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WO2006089315A1 - Commande de four a arc electrique - Google Patents

Commande de four a arc electrique Download PDF

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Publication number
WO2006089315A1
WO2006089315A1 PCT/ZA2006/000024 ZA2006000024W WO2006089315A1 WO 2006089315 A1 WO2006089315 A1 WO 2006089315A1 ZA 2006000024 W ZA2006000024 W ZA 2006000024W WO 2006089315 A1 WO2006089315 A1 WO 2006089315A1
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Prior art keywords
furnace
electrode
arc
values
estimated
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English (en)
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Ian James Barker
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Mintek
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Mintek
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    • 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
    • H05B7/144—Power supplies specially adapted for heating by electric discharge; Automatic control of power, e.g. by positioning of electrodes
    • H05B7/148—Automatic control of power
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/25—Process efficiency

Definitions

  • This invention relates to the operation and control of an arc furnace.
  • arc furnace covers: (a) open-arc furnaces where the arc is partly or totally exposed, e.g in steel scrap melting;
  • each electrode is connected to a respective phase of a 3-phase alternating current (a.c.) supply.
  • a.c. 3-phase alternating current
  • An arc furnace requires instrumentation for monitoring its electrical circuit and for controlling its electrodes. Problems are however associated with the measurement of circuit parameters of an arc furnace. Direct measurement, which requires a connection to the hearth of the furnace, is troublesome and is prone to errors of up to about 3 ⁇ '%. Without a hearth connection there is however a problem with a lack of observability.
  • U.S. patent No. 4296269 describes concepts, some of which have been embodied in a controller which is known commercially as a Minstral controller, which does not require a hearth connection and which overcomes this problem by using an assumption about the reactances, generically termed the
  • the reactances are inter-related in the manner described in the aforementioned patent, they constitute 1 unknown instead of 3 (in a 3-electrode furnace).
  • the reactances do not necessarily have to be exactly equal to achieve this for they could be offset from one another, or be in fixed ratios to one another, by predetermined amounts.
  • the controller is then able to produce a value for each of the 3 resistances and one value characterising the reactances.
  • the values of the resistances determined in this way are significantly more accurate and reliable than those measured directly, and are therefore very useful in the operation of the furnace.
  • the reactances do however vary slightly, and do not exactly follow whatever assumption is made, but it appears that the resulting errors in the values of the calculated resistances are small in comparison with directly measured values. Similar considerations would apply in a furnace with more than 3 electrodes.
  • Minstral controller cannot distinguish between the three reactances in a furnace, because of the basic assumption that these reactances are inter-related. These reactances are caused primarily by the inductance from the magnetic field around the conductors in association with the a.c. circuit, but there is also a small pseudo-reactance that is caused by the non-linear behaviour of any arcs in the circuit. There could potentially be advantages if the pure magnetic inductance (i.e. excluding any contributions from arcs) could be measured individually for each electrode, as this would provide useful information for the operation of the furnace, such as an estimation of electrode lengths. Any deviations in these magnetic inductances would not be large (e.g. a variation of up to about 0.1 milli-ohm in about 1.2 milli-ohm), which is why the effect of this on the Minstral controller's estimation of the resistances is not major.
  • the magnetic inductance associated with any one electrode will increase if the electrode grows longer. It has been observed that the reactance will change by, very roughly, about 0.10 to 0.13 milli-ohm for every metre that the electrode length changes. If the equal-reactance assumption is used on a furnace where the electrode lengths are significantly unbalanced, then any differences between the reactances will reflect as similar errors in the calculated resistances. Hence if the typical resistances are, say, 1.0 milli-ohm, and if one of the electrodes is, say, 1.0
  • control of the electrical circuit is only part of the control problem of a submerged-arc ferro-alloy furnace.
  • the other major part is the control of the metallurgy, and in particular the control of the carbon balance.
  • the reaction is usually the reduction of a metal oxide ore by carbon.
  • the electricity flowing through the reaction zone provides the chemical heat required for the reaction.
  • the raw materials are normally a mixture of ores and a carbonaceous reducing agent, optionally with a small quantity of fluxes to get the slag melting temperatures correct.
  • the ores and fluxes melt, while the carbonaceous reducing agent remains as solid particles.
  • the carbon particles react relatively slowly with the metal oxide ore, in a fixed stoichiometric ratio. If there is an excess of carbon in the feed materials, then carbon will tend to accumulate in the reaction zone of the furnace. Electrically, this carbon is significantly more conductive than the other material in the reaction zone, and the accumulated carbon lowers the electrical conductivity of the reaction zone. If the electrodes are being controlled on resistance, then the controllers need to raise the electrodes in order to keep the overall resistance constant. This affects the mode of power dissipation in the reaction zone and the metallurgy.
