US3156754A - Arrangement for balancing the power transmission line to a polyhase arc furnace - Google Patents
Arrangement for balancing the power transmission line to a polyhase arc furnace Download PDFInfo
- Publication number
- US3156754A US3156754A US15108361A US3156754A US 3156754 A US3156754 A US 3156754A US 15108361 A US15108361 A US 15108361A US 3156754 A US3156754 A US 3156754A
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- United States
- Prior art keywords
- balancing
- conductors
- power transmission
- transmission line
- arc furnace
- 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.)
- Expired - Lifetime
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- 230000005540 biological transmission Effects 0.000 title claims description 58
- 239000004020 conductor Substances 0.000 claims description 98
- 230000001939 inductive effect Effects 0.000 description 17
- 239000003990 capacitor Substances 0.000 description 16
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 12
- 238000009434 installation Methods 0.000 description 6
- 239000000155 melt Substances 0.000 description 5
- 230000008878 coupling Effects 0.000 description 4
- 238000010168 coupling process Methods 0.000 description 4
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- 125000004122 cyclic group Chemical group 0.000 description 4
- 238000003780 insertion Methods 0.000 description 4
- 230000037431 insertion Effects 0.000 description 4
- 238000001816 cooling Methods 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 229910000519 Ferrosilicon Inorganic materials 0.000 description 1
- 230000018199 S phase Effects 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 230000003466 anti-cipated effect Effects 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000002847 impedance measurement Methods 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 150000002505 iron Chemical class 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
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- 239000007787 solid Substances 0.000 description 1
- 238000013519 translation Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Images
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
- H05B7/02—Details
- H05B7/11—Arrangements for conducting current to the electrode terminals
-
- 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 present invention relates to the balancing of the power transmission line for a polyphase arc furnace, more particularly, to an arrangement of additional impedances which include ohmic resistances and capacitative and inductive reactances in at least two conductors of a 3-phase power transmission line so that the energy conversion of the electrode arcs in the arc furnace is equal.
- the different energy exchanges between the electrodes is caused by the various reactances and resistances in the conductors from the arc furnace transformer to the tips of the electrodes.
- the differences are caused by the parallel arrangement of the copper bus bars and cables of the power transmission line and of the various solid iron members of the arc furnace structure itself.
- Impedances calculated and made in accordance with the present inven tion permit a degree of symmetry and balancing of the power transmission of better than 6%, even if the balancing impedances deviate from the correct and calculated values by up to 30% It is therefore the principal object of the present invention to provide an arrangement for balancing the power transmission line to a polyphase arc furnace.
- the present invention essentially comprises the insertion of additional balancing impedances into one or more of the conductors of a power transmission line leading from the arc furnace transformer to the arc furnace.
- These balancing impedances may be in the form of ohmic resistances and reactances both capacitative and inductive. Combinations of both capacitative and inductive reactances may be inserted onto various of the conductors.
- J Q FIGURE 1 is a schematic view of the arc furna provided as additional balancing impedances in the three installation of the present invention showing the addition conductors of the power transmission line with the balof balancing capacitative reactances on the three gacancing reactances h i h f ll i value tors of the power transmission line;
- FIGURE 4 is a schematic view of the arc furnace ⁇ /g installation of the present invention showing an additional inductive balancing reactance on the central conductor Among these thrw Values Bi L6.
- E1, 2 3 flame is for and an additional capacitative reactance on one of th a given furnace a Smallest, a largest d a ⁇ medium l outer conductors; and to be denoted B B B respectively.
- FIGURE 5 is an elevational View of t ar fllfflace one selects the value B to equal the absolute value of installation of the present invention showing the added one f these three Values Bmm, Bmax, Bmed, only two of balancing impedances m unt d on the pp g arms the three conductors need balancing impedances to attain for the electrodes.
- v a the object of the invention.
- balancing impedances will have values which wherein the balancing inductive rcactance has the followmight deviate from the value required for the symmetry j Valua of the balancing impedance by an amount not greater g than plus or minus of the actual impedance.
- r 'r r are the ohmic resistances in the conductors (5) pertaining phases i, j, k, respectively and leading from g the transformer to the electrodes in the furnace.
- i, j, k X y B (i)/ (X X (Xkk Xki) represent conventional phases RST respectively or a 3 cyclic permutation thereof.
- X X X' is the self-inductivity oi"- tional balancing inductive reactance in the central conthe conductor pertaining to phases 1', j, k, respectively.
- duetor and an additional balancing capacitative reactance X is the mutual or coupling inductivity as between the In an Outer conductor having the following Values conductors of phases 1' and k.
- V is the secondary trans (6) former voltage and I is the average current in each 5, phase, voltages and currents assumed similar for each i med( )Q/ 1 k)+( u-' u ii ik) phase.
