SU873474A1 - Device for regulating electric mode of three-phase ore-melting electric furnace with non-conductive hearth - Google Patents

Description

(54)

DEVICE FOR REGULATION OF ELECTRIC REGIME THREE-PHASE ORE-THERMAL ELECTRIC SAFETY WITH NON-CONDUCTING BODY

The invention relates to an electrotermine, and more specifically to the automatic regulation of the electrical power of ore-thermal furnaces with a non-conductive hearth or any other electrode furnaces with a non-conductive or low-conductive hearth. Devices are known for regulating the electric mode of a three-phase ore-thermal electric furnace with a non-conductive hearth, containing an arc sensor and a unit for calculating the voltage connected to two inputs of the comparator unit, the third input of which is connected to the reference unit, and the output to the displacement motor. electrode tlj and 12, the disadvantage of these devices is the low control accuracy. The purpose of the invention is to improve the accuracy of regulation. The goal is achieved in that the arc voltage detection unit is connected to a linear voltage sensor whose output is connected to the first input of the multiplication element, its second input is connected to the output of the sine calculation element connected to the input of the algebraic addition element, the first input of which is black the change in sign is connected to the sensor of the phase angle between the voltage and the current of the phase, its second input is to the sensor of the angle of the shift between the currents of the given and lagging phases, the output of the multiplication element is connected to the first the input of the second element of algebraic addition, the second input of which through the second element of the sign change is connected to the output of the second multiplication element connected by the first input through the second sine calculation element to the sensor of the phase angle between the currents of the given and lagging phases, and the second input to the output the third multiplication element, the inputs of which are connected to the arc current sensor of this phase and the input element of the active resistance parameter of this phase — the third input of the second element of the algebraic outlet is connected to you the fourth, the multiplication element, the first input of which through the cosine calculation element is connected to the phase angle sensor between the currents of the given and lagging phases, and the second input - to the output of the fifth multiplication element connected by the inputs to the current phase sensor and the parameter input element inductive resistance of this phase, the fourth input of the second element of algebraic addition through the third element of the sign change is connected to the output of the sixth multiplication element connected by inputs to the lagging phase current sensor and electric input input parameter of inductance resistance of the lagging phase, the output of the second element of algebraic addition is connected to the first input of the division element, the second input of which is connected to the output of the second sine calculation element, and its output serves as an output of the arc voltage detecting unit , ore-smelting furnace mode with non-conductive hearth. Voltages on arcs in the normal burning mode of three or two arcs are expressed by the following formulas V .VAvS () -Ib-Id siv in IAHdCo ". where A, B, C, are output terminals of the supply transformer; -inductive resistances of phase A, B, C; IA, Hz, If- - currents of the arcs of three phases; ir, g, g - active resistances of phases A, B, C; V, V, V are the linear voltages AV A and the sun output terminals of the supply transfermator; .. If- is the phase angle of the vector ig relative to TD; Ifj. - phase angle of the vector if. relatively Gd; lf.- phase angle VA relative to 1dg tfj-d- phase angle D / rdOt relatively Gd. A device for controlling the electric mode of a ore-smelting furnace with a non-conductive hearth contains in the control circuit of each phase a linear voltage sensor at the output of the presses of the supply transformer 1, an arc current sensor of an adjustable phase, a lagging phase arc current sensor 3, phase 4 of the phase angle between linear voltage at the terminals of the power supply tr. of the formator and the arc current is adjustable by phase, the sensor 5 of the phase angle between the arc current of the lagging phase and the arc current of the adjustable phase, two blocks of calculation of sine 6 and 7, a block in cosine 8 studies, six blocks of multiplication 9-14, two blocks of algebraic addition 15 and 16, three blocks for changing the sign 17-19, an input unit for the Inductive Resistance parameter of the Adjustable Phase 20, an input unit for the inductive resistance parameter for the Wing Phase 21, an input unit for the active resistance parameter for the regulated phase 22, a dividing unit 23, a comparison unit 24, a task unit 25 silytel 26, the motor movement 27. Electrode obazom apparatus operates as follows. The signal from the linear voltage sensor at the output terminals of the supply transformer 1 is fed to the input of multiplication unit 9, the second input of which receives a signal from the output of the unit to calculate sine 7. To the input of the sineating unit 7, a signal comes from the output of the unit for algebraic addition 15 The first input of the iKOTOporo, via the block for changing the sign 17, receives a signal from the sensor 4 of the phase angle between the linear voltage at the terminals of the supply transformer and the arc current of the adjustable phase. The second input of the algebraic addition unit 15 receives a signal from the c-sensor. The phase angle between the arc current of the lagging phase and the arc current of the controlled phase. The output from multiplier 9 is fed to the first input of the block for algebraically adding 16. The signal from sensor 5 of the phase angle between the outgoing phase arc current and the adjustable phase arc current is fed to the block input to calculate sine 6 and to the block input to calculate cosine 8. The signal from the output of the block for calculating sine 6 is fed to the input of multiplication unit 10, the second input of which receives the signal from the output of multiplying unit 13. The first input of multiplier 13 receives the signal from the current sensor of the adjustable phase 2 arc, and its second input d - signal from the input unit of the active resistance parameter of the adjustable phase 22. The signal from the output of multiplication unit 10 is fed to the unit to change sign 18 and then to the second input of the unit for algebraic addition 16. The signal from the output of the unit to calculate cosine 8 is fed to the input of multiplication unit 11, the second input of which is connected to the output of multiplier 12. At the first input of multiplication unit 12, a signal is received from an arc current sensor of an adjustable phase 2, and a signal from an input unit of an inductive impedance parameter iruemoy phase signal 20. The multiplying unit 11 with the output is supplied to the third input of the block for al1ebraicheskogo adder 16. Signal

The output of the lagging phase arc current sensor 3 is fed to the input of multiplication unit 14, the second input of which receives a signal from the input unit of the lagging phase inductive resistance parameter 21, the signal from the output of multiplying unit 14 is fed to the input of the unit to change the sign 1 and then to the fourth input block for algebraic addition 16. The signal from the output of the block for algebraic addition is fed to the first input of division unit 23, the second input of which receives a signal from the output of block 6, proportional to the sine of the phase angle between the arc current otstogoschay phase and arc current adjustable phase. A signal from the output of dividing unit 23, proportional to the voltage across the arc, is fed to the first input of the comparator unit 24. To the second input of the comparative unit 24, a signal is received from the sensor of the current of the arc of the adjustable phase. 2, At the output of the comparator unit 24. a signal Z aGd-bVj is formed, and the values of a and b come from the output of the task block 25. When the electric mode deviates from the preset, the signal goes to the amplifier 26 and then to the motor moving the electrode 27

Thus, the proposed device provides precise control of the arc power by its impedance. With this method of controlling the power of the arc, the disappearance of the supply voltage does not cause the electrode to move, since the signal at the junction output unit is zero.

The proposed device for regulating the electric mode of a ore-smelting furnace with a non-conductive hearth allows precise control of the furnace power,. eliminate the movement of the electrodes in case of disappearance of the supply voltage: and, thereby, increase the technical and economic performance of ore-smelting furnaces with non-conductive hearth. The economic effect from the introduction of the invention is 2.2 million rubles. in year.

Claims (2)

1. Sydorenko M.F. and others. Automation and mechanization of electric steel-smelting and ferroalloy production. M., Metallurgists, 1976, with. 30-44.,. 2. Rudnitsky VB Automation. ore electric smelting processes in non-ferrous metallurgy. M., Metallurgists, 1973, p. 121-125.