  • the electrode length affects the magnetic field around the electrode, and hence the inductance associated with that electrode. Therefore, the measurement of the individual inductances should provide some indication of the lengths of the individual electrodes.
  • All arc furnaces need to slip fresh segments of electrodes regularly through the electrode clamps to make up for wear off the tip, and to control this properly requires some indication of the length of each electrode.
  • the tip With a submerged-arc furnace the tip is buried in the burden in the furnace and hence the electrode length is difficult to measure.
  • most submerged-arc furnaces use self-baking electrodes, also called S ⁇ derberg electrodes, which must be slipped in a controlled way regularly, in small amounts, and not irregularly in large and erratic jumps. Sometimes an operator of a furnace will burn down the burden, pull the electrodes up to top stops, and physically measure their lengths.
  • the operator tries to calculate or estimate the rate of wear off the tip, and then balance this against the rate of slipping, but the accuracy of this deteriorates with time. Otherwise there is no option but to monitor conditions around the furnace and try to adjust the slipping accordingly. If the furnace electrodes are not properly controlled on resistance, one electrode can end up considerably shorter or longer than anticipated. This will upset the metallurgy of the furnace, and can lead to the production of significant amounts of off-grade product material that has a lower market value.
  • US patent No. 6058134 to Toivonen describes a technique for finding circuit parameters in an arc furnace by solving various sets of equations that are derived for real power, reactive power and total power at various frequencies including the fundamental frequency.
  • Toivonen's technique is based on a frequency-domain approach wherein Fourier transforms are calculated and circuit parameters are then estimated in the frequency domain.
  • Toivonen's technique inter alia depends on the assumption that the inductance is the same at the mains frequency and at the harmonic frequencies. In fact the inductance can be substantially different because of the pseudo-reactive behaviour of a non-linear arc. Toivonen's approach has two further drawbacks.
  • the invention is concerned with a method of operating and controlling an arc furnace which at least partly addresses the aforementioned requirements, and the 5 drawbacks associated with existing controlling processes.
  • the invention provides a method of operating and controlling an arc furnace which has a plurality of electrodes connected to a polyphase power supply by means of at least one power transformer, the method including the steps of recursively ) estimating in real time values of parameters of circuit elements of an equivalent electrical circuit for the arc furnace in operation, and using the estimated parameter values to control at least part of the operation of the arc furnace.
  • the recursive estimation can be used to predict parameter values using information selected from the following: voltages applied to electrodes of the 5 furnaces; currents supplied to electrodes of the furnace; differentiated values, with respect to time, of currents supplied to electrodes of the furnaces; and the position of at least one tap changer on the at least one power transformer.
  • the differentiated values are produced by an analogue differentiation process or an equivalent process.
  • Measurements of the currents can be made on the primary or secondary side of the power transformer or at some intermediate point.
  • measurements of the voltages can be made on the primary or secondary side of the power transformer or at some intermediate point.
  • the power transformer may have its primary winding in a star configuration or in a delta configuration.
  • the parameters for which the values are predicted may be selected from: resistance of an electrode; inductance of an electrode; arc voltage of an electrode; the time constant of an arc; its residual conductivity; power per electrode; and fraction of the power per electrode that is dissipated in an arc.
  • phasor information can be determined from waveforms obtained through the method of the invention, phasor diagrams for the various currents and voltages can be plotted on a suitable display. These diagrams are potentially particularly useful inter alia for setting up and checking a controller which implements the method of the invention.
  • the estimated parameters can be used in various ways to control the operation of the furnace, for example to control electrode hoists transformer taps and the rate of slipping of each electrode and to adjust the composition or relative proportions of raw materials fed to the furnace particularly the ratio of carbon to reducible ores.
  • skewed secondary voltages are achieved by using different tap positions on the three phases, a practice which is known as differential tapping. It may be desirable to have skewed secondary voltages if a furnace is not well balanced. Differential tapping may be needed, for example, to lessen the relative amount of the negative-phase-sequence component in the power drawn from the mains, or to boost the current in one of the electrodes where otherwise the current would be particularly low.
  • This circulating current is undesirable in that it loads the transformers without delivering any currents to the electrodes, and hence the extent of differential tapping is usually relatively small. It is possible though to analyze a differential tapping situation by normal circuit analysis methods and determine what the currents and voltages are in the electrodes. The recursive estimating can then be done on these currents and voltages. Thus it falls within the scope of the invention to use the information produced by the recursive estimation to control the skewed voltages in an appropriate manner eg. to maintain a specific relationship between the voltages, or to take action to correct the skewed voltages.