- X X X will denote the balancing impedances 5 to be inserted in phase conductors 1, 2,, 3, respectively, in accordance with the invention.
- the power transmission lines can also be balanced by providing additional ohmic resistances in the three conductors which resistances have the folusing the abbreviation.
- MP4 /:L (Xkk Xii) 7 (2) i( ii ik)+( ki ki)il+( k' 'i) 1 2v/ i+ i+ wherein i, j and k are again the three phases, r; the 3: 2( +R)( +R) 2( +R)( +R) ohmic resistance and the additional ohmic resistance 2 +R) (Tk+R) r r ,.r for one conductor isarbitrarily'selected.
- Equation 1 denotes the general rule, the followin Elektrow'arme, vol. 19, 8 (1961), having a title ing specific possibilities are included: which reads in translation Fundamentals for Balancing Additional balancing capacitativc reactanees can be Polyphase Arc Furnaces.
- the invention provides for a general rule regarding the provision of additional balancing impedances and values of the additional balancing reactances to achieve the foregoin conditions are as follows:
- Equation 11 All of the values necessary for the computation of Equation 11 can be determined by each arc furnace by impedance measurements. These measurements are done by withdrawing all of the electrodes from the melt in the furnace and lowering two of the electrodes to contact the melt surface so that there is no are therebetween. The third electrode remains above the melt.
- FIGURE 1 the electrodes of the arc furnace are indicated as E, E and E and being in contact with the melt in the furnace indicated as O.
- the 3-phase power transmission line has conductors 1, 2 and 3 which lead from the secondary of an arc furnace transformer T The conductors are then connected through groups of flexible cables to the conductors I I and I mounted on the supporting arms of the electrodes, which are respectively connected to the arc furnace electrodes.
- the power transmission line of FIGURE 1 is provided with additional balancing capacitative reactances on each of the conductors.
- These balancing reactances comprise laminated iron cores having air gaps which surround the conductor and coils positioned on the iron cores.
- Capacitors C C and C are then connected to the coils and switches S S and S are connected across the capacitors in order to bypass or shunt the capacitors when the electrodes are short-circuited.
- the balancing capacitors have values calculated in accordance with Equation 13.
- the power transmission line can be balanced by adding two inductive reactances X and X This is accomplished by positioning laminated iron cores L and L having air gaps around the conductors 1 and 2.
- the value of these additional inductive balancing reactances is obtained from Equation 11 if the term B is not 0, such as in Equations 13 but has the value of and B computed as follows:
- the energy between the arc furnace electrodes can also be balanced by positioning additional balancing capacitors on the outer conductors l and 3 suchas illustrated in FIGURE 3.
- capacitors C and C are connected to coils positioned on laminated iron cores surrounding the conductors It and 3.
- Switches S and 8;; are connected across the balancing capacitors C and C
- Equation 11 if B is assumed to be as follows:
- the power transmission line is balanced by inserting an additional inductive balacing reactance 1" in the central conductor 1 and an additional balancing capacitative reactance C" into one of the outer conductors such as l.
- the value of these additional balancing reactances can be determined from Equation 11 if the root term 3 is assumed to be as follows:
- B is the intermediate value of B B and B determined by Equations 15a and 11 in a manner analogous to those aforedescribed.
- the balancing reactances in FEGURE 4 are obtained by positioning a laminated iron core having an air gap and indicated as L surrounding the conductor 2 and a capacitor (3" connected with a coil positioned on a laminated iron .core surrounding the conductor 3.
- the present invention also provides for the balancing of the power transmission line by adding additional balancing ohmic resistance into the conductors.
- additional balancing ohmic resistances can be determined from Equation 10 if therein the values X are being assumed and the ohmic loss resistance of the conductors r which are known, are supplemented by ohmic resistances r to be imcdl determined.
- the equations now will only yield the differ- It is pointed out that one or the additional balancing ohmic resistances is arbitrarily selected.
- the additional balancing ohmic resistance can be ob tained by reducing the cross-sectional area of the conductors.
- the conductors can be cooled at those places Where they are provided with reduced cross-sectional areas.
- the conductors comprise a plurality of hollow conductors interconnected by a non-magnetic material such as a plastic and water circulated through the hollow conductors.
- FIGURE 5 With particular reference to FIGURE 5, the physical arrangement of the above-mentioned additional balancing impedances will next'be described.
- an arc furnace transformer A with the compensated leads originating from the secondary winding of the transformer and connected at A in a delta.
- Current transformers A are provided and are connected between the delta connections.
- the conductors of the power transmission line are then passed through a wall A; into the furnace chamber and are connected to flexible copper cables A which, in turn, are connected to water-cooled conductor tubes Ar, which are mounted on supporting arms A of electrodes A
- the supporting arms and the conductors mounted thereon are arranged in parallel for relatively long lengths of about several meters.
