, and thus the furnace must be switched on the primary medium-voltage side.
- the setting of the secondary voltage is also set on the primary winding of the transformer via tap changer.
- the in the Power supply usual medium voltage switches are limited on the power side and also have only a limited life of about 10,000 switching cycles. An increase in the switching capacity leads to a partially drastic reduction in the service life of the switchgear. Electric arc furnaces are therefore subject to certain technical limitations in terms of performance.
- DE 30 24 223 C2 discloses an electric arc furnace in which up to four sets of three electrodes each and a three-phase transformer are arranged in an oven above the molten bath. The circuit of each transformer system takes place in the sense of a three-phase triangle circuit.
- Electric arc furnace with multiple electrode transformer systems known, in which two sets, each consisting of three electrodes facing each other in an elongated furnace.
- the wiring of the respective phases takes place in such a way that the phase sequences of the two transformers face each other in the reverse order.
- a three-electrode electric arc furnace transformer system comprising at least two three-phase transformers.
- the three phases of the three-phase transformers are each connected in parallel to one of the electrodes.
- the transformer system according to the invention thus has the advantage of being able to supply an increased electric power to a single electric arc furnace with only three electrodes. It takes on a dependent
- the circuit of the individual transformers in the sense of a synchronous circuit.
- the dependent circuit can continue to safely operate the electric arc furnace in the event of failure of one of the three-phase transformers at reduced power by disconnecting the relevant inactive transformers.
- the three-phase transformers are switched on and off within a time window of a maximum of 100 ms. As a result, dangerous voltages in the transformer system are largely avoided.
- a secondary-side circuit of the high-current lines is not necessary in an advantageous manner. It can be provided that the three-phase transformers are already internally triangulated. The two terminals of the three secondary coils of a three-phase transformer are already within the transformer in the sense of a
- the lines from the three-phase transformers exit at a right angle to a housing wall of the transformer.
- the three phases of all involved three-phase transformers are interconnected with high current rails.
- the involved three-phase transformers can thus be connected to one another in an advantageous manner using rigid, and therefore solid, lines.
- the high-current rails are preferably water-cooled.
- the electrical paths are as short as possible, which is particularly advantageous with regard to the high secondary currents and the resulting high magnetic alternating feeder and keeps the furnace reactance low.
- the individual transformers of the transformer system can thus be arranged in an advantageous manner so spatially that the distance to magnetic parts, ie about parts of
- the high-current rails between the at least two three-phase transformers extend in three planes one above the other.
- the Terminals for one phase thus leave a three-phase transformer in different heights.
- the three-phase transformers can be combined in an advantageous manner with high-current rails electrically symmetrical and without crossing.
- two of the high-current rails of a phase meet at an angle of between 45 ° and 180 °.
- the transformer system can be realized in an advantageous manner as possible, in that the three-phase transformers involved are spatially arranged in such a way that the electrical paths are short and the distance to magnetic materials as far as possible.
- one phase of a three-phase transformer with flexible lines is connected to the corresponding phase of the other three-phase transformers of the transformer system.
- the flexible high-current lines are preferably water-cooled and allow the parallel connection according to the invention of several three-phase transformers for an electric arc furnace with only minimal restrictions with regard to the arrangement of the transformers involved and of the furnace.
- the inventive performance increase for an electric arc furnace can be realized even in unfavorable spatial conditions.
- the flexible lines are each conductively connected to one phase of the three-phase transformers involved in each case one of the three electrodes of the arc furnace.
- the need for electrical contacts can thus be minimized.
- Figure 1 is a schematic representation of an electrical
- FIG. 2 a shows a detailed view of a transformer system according to a second embodiment of the invention in FIG
- FIG. 3 shows a schematic representation of an electric arc furnace with a transformer system according to a third embodiment of the present invention.
- FIG. 1 shows a schematic plan view of the transformer system 1 with the electric arc furnace 2.
- three electrodes 202 are arranged above the electric arc furnace with the melt.
- the transformer system 1 further comprises a switchgear 120 and, as shown here, two three-phase transformers 100, hereinafter also referred to as
- Transformer refers to.