  • Figure 1 is a schematic representation of apparatus used for implementing the method of the invention
  • Figure 2 illustrates an equivalent circuit of an arc furnace used in a time-domain model of the circuit, which forms the basis of the method of the invention
  • Figure 3 illustrates a structure of a digital filter for a three-electrode furnace
  • Figure 4 is a block diagram representation of a furnace control arrangement based on the apparatus of the invention cascaded with a Minstral-type controller which is at least partly based on the description in the specification of US patent No. 4296269.
  • parameters of circuit elements in an equivalent electrical circuit of an arc furnace are estimated from waveforms of the voltages and currents in the furnace.
  • the parameters typically include the resistance, inductance (or its reactance) and arc-related parameters such as arc voltage, in each limb of the circuit.
  • Apparatus 10 which implements the method of the invention, is shown schematically in Figure 1.
  • Analogue signals 12, 14 and 16 which respectively represent a set of currents in the high-power circuit of the furnace, transformer tap positions, and a set of voltages in the high-power circuit of the furnace, are fed through isolating and scaling amplifiers 18 to a unit 20 which contains a multiplexer and an analogue-to-digital converter (ADC).
  • Luu J4j i ne current signals rz are a.c. ana are typically trom U to 5 amps. I hey are normally obtained from the outputs of current transformers (not shown) that are located on the high-power lines.
  • the tap position signals 14 are direct current (d.c.) and are typically from 4 to 20 milli-amp d.c.
  • the tap position signals may be obtained in a digital form, using any appropriate device, e.g. a computer which may be the computer 26 referred to hereinafter.
  • the voltage signals 16 may be 110 volts a.c. They are normally obtained from the outputs of voltage transformers (not shown) that are located on the high- power lines.
  • a computer 22 runs a control program which causes the unit 20 to sample the waveforms and to present the sampled values to software in the computer 22.
  • the waveforms thus arrive as a succession of data sets, with each set being in the nature of a snap-shot set of the instantaneous values of each of the analogue signals, at the corresponding observation time.
  • the software in the computer 22 then converts these current and voltage waveforms into a set of data consisting of the currents flowing through the electrodes, designated /o, /i, and / 2 , and the voltages on the electrodes, designated VQ, V- ⁇ , and vfc.
  • this conversion requires information about the transformer tap ratios, use may be made of the transformer tap position signals to select the corresponding ratios from a table of such values.
  • circuit parameters is updated from each successive set of data, shortly after it arrives in the computer 22. As indicated in Figure 1 , these estimates of circuit parameters might, for example, be displayed for operator information 24, be sent through a data link to another computer 26, be logged to a disk file 28 for later use or analysis, or be used directly in the control 30 of the furnace.
  • the apparatus 10 is linked through some form of data communications line to a scada type of computer system for logging of real-time data from the plant, as well as for interacting with operators and other users.
  • Control signals which come either directly from the apparatus or from the scada system are routed through a programmable logic controller (PLC) or similar device, connected to the controller or scada. These signals are typically timed on/off signals for driving electrode hoists or electrode slippage controls, or analogue signals such as mass set points for a weighing-batching system to control the composition of raw materials fed to the furnace.
  • PLC programmable logic controller
  • the method of the invention uses a time-domain model of the furnace circuit which is based on the arrangement shown in Figure 2.
  • an arc 32, a resistor 34 and an inductance 36 are included in each branch of the star configuration and the phases are respectively numbered 0, 1 and 2.
  • a model of the arc which is based on multiple parameters as opposed to the single parameter/square wave model relied on by Toivonen, is preferably used in the method of the invention and, in the following example, a version of what is known as Cassie's model of the arc is used in the simulation which is carried out. This model was originally published by Cassie 1 and is well described in Brown 2 . Although it is preferred to make use of Cassie's arc model it is to be understood that this is by way of example only, and that any other satisfactory technique for modelling the arc could be used in the method of the invention.
  • Equation 1 can be rearranged as follows:
  • v A r c i is the voltage across the arc under electrode i (see Cassie's model), and the other symbols are as defined in Figure 2.
  • An arc is a non-linear circuit element, whose characteristics vaguely resemble those of a constant-voltage device.
  • the waveform of the voltage on an arc is thus more like a square wave than a sinusoid.
  • An arc model based on a square wave has only one parameter, and that is the magnitude of the wave.
  • a simple square wave was tried for the arc voltage waveform in each phase, but this exhibited a number of undesirable properties, mainly from the numerical integration side.
  • a version of Cassie's model was adopted which requires up to 3 parameters. It has been found that model works well, and that the additional parameters have some meaning in their own right in terms of the metallurgy of the furnace.
