SU921123A1

SU921123A1 - Method and device for automatic regulating of electric mode of multi-phase electric arc furnace

Info

Publication number: SU921123A1
Application number: SU802949999A
Authority: SU
Inventors: Борис Петрович Полков; Юрий Николаевич Игнатьев; Николай Иванович Фомкин; Василий Евдокимович Козлов
Priority date: 1980-07-03
Filing date: 1980-07-03
Publication date: 1982-04-15

Description

Изобретение относится к электротермии и может быть использовано в автоматическом регулировании электрического режима дуговых электропечей.The invention relates to electrothermics and can be used in automatic regulation of the electric mode of electric arc furnaces.

Известен способ автоматического ⁵регулирования электрического режима дуговой электропечи путем перемещения электродов в зависимости от отклонения регулируемых величин и воздейст₁₀вия на основной канал регулирования корректирующим сигналом, формируемым при оптимизации электрического параметра,' характеризующего режим печи, при котором в качестве оптимизируе- ₁₅мого параметра используют сумму дисперсий действующих значений токов друг отдельных фаз печи, указанный корректирующий сигнал формируют при минимизации этой суммы, а его воз- _мдействием на основной канал регулирования изменяют параметры отдельных статических и динамических звеньев этого канала [1] . ⁵ a known method of automatic regulation of the electric arc furnace by moving the electrode mode depending on the deviations of controlled variables and vozdeyst Via ₁₀ on main control channel correction signal generated in the optimization of the electrical parameter 'characterizes the oven mode in which as a direct parameter optimizirue- ₁₅ using the sum of the variances of the current values of the currents of each of the individual phases of the furnace, the specified correction signal is formed while minimizing this amount, and its z- _m action on the main control channel change parameters of selected static and dynamic elements of the channel [1].

Недостатком известного способа является отсутствие возможности форсированной отработки отдельных возмущений, возникающих, например, при обвалах шихты.The disadvantage of this method is the lack of the possibility of forced development of individual perturbations that occur, for example, when the collapse of the charge.

Наиболее близким к предлагаемому является способ автоматического регулирования электрического режима многофазной дуговой электропечи, при котором во время плавки поддерживают заданное значение мощности путем измерения тока электрода в каждой фазе, сравнения его с\тремя различными заданными уровнями.и перемещения электродов при наличии сигнала рассогласования, на скорости, соответствующей каждому уровню до устранения сигнала рассогласования, фиксируют, момент начала вскипания шлака и снижают мощность печи до минимально допустимой, например снижением токов электродов, выдерживают этр значение мощности заданное время и затем вновь после окончания кипения шлакаClosest to the proposed one is a method for automatically controlling the electric mode of a multiphase arc electric furnace, during which a set power value is maintained during melting by measuring the electrode current in each phase, comparing it with three different set levels, and moving the electrodes in the presence of a mismatch signal at a speed corresponding to each level until the mismatch signal is eliminated, the moment of slag boiling start is fixed and the furnace power is reduced to the minimum allowable, for example, by lowering the currents of the electrodes, the etre power value is maintained for a predetermined time and then again after the end of boiling of slag

9211 повышают мощность до ранее поддерживаемого значения [2} .9211 increase power to a previously supported value [2}.

Устройство для осуществления этого способа содержит в каждой фазе датчик тока, подключенный к первому входу блока сравнения, второй вход которого соединен с задатчиком тока, а выход - со входами трех пороговых элементов с различными зонами нечувствительности, выходы'которых подключены ко входам блока регулирования, связанного выходом со входами блоков перемещения электрода.A device for implementing this method comprises, in each phase, a current sensor connected to the first input of the comparison unit, the second input of which is connected to the current detector, and the output to the inputs of three threshold elements with different dead zones, the outputs of which are connected to the inputs of the control unit connected an exit with inputs of blocks of movement of an electrode.

Недостатком известного способа является то, что момент вскипания шлака определяется оператором визуально, что иногда приводит к аварийным ситуациям и, значит, к снижению надежности работы.The disadvantage of this method is that the moment of boiling up of slag is determined visually by the operator, which sometimes leads to emergency situations and, therefore, to a decrease in reliability.

Целью изобретения является устранение указанных недостатков.The aim of the invention is to remedy these disadvantages.

Для достижения этой цели момент начала вскипания шлака определяют по превышению заданного значения частоты одновременного наличия сигналов рассогласования токов среднего уровня всех фаз.To achieve this goal, the moment the slag begins to boil is determined by exceeding a predetermined frequency value of the simultaneous presence of mismatch signals of currents of the average level of all phases.