- This straight line arrangement of the conductors eliminates axial components of the magnetic fields which would result in excessive interference.
- the conductors can have a smaller cross-section than would be possible if the conductors were air-cooled.
- the additional reactances A are mounted on the supporting arms. Because of the smaller cross-section of the conductors, the weights of these additional reactances can be reduced.
- the additional reactances A are mounted on the supporting arms so that a minimum of a bending moment is produced on the arms. Since the weight of the additional reactance is of the order of only a fraction of the Weight of the electrode supporting arms themselves and of the electrode, the regulating speeds of the electrodes are not essentially attected.
- the values of the additional impedances such as the reactances or ohmic resistances are converted by the factor of the square of the voltage ratio of the transformer. It is apparent that these resistances will be changed when the transformer is connected to a line of another voltage.
- These additional resistances can either be positioned in the line on the voltage side or can be coupled by transformers.
- the present invention provides anaccurate arrangement for the determination of additional impedances to be inserted into the conductors of a power transmission line for balancing this arrangement. Not only can this arrangement be used to balance a power transmission line so as to obtain an equal energy of exchange bctweenthe electrodes of an arc furnace, but also to balance the high voltage side of a transformer.
- An arrangement for balancing the power trans mission line of a poiyphase arc furnace comprising an arc furnace having three electrodes therein, a3-phase power transmission line having three conductors with said conductors being respectively connected to said furnace electrodes, and additional balancing impedances in said power transmission line which impedances have the following value wherein indices i, j, k denote three phases and permutations thereof, with denoting anticyclic permutations and thereabove cyclic permutations, r being the ohmic conductor resistance, X the reactance thereof with similar indices in a pair of indices denoting self-reactance, unequal indices in a pair of indices denoting mutual reactance, and
- R is the arc resistance
- indices 1', j, k denote three phases and permutations thereof, with denoting anticyclic permutations and thereabove cyclic permutations, r being the ohmic conductor resistance
- X the reactance thereof with similar indices in a pair of indices denoting self-reactance, unequal indices in a pair of indices denoting mutual reactance.
- An arrangement for balancing the power transmission line of a polyphase are furnace as claimed in claim 2 wherein said capacitative balancing reactances comprise laminated iron cores having coils thereon with a core surrounding each of said conductors, and capacitors connected across each of said coils.
- An arrangement for balancing the power transmission line of a polyphase arc furnace comprising an arc furnace having three electrodes therein, a 3-phase power transmission line having three conductors respectively connected to said furnace electrodes, and additional balancing impedances in said power transmission line, said additional balancing impedances comprising an inductive balancing reactance on the center conductor and a capacitative balancing reactance on one of the outer conductors with said reactances having the value of wherein and wherein B equals the medium value of B B and B and R is the arc resistance, denoting anticyclic phase permutation.
- said inductive reactance comprises a laminated iron core having an air gap and surrounding said center conductor and said capacitative reactance comprises a laminated iron core surrounding an outer conductor with a coil positioned thereon and a capacitor connected to said coil.
- An arrangement for balancing the power transmission line of a polyphase arc furnace comprising an arc furnace having three electrodes therein, a 3-phase power transmission line having three conductors with said conductors being respectively connected to said electrodes, and ohmic balancing resistances provided in said areas/s4:
- a sit conductors which balancing resistances have the following values wherein indices 1', k and denote three phases and permutations thereof, with ()v denoting anticyciic permutations and thereof cyclic permutations, r with one index being ohmic conductor resistance, r with two indices being ohmic balancing resistance, X being the conductor reactance with similar indices in a pair denoting selfreactance, unequal indices in a pair denoting coupling reactance.
- An arrangement for balancing the power transmission line of a polyphase are furnace as claimed in claim 1 wherein said impedances comprise at least one laminated iron core having an air gap.
- An arrangement for balancing the high voltage side of an arc furnace transformer comprising an arc furnace transformer having a high voltage side and a low voltage side, a 3-phase power transmission line having 32 three conductors connected to said high voltage side of the transformer, balancing impedances in the power transmission line which balancing impedances have the following values 2v/ (n+ (n+ ski-er 2(r,+R) (r, +R)-2(r -l-R) (TH-R) -,-+R) (n+ wherein R is the arc resistance, said balancing impedances being converted by the square of the voltage ratio of the transformer for adaptation to various transformers and voltage sources.