  • H ⁇ is the energy contained in the ionisation.
  • the first term on the right side, v ⁇ r c i-'i, ' s the electrical power being dissipated in the arc.
  • the second term on the right side is a linearisation of the relationship governing the rate of discharge of the arc.
  • the residual energy parameter H 0 ⁇ is normally small compared to Hi, and so, to a first approximation, the rate of discharge of the energy is proportional to the energy.
  • k ⁇ is a constant of proportionality.
  • Equations 3, 4 and 5 are the basic equations of the version of Cassie's model and with equation 2 are solved numerically using standard numerical integration techniques to simulate the evolution of the circuit with time.
  • the implementation of these equations in a computer program forms a software model of the electrical circuit of the arc furnace (referred to hereinafter as the software model 44).
  • Equation 6 shows that Cassie's model at steady state and without a residual energy term becomes a constant-voltage device.
  • Cassie's model produces a waveform for the arc voltage that looks like a distorted square wave. If an arc voltage parameter, v A rci, is defined as V(/ci//c2j), then the nominal magnitude of the distorted square wave will be approximately VA ⁇ CI -
  • a residual conductivity parameter, ⁇ O j is defined as k % .Ho ⁇ . From tests it appears that the residual conductivity parameter is strongly correlated with the temperature of the material in the reaction zone and in the furnace and that it may have a physical significance related to the metallurgy of the process.
  • the parameter Zc 1 ⁇ can be replaced by 1/TJ, where ⁇ ⁇ is the time constant for the
  • this discharge time constant is much like the RC time constant for the discharge of a resistor-capacitor circuit. From results obtained from the recursive estimator this discharge time constant for an arc
  • the recursive estimation is done using a digital filter which is shown in block diagram form in Figure 3.
  • Derived parameters such as the power consumed by each electrode, and the fraction of this power for each electrode that is dissipated in its arc, may also be generated simultaneously.
  • the digital filter operates in a cyclic fashion in real time, performing one iteration each time a snap-shot set of observations of the waveforms is brought in from the analogue-to-digital converter in the unit 20, as opposed to an estimator that is run in a batch mode.
  • the term "Kalman filter” is also used. An explanation of digital filters can be found in Jazwinksi 3 and Bozic 4 .
  • FIG 3 The equivalent circuit of this power circuit is the circuit depicted in Figure 2.
  • the actual voltages 45 are supplied to the furnace electrodes. Signals corresponding to these voltages, which are designated V 0 , y-i, and V 2 , derived through the measurement system shown in Figure 1 , are also fed into the digital filter as the vector of inputs 42 to the software model 44 of the electrical circuit (see Figure 3).
  • the power circuit 40 of the furnace responds to the applied voltages by allowing a current to flow through each electrode.
  • These currents and their derivatives form a set (denoted by a vector Y 2 ) of actual signals.
  • the software model 44 in response to the sampled furnace electrode voltages 45, and in conjunction with the current values of the predicted means of the circuit parameters 54, generates a vector Y p of predicted mean values of the electrode currents and the derivatives thereof (block 48).
  • An adjustment algorithm 52 operates on these differences ⁇ Y to modify the predicted means of the circuit parameters 54. This continually-updated vector of parameters is then outputted as the estimates from the filter.
  • the a.c. current signals from the arc furnace supply can be obtained from standard current transformers on the high-tension primary lines or on intermediate transformer windings, however, a related signal could be obtained from a Rogowski coil, which could be located around any of the current conductors, including the secondary busbars or even the electrodes themselves.
  • a Rogowski coil is a core- less helical coil arranged in a loop around a conductor that carries the a.c. current, and the signal is derived from the voltage induced in this helical coil (unlike a normal current transformer where a current is induced to flow in the secondary winding to oppose the magnetic field induced by the current in the main conductor).
  • the voltage picked up by the Rogowski coil is proportional to di/dt in the main conductor.
  • a reference herein to a di/dt signal is intended to include a signal of this type which is produced without directly implementing an analogue differentiating process on the current signal.
  • the parameters which are predicted (block 54) through the use of the adjustment algorithm are used to provide visible information and loggable data on the functioning of the arc furnace, and to control the arc furnace either to achieve a more effective operation or to achieve a desired end product.
  • the aspects of data display and storage (24, 28) and the step 30 of furnace control, shown in Figure 1 are collectively designated in a block labelled 24, 28 and 30 in Figure 3.
  • the predicted parameters can be used to control at least the following: the electrode hoists, the slipping of each electrode, carbon balance and metal grade, and electrical aspects including transformer tap positions.
  • the recursive process provides estimates of the resistance and reactance per electrode, and of derived variables, such as the power per electrode.
  • the electrode hoists can be controlled automatically in response to these estimated values, using a suitable algorithm.