Для осуществления этого известное устройство снабжено элементом совпадения, входы которого связаны с выходами всех пороговых элементов средней зоны нечувствительности,а выход-с шиной сложения реверсивного счетчика,ши на вычитания которого подключена к выходу генератора, первый выход - к первому входу исполнительного блока задатчика тока всех фаз, а второй - ко входу нуль-органа, связанного первым выходом со вторым входом исполнительного блока, а вторым - со входом генератора.To accomplish this, the known device is equipped with a coincidence element, the inputs of which are connected to the outputs of all threshold elements of the middle deadband, and the output is connected to the addition bus of a reversible counter, whose subtraction is connected to the generator output, the first output to the first input of the actuator phases, and the second to the input of the null-organ connected with the first output with the second input of the executive unit, and the second with the input of the generator.

На чертеже изображена блок-схема устройства.The drawing shows a block diagram of a device.

Указанное устройство содержит датчик тока 1, блок сравнения 2, задатчик тока 3» блок пороговых элементов .минимальной зоны нечувствительности 4, средней зоны нечувствительности 5 и максимальной зоны нечувствительности 6, блок регулирования 7, блоки управления перемещением электрода 8 и 9» элемент совпадения 10, реверсивный счетчик 11, исполнительный блок 12, нуль-орган 13 и генератор 14, ширину сложения 15 реверсивного счетчика, шину¹ вычитания 16.The specified device includes a current sensor 1, a comparison unit 2, a current controller 3 "block of threshold elements. Minimum dead zone 4, middle dead zone 5 and maximum dead zone 6, control unit 7, control units for moving the electrode 8 and 9" coincidence element 10, reversible counter 11, actuating unit 12, null-organ 13 and generator 14, addition width 15 of the reversible counter, subtraction bus ¹ .

Устройство работает следующим образом.The device operates as follows.

44

Сигнал с выхода.датчика тока 1 сравнивается с сигналом задатчика тока ,3 на блоке сравнения 2. С выхода блока сравнения 2 сигнал рассогласова, ния поступает на входы пороговых элементов минимальной зоны нечувствительности 4, средней зоны нечувствительности 5 и максимальной зоны нечувствительности 6. В зависимости от велиI чины рассогласования между током фазы и сигналом задатчика тока 3 будет срабатывать тот или другой пороговый элемент. Сигналы с выходов пороговых элементов зоны нечувствительности i 4-6 поступают на входы блока регулирования 7, который вырабатывает сигналы блокам управления перемещением электрода 8 и 9· На вход элемента совпадения 10 поступают сигналы с выходов ) пороговых элементов средней зоны нечувствительности 5 всех трех фаз, а с выхода элемента совпадения 10 - на шину сложения 15 реверсивного счетчика 11. При переполнении реверсив;! ный счетчик 11 вырабатывает сигнал исполнительному блоку 12 на срабатывание. Исполнительный блок 12 управляет задатчиками тока 3 всех трех фаз. Нуль-орган 13, связанный со вто₍ рым выходом реверсивного счетчика 11, служит для фиксации нулевого состояния счётчика и вырабатывает сигналы на отключение исполнительного блока 12 и генератора 14. С выхода генератора 14, в свою очередь, импульсы за~ ’ данной.частоты поступают на шину вычитания 16 реверсивного счетчика 11. Начало ’вскипания шлака в электропечи характеризуется быстрым поднятием уровня расплава и, следователь¹ но, значительным отклонением фазного тока от заданного значения. При этом происходит частое срабатывание канала второй скорости,а именно порогового элемента средней зоны нечувствительности 5· Увеличение частоты срабатывания канала второй скорости и положено в основу определения момента начала вскипания шлака. Сигналы с выходов пороговых элементов сред¹ ней зоны нечувствительности 5 всех трех фаз поступают на входы элемента ύ совпадения 10, к выходу которого подключена шина сложения 15 реверсивного счетчика 11. В исходном состоянии . реверсивный счетчик 11 находится в нулевом состоянии, исполнительный блок 12 отключен. С нуль-органа 13 на генератор 14 поступает сигнал запрета, в результате чего он находится в отключенном состоянии.The signal from the output of current sensor 1 is compared with the signal of the current setter, 3 on the comparison unit 2. From the output of the comparison unit 2, the mismatch signal is fed to the inputs of the threshold elements of the minimum dead band 4, middle dead band 5 and maximum dead band 6. Depending depending on the mismatch between the phase current and the signal of the current setter 3, one or another threshold element will be triggered. The signals from the outputs of the threshold elements of the dead zone i 4-6 are fed to the inputs of the control unit 7, which generates signals to the control units for the movement of the electrode 8 and 9. The input from the coincidence element 10 receives signals from the outputs of the threshold elements of the middle dead zone 5 of all three phases, and from the output of the coincidence element 10 - to the addition bus 15 of the reverse counter 11. When overflowing reverse ;! the current counter 11 generates a signal to the Executive unit 12 to operate. The Executive unit 12 controls the current settings 3 of all three phases. The null-organ 13 associated with the second ₍ second output of the reverse counter 11) serves to fix the zero state of the counter and generates signals to turn off the executive unit 12 and generator 14. From the output of the generator 14, in turn, pulses for ~ 'the given frequency arrive bus 16 to the subtractor 11. The down counter Start 'boiling in the electric furnace slag characterized by a rapid raising of the melt level, and consequently ^one but a significant deviation of the phase current of a predetermined value. Thus there is a frequent operation of the second channel ch growth, namely the threshold element average deadband 5 · Increased channel response frequency is the second speed, and as the basis for determining the start of boiling of the slag. The signals from the outputs of threshold elements media ¹ therein deadband 5 all three phases to the inputs ύ matching element 10, the output of which is connected to the addition bus 15 of the reverse counter 11. In the initial state, the reverse counter 11 is in the zero state, the Executive unit 12 is disabled. From the zero-organ 13 to the generator 14 receives a prohibition signal, as a result of which it is in the off state.