- the transformers 100 are connected on the primary side via conductive connections 123 to the switchgear 120.
- all transformers 100 are switched on and off via a medium-voltage switch 121 by a switching unit 122 as a function of one another.
- the switching unit 122 enables the time-synchronized switching on and off of the medium voltage switches 121, preferably within one Time window of 100 ms.
- the switchgear 120 also allows the safe operation of the arc furnace 2 with only a part of the intended transformers 100, for example in the event of failure of one or more transformers 100.
- the switching unit 122 in conjunction with the medium-voltage switches 121, ensures the operation of the transformer system 1 with a plurality of transformers 100 in the sense of excluding human and plant hazard.
- a secondary-side circuit of the transformers 100 is not practical because of the extreme secondary currents in the range of 100 kA, and all participating transformers 100 are thus firmly connected to one another on the secondary side by contact points 105.
- z. B. during operation with only one of the two transformers 100 shown in Figure 2 is due to the secondary side merger a back-transformed voltage on the primary side of the non-active transformers 100 at.
- the medium-voltage switch 121 of the switchgear 120 then optionally disconnect the primary side, and a dangerous voltage can not leave the switchgear 120.
- the transformers 100 are advantageously internally trian- gulated. This means that the total of six terminals of the three coils of the three-phase transformer 100 are already connected internally in the sense of a three-phase triangle circuit.
- a housing wall 110 of the transformers 100 therefore has only three high current terminals u, v and w on the secondary side.
- these three phases are parallel to one another by high-current rails 101 at contact points 105. connected. From these contact points 105, further high-current rails can initially lead to the electric arc furnace 2, or, as shown here, the electrodes 202 of the electric arc furnace 2 can be connected to the contact points 105 with flexible high-current lines 102. be sen. Both the high-current rails 101 and the flexible high-current lines 102 are advantageously water-cooled.
- the high-current rails 101 exit at a right angle to the housing wall 110 of the transformers 100. They meet at the contact points 105 at an angle ß together.
- the individual transformers 100 of the transformer system 1 can be spatially arranged in terms of the shortest possible electrical paths. At the same time in this embodiment, possible large distances of the high-side induced magnetic fields of magnetic materials are ensured.
- Another advantage of this embodiment is the construction of the transformer system 1 with a plurality of transformers 100 in an arrangement that is as symmetrical as possible electrically.
- FIG. 2a shows a detailed view of the transformers 100 according to a second embodiment of the present invention.
- the transformers have a housing wall 111 from which high busbars 101 exit.
- the transformers Like a front view of a
- Transformer 100 in Figure 2b shows, three terminal units 115 are provided on the housing wall 111 for each phase u, v and w. According to this second embodiment of the present invention, these three terminal units 115 are stacked in three planes.
- This embodiment has the advantage that the three phases can be connected at contact points 105 by high-current rails 101 without crossing each other, and the length of the rails 101 can be made as short as possible.
- the participating transformers 100 such as the two transformers 100 shown here, can thus be arranged as close together as possible.
- Figure 3 shows schematically a transformer system 1 with an electric arc furnace 2 according to a third embodiment of the present invention. As already described for FIG.
- the transformer system 1 has two, but in general a plurality of three-phase transformers 100 and a switchgear 120.
- the participating transformers 100 are connected on the primary side with conductive connections 123 to the switchgear 120.
- a switching unit 122 in the switchgear 120 actuates a plurality of medium voltage switches 121 as a function of one another. This dependent switching by the switching unit 122 is analogous to the first embodiment in FIG. 1, again in the sense of avoiding a danger to people and equipment.
- the transformers 100 have a housing wall 112, to which flexible lines 102 are connected to terminal units, not shown. With these flexible lines 102, the three phases u, v and w of the transformers 100 involved are connected in parallel to the electrodes 202 of the arc furnace 2.
- the electrodes 202 which are located over a metal bath 201 of the arc furnace 2, can again be arranged on an electrode arm (not shown).