  • the inductance in each phase of the circuit is an indication of the length of the corresponding electrode, but the apparatus can take a relatively long time (of the order of hours to days) to estimate these inductances adequately. It is possible to apply a simple control loop between the estimated inductance and the rate of slipping, but this may be too coarse an approach. Instead use is made of an "electrode management system", in which graphical trends get displayed to a human operator, who alters the rate of slipping accordingly.
  • the inductance information and electrode length information are matched using software or by eye. For each electrode an electrode length equivalent of its inductance is plotted and an electrode length signal is then calculated as a function of time, by subtracting the accumulated erosion from the accumulated slip. This is then plotted on the same graph. The operator then moves the plots (on a computer system by "dragging" the plots with a mouse) to get a reasonable fit between them. The software accommodates this by adjusting the rate of erosion per MWh, or by changing the zero point of the conversion between reactance and length. If a spot reading of an actual electrode length becomes available (e.g. by burning down and measuring the length), then this can be added as a reference point on the corresponding graph.
  • Ongoing estimates of the electrode length can be obtained from the graph.
  • the accuracy of such an estimate is typically of the order of 200 to 300 mm.
  • the carbon/reductant balance can be directly controlled by automatically selecting recipe set points on a weighing-batching system, or indirectly, through an intermittent, off-line scheme in which, in response to information from the apparatus, a decision is made on the usage of raw materials which are then manually entered into an automatic batching system for feeding the furnace.
  • the rate of change in the carbon inventory in the furnace is the difference between the addition of fresh carbon and its consumption by the reactions in the process. There may also be a small loss of carbon, firstly through material that gets washed out of the taphole unreacted and, secondly, through burnoff from the surface of the burden. In the absence of some abnormal upset, like a batching system malfunction, the carbon inventory normally takes of the order of several hours to get badly out of balance.
  • Part or all of the information for the carbon balance can be based on the estimates of the parameters from the control apparatus, particularly those parameters which are related directly to the arc behaviour, viz. arc voltage, residual conductivity, and discharge time constant. Other information could also be used, such as intermittent analyses of the product material coming from the furnace.
  • the carbon balance in the furnace is dependent on the general mass and heat balance for the furnace.
  • a prior offline study of the process must be undertaken to generate one or more functions, using a technique such as multi-linear regression or neural-net analysis, relating the relative amount of carbon in the furnace to the estimated parameters from the control apparatus and, possibly, to information from other sources.
  • Control can thus be exerted over the relative amount of arcing. This affects the temperature in the reaction zone and so enables the %Si in the end product to be controlled. It is believed that similar results can be achieved with this technique in respect of other constituents.
  • Ferro-alloy processes are conventionally categorised as “wet” or “dry”, depending on whether slag is normally present inside the furnace or not. Silicon and ferro-silicon furnaces are categorised as dry, while ferro-chrome and ferro- manganese furnaces are categorised as wet.
  • Parameters produced by the apparatus of the invention are noisy and relatively slow to respond ( ⁇ 3 to 10 seconds) to changes in furnace conditions. It is better to use a Minstral-type control system for direct control of the furnace and, then in a cascade arrangement, to use the parameters to manipulate the set points of the
  • Minstral-type control loops This allows for control of the electrode resistances and power levels, through manipulation of the electrode hoists and transformer tap changers, and has the advantage that the response is fast and direct, and therefore
  • Figure 4 shows ' a typical layout of a cascade control scheme wherein a slave loop is represented by a secondary controller such as a Minstral controller 70, actuators 72 for electrode hoists and transformer tap changers, the power circuit of the furnace 40 and the electrical signals 76 for the Minstral controller, which is known per se in the art.
  • a master control loop is represented by a.c. measured signals 78, the parameters 54 produced in accordance with the techniques described hereinbefore, a mapping algorithm 84, and resistance set points 86 to the controller 70.
  • Minstral controller's response is to tap down the transformer voltages. This may lead to lower power levels which adversely affect production and hence, in creating this cascade structure, such limits need to be carefully accommodated. This may be achieved by adjusting the outputs of the mapping algorithm 84.
  • the mapping algorithm 84 allows for various options. For example, one can use as input either the arc voltage vxrci, or the burden resistance R 1 , or a combination thereof.
  • the form of the mapping can be selected at least from the following techniques:
  • mapping algorithm is as follows: take R 1 , smooth it using a digital smoothing filter, add an offset, limit this within a band, and pass the result as a set point to the Minstral resistance controller.
  • v ⁇ rci, or R 1 can be used (though the gain will be different for the two cases) as an input to the mapping.
  • the input is then passed through a conventional PID (Proportional, Integral, Derivative) controller to generate the Minstral set point.
  • PID Proportional, Integral, Derivative
  • the output of the mapping is then subjected to the same constraints as in Technique 1.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Discharge Heating (AREA)
  • Furnace Details (AREA)