Момент начала вскипания шлака сопровождается срабатыванием блоков пороговых элементов средней зоны нечувствительности 5 одновременно всех трех фаз. Элемент совпадения 10 при этом начинает срабатывать, и импульсы с его выхода поступают на шину сложения 15 реверсивного счетчика 1 1. Как только реверсивный счетчик 11 выйдет из нулевого состояния, сигнал на входе нуль-органа 13 исчезает. Также исчезает и сигнал запрета со входа генератора 14. С генератора 14 начинают поступать импульсы на шину · вычитания 16 реверсивного счетчика 11. Частота импульсов генератора 14 подбирается таким образом,.чтобы она, была на порядок ниже частоты срабатывания каналов второй скорости в период вскипания шлака, т.е. частоты выходных импульсов элемента совпадения 10.The moment the slag begins to boil is accompanied by the triggering of blocks of threshold elements of the middle dead zone 5 simultaneously of all three phases. In this case, coincidence element 10 starts to operate, and pulses from its output go to addition bus 15 of the reverse counter 1 1. As soon as the reverse counter 11 leaves the zero state, the signal at the input of the null organ 13 disappears. The inhibit signal also disappears from the input of the generator 14. From the generator 14, pulses begin to arrive on the bus · subtracting 16 of the reverse counter 11. The pulse frequency of the generator 14 is selected in such a way that it is an order of magnitude lower than the response frequency of the channels of the second speed during the boiling period of slag , i.e. frequency of the output pulses of the coincidence element 10.

Таким образом, в начальной стадии _;периода вскипания шлака реверсивный счетчик .11 переполнится и на его выходе, подключенном к одному из входов 'исполнительного органа 12, появится сигнал. С появлением указанного _{s ;}сигнала исполнительный орган 12 срабатывает и воздействует на задатчики 3 всех трех фаз, в результате чего величина задания Фазных токов уменьшается до своего минимального значения. Мощность, вводимая в электропечь, значительно снижается, а перемещения электродов, в результате работы системы автоматического регулирования, будут способствовать скорейшему выходу наружу реакционных газов, поднимающих расплав. Таким образом, про· цесс кипения шлака будет постепенно спадать, и частота срабатывания каналов второй скорости, соответственно, уменьшаеться. Спустя некоторое время, зависящее от частоты импульсов генератора 14, частота срабатывания канала второй скорости станет меньше частоты импульсов генератора 14. Реверсивный счетчик 11 будет ра- ^;ботатъ на вычитание. И как только реверсивный счетчик 11 вернется в нулевое состояние, сработает нуль- ; орган 13· Последний отключит генератор 14 и исполнительный блок 1-2, ко- ^!торый, в свою очередь, воздействуя на задатчики 3 всех фаз восстановит номинальные величины,задания тока, т.е.Thus, in the initial stage _; of the slag boiling period, the reversible counter .11 will overflow and a signal will appear at its output connected to one of the inputs of the executive body 12. With the advent of the specified _s; of the signal, the actuator 12 is activated and acts on the settings 3 of all three phases, as a result of which the value of the Phase currents task decreases to its minimum value. The power introduced into the electric furnace is significantly reduced, and the movement of the electrodes, as a result of the operation of the automatic control system, will contribute to the rapid exit of the reaction gases that raise the melt. Thus, the boiling process of the slag will gradually decrease, and the response frequency of the second-speed channels will accordingly decrease. After some time, depending on the frequency of the pulses of the generator 14, the response frequency of the channel of the second speed will become less than the frequency of the pulses of the generator 14. The reverse counter 11 will be ^; subtraction bot. And as soon as the reverse counter 11 returns to the zero state, zero will work; body 13 · The latter will turn off the generator 14 and the Executive unit 1-2, what- ^! which, in turn, acting on the settings 3 of all phases will restore the nominal values, the current settings, i.e.