- this third embodiment of the present invention is that the greatest possible flexibility with respect to the spatial structure of the transformers 100 involved in the electric arc furnace 2 is ensured.
- This embodiment thus also allows the use according to the invention of a plurality of transformers 100 in an electric arc furnace 2 even in unfavorable spatial conditions.
- an arrangement of a plurality of transformers 100 one above the other is conceivable, which can be connected by flexible lines 102 in an advantageous manner with the shortest possible lines 102 without crossing the electrodes 202 of the arc furnace 2.
Abstract
Description
Claims
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN2005800512564A CN101228811B (en) | 2005-08-02 | 2005-08-02 | Voltage transformer system for electric arc furnace with three electrodes |
UAA200801310A UA89835C2 (en) | 2005-08-02 | 2005-08-02 | Transformer system for electrical arc furnace having three electrodes |
DE112005003716T DE112005003716A5 (en) | 2005-08-02 | 2005-08-02 | Transformer system for electric arc furnaces with three electrodes |
EP05776725A EP1911329A1 (en) | 2005-08-02 | 2005-08-02 | Transformer system for electrical arc furnaces having three electrodes |
PCT/DE2005/001361 WO2007014535A1 (en) | 2005-08-02 | 2005-08-02 | Transformer system for electrical arc furnaces having three electrodes |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/DE2005/001361 WO2007014535A1 (en) | 2005-08-02 | 2005-08-02 | Transformer system for electrical arc furnaces having three electrodes |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2007014535A1 true WO2007014535A1 (en) | 2007-02-08 |
Family
ID=35906581
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/DE2005/001361 WO2007014535A1 (en) | 2005-08-02 | 2005-08-02 | Transformer system for electrical arc furnaces having three electrodes |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP1911329A1 (en) |
CN (1) | CN101228811B (en) |
DE (1) | DE112005003716A5 (en) |
UA (1) | UA89835C2 (en) |
WO (1) | WO2007014535A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2017220726A1 (en) * | 2016-06-23 | 2017-12-28 | Sms Group Gmbh | Electric reduction device |
WO2019094921A1 (en) * | 2017-11-13 | 2019-05-16 | Chromalox, Inc. | Medium voltage molten salt heater and molten salt thermal energy storage system including same |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2829312A1 (en) * | 2001-08-29 | 2003-03-07 | Electricite De France | DIRECT CURRENT SUPPLY DEVICE FOR ARC FURNACE |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN2248379Y (en) * | 1995-03-11 | 1997-02-26 | 西南交通大学 | Star-multitriangle wiring balance transformer |
CN2298617Y (en) * | 1997-02-14 | 1998-11-25 | 西安山秦冶金机电设备厂 | Ore-smelting electric furnace low-frequency power supply complete apparatus |
-
2005
- 2005-08-02 EP EP05776725A patent/EP1911329A1/en not_active Withdrawn
- 2005-08-02 WO PCT/DE2005/001361 patent/WO2007014535A1/en active Application Filing
- 2005-08-02 DE DE112005003716T patent/DE112005003716A5/en not_active Withdrawn
- 2005-08-02 CN CN2005800512564A patent/CN101228811B/en not_active Expired - Fee Related
- 2005-08-02 UA UAA200801310A patent/UA89835C2/en unknown
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2829312A1 (en) * | 2001-08-29 | 2003-03-07 | Electricite De France | DIRECT CURRENT SUPPLY DEVICE FOR ARC FURNACE |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2017220726A1 (en) * | 2016-06-23 | 2017-12-28 | Sms Group Gmbh | Electric reduction device |
WO2019094921A1 (en) * | 2017-11-13 | 2019-05-16 | Chromalox, Inc. | Medium voltage molten salt heater and molten salt thermal energy storage system including same |
Also Published As
Publication number | Publication date |
---|---|
CN101228811B (en) | 2011-08-10 |
UA89835C2 (en) | 2010-03-10 |
EP1911329A1 (en) | 2008-04-16 |
CN101228811A (en) | 2008-07-23 |
DE112005003716A5 (en) | 2008-07-10 |
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