Abstract

La présente invention concerne un procédé de commande de four à arc électrique utilisant un estimateur récursif pour évaluer, en temps réel, les paramètres d'un circuit électrique équivalent du four, ces paramètres évalués servant à la commande de fonctionnement du circuit.
PCT/ZA2006/000024 2005-02-20 2006-02-14 Commande de four a arc electrique Ceased WO2006089315A1 (fr)

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ZA2004/9190 2005-02-20

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Cited By (6)

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EP2362710A1 (fr) * 2010-02-23 2011-08-31 Siemens Aktiengesellschaft Procédé de fonctionnement d'un four à arc, dispositif de commande et/ou de réglage pour un four à arc et four à arc
RU2556698C1 (ru) * 2013-12-30 2015-07-20 Общество с ограниченной ответственностью "Объединенная Компания РУСАЛ Инженерно-технологический центр" Способ и система управления электротехнологическими режимами восстановительной плавки технического кремния в руднотермических электрических печах
WO2016183672A1 (fr) 2015-05-15 2016-11-24 Hatch Ltd. Procédé et appareil de mesure de la longueur d'une électrode dans un four à arc électrique
US11096251B2 (en) * 2017-11-08 2021-08-17 Northeastern University Calculation method for operating resistance in dual-electrode dc electric-smelting furnace for magnesium
CN114861414A (zh) * 2022-04-20 2022-08-05 厦门理工学院 一种改进阻抗电弧模型的建立方法、装置、设备及其介质
CN115640656A (zh) * 2022-10-26 2023-01-24 中盐吉兰泰氯碱化工有限公司 一种电石炉炉型设计方法

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WO2011104071A1 (fr) * 2010-02-23 2011-09-01 Siemens Aktiengesellschaft Procédé permettant de faire fonctionner un four à arc électrique, dispositif de commande et/ou de régulation d'un four à arc électrique et four à arc électrique
CN102771183A (zh) * 2010-02-23 2012-11-07 西门子公司 用于运行电弧炉的方法，用于电弧炉的控制和/或调节装置和电弧炉
RU2514735C1 (ru) * 2010-02-23 2014-05-10 Сименс Акциенгезелльшафт Способ эксплуатации электродуговой печи, устройство управления и/или регулирования для электродуговой печи и электродуговая печь
CN102771183B (zh) * 2010-02-23 2014-07-16 西门子公司 用于运行电弧炉的方法，用于电弧炉的控制和/或调节装置和电弧炉
RU2556698C1 (ru) * 2013-12-30 2015-07-20 Общество с ограниченной ответственностью "Объединенная Компания РУСАЛ Инженерно-технологический центр" Способ и система управления электротехнологическими режимами восстановительной плавки технического кремния в руднотермических электрических печах
WO2016183672A1 (fr) 2015-05-15 2016-11-24 Hatch Ltd. Procédé et appareil de mesure de la longueur d'une électrode dans un four à arc électrique
US11096251B2 (en) * 2017-11-08 2021-08-17 Northeastern University Calculation method for operating resistance in dual-electrode dc electric-smelting furnace for magnesium
CN114861414A (zh) * 2022-04-20 2022-08-05 厦门理工学院 一种改进阻抗电弧模型的建立方法、装置、设备及其介质
CN115640656A (zh) * 2022-10-26 2023-01-24 中盐吉兰泰氯碱化工有限公司 一种电石炉炉型设计方法

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