1123 6 восстановится номинальный электричес· кий режим работы электропечи.1123 6 the nominal electric mode of operation of the electric furnace is restored.

Использование предлагаемого изобретения позволит предотвратить ава5 рийные ситуации за счет автоматической фиксации начала вскипания и снижения вводимой в электропечь мощности,. что, в конечном счете, приведет к повышению технико-экономических ю показателей работы электропечи.The use of the present invention will prevent emergency situations due to automatic fixation of the beginning of boiling and reduction of the power introduced into the electric furnace. which, ultimately, will lead to an increase in the technical and economic indicators of the electric furnace.

Claims

The invention relates to electrotherapy and can be used in the automatic regulation of the electric mode of electric arc furnaces. There is a known method of automatic control of the electric mode of an electric arc furnace by moving the electrodes depending on the disconnection of the controlled values and the effect on the main control channel with a correction signal generated during the optimization of the electrical parameter characterizing the furnace mode, in which the sum of the dispersions of the effective values is used as the optimized parameter the currents of each of the individual phases of the furnace, the specified correction signal is formed while minimizing this amount, and its effect By changing the parameters of the individual static and dynamic links of this channel 1 to the main channel of adjustment. The disadvantage of this method is the lack of the possibility of forced testing of individual disturbances that occur, for example, during charge collapses. The closest 4 m to the present invention is a method for automatically regulating the electric mode of a multi-phase electric arc furnace, in which during a melting process a given power level is maintained by measuring the electrode current in each phase, comparing it with three different predetermined levels. And moving the electrodes in the presence of an error signal, at the speed corresponding to each input to eliminate the error signal, fix. the moment the slag starts to boil up and the furnace capacity is reduced to the minimum allowable, for example by reducing electrode currents, the power is maintained for a specified time and then again after the boiling 39 ends, the power is increased to the previously maintained value 2). A device for carrying out this method contains in each phase a current sensor connected to the first input of the comparison unit, the second input of which is connected to the current setting device, and the output to the inputs of three threshold elements with different dead zones, the outputs of which are connected to the inputs of the control unit connected an exit with inputs of blocks of movement of an electrode. The disadvantage of the known method is that the moment of slag boiling is determined visually by the operator, which sometimes leads to HbJM accidents and, therefore, to a decrease in reliability of operation. The aim of the invention is to eliminate these drawbacks. To achieve this goal, the moment of the start of slag boiling is determined by exceeding the set value of the frequency of the simultaneous presence of current error signals of the average level of all phases. To accomplish this, the known device is equipped with a coincidence element, the inputs of which are connected to the outputs of all threshold elements of the middle deadband, and the output to the folding bus of the reversible counter, the subtractor's bus width to the output of the generator, the first output to the first input of the execution unit setting the current of all phases, and the second to the input of the zero-organ connected by the first output to the second input of the executive unit, and the second to the input of the generator. The drawing shows a block diagram of the device. The specified device contains a current sensor 1, a comparison unit 2, a current setting device 3, a block of threshold elements k of the minimum deadband k, a middle deadband 5 and a maximum deadband 6, the control block 7, the control units for moving the electrode 8 and 9, the coincidence element 10 , a reversible counter 11, an executive unit 12, a zero-body 13 and a generator k, the width of the addition 15 of a reversing counter, a subtraction bus 16. The device works as follows. 34 The signal from the output of current sensor 1 is compared with the signal of the current setting device 3 on the comparison block 2. From the output of the comparison block 2, the error signal goes to the inputs of the threshold elements of the minimum deadband 4, the middle dead zone 5 and the maximum dead zone 6. In depending on the magnitude of the mismatch between the phase current and the signal of the current generator 3, one or another threshold element will operate. The signals from the outputs of the threshold elements of the dead zone arrive at the inputs of the control unit 7, which processes signals to the control units of the electrode 8 and 9 movement. The input of the coincidence element 10 receives signals from the outputs of the threshold elements of the middle dead zone 5 of all three phases, and from the output of the coincidence element 10 - to the addition bus 15 of the reversible counter 11. When overflow occurs, the reversible counter 11 generates a signal to the executive unit 12 to operate. Executive unit 12 controls the current setting devices 3 of all three phases. The null organ 13 associated with the second output of the reversible counter 11 serves to fix the zero state of the counter and generates signals to