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- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Furnace Details (AREA)
- Discharge Heating (AREA)
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEL37494A DE1165150B (de) | 1960-11-11 | 1960-11-11 | Anordnung an Zufuehrungsleitungen von Drehstromlichtbogenoefen zur Symmetrierung der Leistungsumsetzung |
| DEL39351A DE1195885B (de) | 1960-11-11 | 1961-06-26 | Anordnung an Zufuehrungsleitungen von Drehstromlichtbogenoefen zur Symmetrierung der Leistungsumsetzung |
| DEL0039873 | 1961-08-26 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3156754A true US3156754A (en) | 1964-11-10 |
Family
ID=27211397
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US15108361 Expired - Lifetime US3156754A (en) | 1960-11-11 | 1961-11-08 | Arrangement for balancing the power transmission line to a polyhase arc furnace |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US3156754A (de) |
| AT (1) | AT240610B (de) |
| DE (3) | DE1165150B (de) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3366725A (en) * | 1964-12-21 | 1968-01-30 | Watteredge Co | Balancing a three-phase power transmission system for an electric arc furnace |
| US3594486A (en) * | 1969-09-25 | 1971-07-20 | Heppenstall Co | Process and equipment for operating electric arc furnaces |
| US3857697A (en) * | 1973-03-05 | 1974-12-31 | Siderurgie Fse Inst Rech | Method of continuously smelting a solid material rich in iron metal in an electric arc furnace |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3814261A1 (de) * | 1988-04-27 | 1989-11-09 | Fuchs Systemtechnik Gmbh | Lichtbogenofen mit zuschaltbarer zusatz-reaktanz |
| DE10256324B4 (de) * | 2002-11-27 | 2018-02-15 | Pfisterer Kontaktsysteme Gmbh | Vorrichtung zum Steuern des Leiterstroms einer Wechselspannungs-Hochstromleitung |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2758144A (en) * | 1952-12-15 | 1956-08-07 | Asea Ab | Compensation means in three-phase electric arc furnace |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE408370C (de) * | 1925-01-22 | Aeg | Verkettetes Mehrphasenkraftuebertragungssystem | |
| DE432213C (de) * | 1926-08-02 | Allg Elek Citaets Ges Fa | Verkettetes Mehrphasenkraftuebertragungssystem | |
| DE549950C (de) * | 1925-06-23 | 1932-05-11 | Siemens Schuckertwerke Akt Ges | Einrichtung zum Ausgleich der unsymmetrischen Belastung eines Mehrphasennetzes |
| DE732004C (de) * | 1940-08-14 | 1943-02-19 | Siemens Ag | Einrichtung zum Schutz eines Reihenkondensators |
| DE874042C (de) * | 1948-10-02 | 1953-04-20 | Demag Elektrometallurgie Gmbh | Anordnung zum Symmetrieren von Dreiphasen-Hochstromleitungen |
| DE914873C (de) * | 1951-10-10 | 1954-07-12 | Licentia Gmbh | Anordnung zur Spannungssymmetrierung eines mehrphasigen Netzteiles |
| DE1022716B (de) * | 1955-03-30 | 1958-01-16 | Bbc Brown Boveri & Cie | Verfahren zur Anpassung der in den Hochstromzuleitungen eines Lichtbogenofens liegenden Impedanz an den Betriebszustand des Ofens |
| DE1036999B (de) * | 1956-03-27 | 1958-08-21 | Demag Elektrometallurgie Gmbh | Drehstromleitersystem, insbesondere fuer Lichtbogenoefen |
| DE1068400B (de) * | 1957-05-24 | 1959-11-05 | Siemens-Planiawerke Ag | Anordnung zur regelung der stromversorgung von wechselstrom gespeisten hochstrom widerstandsofen |
-
1960
- 1960-11-11 DE DEL37494A patent/DE1165150B/de active Pending
-
1961
- 1961-06-26 DE DEL39351A patent/DE1195885B/de active Pending
- 1961-08-26 DE DE19611440496 patent/DE1440496A1/de active Pending
- 1961-11-08 US US15108361 patent/US3156754A/en not_active Expired - Lifetime
- 1961-11-08 AT AT841461A patent/AT240610B/de active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2758144A (en) * | 1952-12-15 | 1956-08-07 | Asea Ab | Compensation means in three-phase electric arc furnace |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3366725A (en) * | 1964-12-21 | 1968-01-30 | Watteredge Co | Balancing a three-phase power transmission system for an electric arc furnace |
| US3594486A (en) * | 1969-09-25 | 1971-07-20 | Heppenstall Co | Process and equipment for operating electric arc furnaces |
| US3857697A (en) * | 1973-03-05 | 1974-12-31 | Siderurgie Fse Inst Rech | Method of continuously smelting a solid material rich in iron metal in an electric arc furnace |
Also Published As
| Publication number | Publication date |
|---|---|
| DE1165150B (de) | 1964-03-12 |
| DE1440496A1 (de) | 1969-05-22 |
| AT240610B (de) | 1965-06-10 |
| DE1195885B (de) | 1965-07-01 |
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