shut down the executive unit 12 and the generator 1. From the output of the generator 1, in turn, the pulses of a given frequency go to the subtraction bus 16 of the reversible counter 11. The start of slag boiling in an electric furnace is characterized by a rapid rise in the level of the melt and, therefore, a significant deviation of the phase current from the predetermined value. In this case, the second speed channel is frequently triggered, namely, the threshold element of the middle dead zone 3. An increase in the frequency response of the second speed channel is used as the basis for determining the start of slag boiling. The signals from the outputs of the threshold elements of the middle dead zone 5 of all three phases are fed to the inputs of the coincidence element 10, the output of which is connected to the fold 15 of the reversible counter 11. In the initial state. the reversible counter 11 is in the zero state, the execution unit 12 is turned off. From the null organ 13 a signal is transmitted to the generator, as a result of which it is in the disconnected state. The moment of the start of slag boiling is accompanied by the operation of blocks of threshold elements of the middle dead zone 5 at the same time of all three phases. At this, the coincidence element 10 starts to operate, and the pulses from its output arrive at the addition bus 15 of the reversible counter 11. As soon as the reversible counter 1 goes out of the zero state, the signal at the input of the zero-body 13 disappears. generator input} TS. From generator 1, pulses are fed to the subtraction bus 16 of the reversible counter 11. The frequency of the pulses of generator I is selected in such a way that it is an order of magnitude lower than the frequency of operation of channels of the second speed during the slag boiling, i.e. the frequency of the output pulses of the coincidence element 10. Tpkim, in the initial stage of the slag boiling period, the reversible counter .11 overflows at its output, connected to one of the inputs of the actuator 12, on the signal. With the occurrence of this signal, the actuator 12 triggers and acts on the setters 3 of all three phases, as a result of which the setting value of the Phase currents decreases to its minimum value. The power introduced into the electric furnace is significantly reduced, and the displacement of the electrodes, as a result of the operation of the automatic control system, will facilitate the rapid exit to the outside of the reaction gases raising the melt. Thus, the slag boiling process will gradually decrease, and the response rate of the second-speed channels, respectively, will decrease. After some time, depending on the frequency of the generator pulses k, the response frequency of the channel of the second speed will become less than the frequency of the generator 1 pulses. Reversible counter 11 will work for subtraction. And as soon as the reversible counter 11 returns to the zero state, a zero is activated; authority 13- The latter will turn off the generator 1 + and the executive unit 1-2, which, in turn, will affect n. setting devices of 3 all phases will restore the nominal values of the current setting, i.e., 236 the nominal electric operating mode of the electric furnace will be restored. The use of the proposed invention will prevent emergencies by automatically fixing the start of boiling up and reducing the power input to the electric furnace, which ultimately leads to an increase in the technical and economic performance of the electric furnace. Invention Formula. t 1. A method of automatically adjusting the electric mode of a multi-phase electric arc furnace, in which during a melting process a given power value is maintained by measuring the electrode current in each phase, comparing it with three different predetermined levels and displacing the electrodes in the presence of an error signal at a speed corresponding to each level , before elimination of the error signal, fix the moment of the start of boiling up - slag and reduce / the furnace power to the minimum permissible, for example, by reducing the current of the electrodes in, maintain this power value for a predetermined time and then increase the power again to a previously maintained value, characterized in that, in order to increase the reliability of the furnace, the slag boiling start time is determined by exceeding the set value of the frequency of the simultaneous presence of current error signals. ovens.

2. A device for carrying out the method according to claim 1, comprising in each phase a current sensor connected to the first input of the comparison unit, the second input of which is connected to the current sensor and the output to the inputs of three threshold elements with different dead zones, the outputs of which are connected to the inputs of the control unit associated with the output from the inputs of the blocks for moving the electrode of the phase are distinguished by the fact that it is equipped with a coincidence element, the inputs of which are connected to the outputs of all the threshold elements of the middle deadband - a down counter ply tire, the tire which subtractor is connected to the generator output, the first output - to the first input of the execution unit

7 92P23 8

knob current of all phases, and the second -1. USSR author's certificate to the entrance of the null organ, related per-№ 289082, кп. H 05B 7/18, 19b5. output with the second input of the executive unit, and the second with input 2. Electrical equipment and automatic generator .5 ka electrothermal installations. Sources of information. Reference. M., EneEzgi, 1978 taken into account during examination, p. 2b5-2b8.