CN114754570A - Method and device for testing arc starting voltage parameters of direct current electric arc furnace - Google Patents
Method and device for testing arc starting voltage parameters of direct current electric arc furnace Download PDFInfo
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- CN114754570A CN114754570A CN202210291821.XA CN202210291821A CN114754570A CN 114754570 A CN114754570 A CN 114754570A CN 202210291821 A CN202210291821 A CN 202210291821A CN 114754570 A CN114754570 A CN 114754570A
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- 238000010891 electric arc Methods 0.000 title claims abstract description 53
- 238000000034 method Methods 0.000 title claims abstract description 53
- 238000012360 testing method Methods 0.000 title claims abstract description 48
- 238000001514 detection method Methods 0.000 claims abstract description 20
- 230000002159 abnormal effect Effects 0.000 claims description 12
- 238000005070 sampling Methods 0.000 claims description 8
- 238000004364 calculation method Methods 0.000 claims description 6
- 238000004590 computer program Methods 0.000 claims description 4
- 230000001174 ascending effect Effects 0.000 claims description 2
- 230000011664 signaling Effects 0.000 claims description 2
- 238000003723 Smelting Methods 0.000 abstract description 15
- 239000000463 material Substances 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000011217 control strategy Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B3/00—Hearth-type furnaces, e.g. of reverberatory type; Tank furnaces
- F27B3/10—Details, accessories, or equipment peculiar to hearth-type furnaces
- F27B3/28—Arrangement of controlling, monitoring, alarm or the like devices
Abstract
The invention relates to a method and a device for testing an arc starting voltage parameter of a direct current electric arc furnace, belonging to the technical field of industrial smelting. The method comprises the following steps: s1: controlling the power supply device of the DC arc furnace to output a voltage U with a preset amplitudesSimultaneously controlling the electrode to descend and collecting a loop current signal I and a pressure signal P; s2: in the descending process of the electrode, threshold judgment is carried out on the detection signal; s3: i is more than or equal to I in the descending process of the electrodestWhen the arc furnace power supply equipment outputs voltage, the electrode is controlled to keep the current position, and arc starting voltage parameter testing is carried out; s4: repeating the test for n times; s5: substituting the test data, and calculating for multiple times to obtain the load resistance R and the arcing voltage reference value Ust＝R*Ist. The invention can provide reliable arcing voltage parameters for the power supply device of the direct-current electric arc furnace, optimize the arcing process of the direct-current electric arc furnace, reduce the impact of arcing current and avoid the arcing failure phenomenon caused by the difference of the conductivity of furnace materials.
Description
Technical Field
The invention belongs to the technical field of industrial smelting, and relates to a method and a device for testing an arc starting voltage parameter of a direct current electric arc furnace.
Background
The DC arc furnace is developed based on the ultra-high power arc furnace, which is the combination of various related technologies of the ultra-high power arc furnace and the current generation of high-efficiency and high-power semiconductor current transformation technology. Compared with the traditional alternating current electric arc furnace, the direct current electric arc furnace has obvious advantages in the aspects of electric arc stability and heat transfer, meanwhile, the interference and impact on a power grid in the smelting process are small, and the power factor on the power grid side is high, so that the direct current electric arc furnace is an important development trend of industrial smelting.
However, the power supply equipment system of the direct current electric arc furnace is complex, an alternating current-direct current conversion module is added compared with the alternating current electric arc furnace system, the output voltage and current of the power supply equipment need to be controlled in real time in the whole smelting process, and the system control difficulty is high. During the process of arc striking in smelting, due to the fact that the contact area of the electrode on furnace charge changes or the conductivity of the furnace charge is different, the phenomenon of current impact or frequent arc breaking easily occurs by adopting the same arc striking voltage, the overall smelting stability is affected, and the smelting efficiency is reduced. Therefore, it is necessary to develop a method and a device for calculating the arc starting voltage parameters of the dc arc furnace suitable for various complicated working conditions.
Disclosure of Invention
In view of the above, the present invention provides a method and an apparatus for testing an arc starting voltage parameter of a dc arc furnace. The method is simple to implement, convenient and fast, can quickly detect the load characteristics, and provides proper arc starting voltage parameters for power supply equipment of the direct current arc furnace.
In order to achieve the purpose, the invention provides the following technical scheme:
a method for testing the arc starting voltage parameter of a direct current electric arc furnace comprises the following steps:
s1: controlling the power supply device of the DC arc furnace to output a voltage U with a preset amplitudesWhile controlling the electrode to descend and to adoptCollecting a loop current signal I and a pressure signal P;
s2: in the electrode descending process, the threshold value judgment is carried out on the detection signal, if the pressure P is high>PthWhen, I<Arcing Current IstIf the contact area of the electrode is abnormal or the conductivity of the furnace burden is abnormal, the electrode stops descending and abnormal alarm is given, and the furnace burden at the contact point is normal under other conditions;
s3: i is more than or equal to I in the descending process of the electrodestWhen the arc furnace power supply equipment outputs voltage, the electrode is controlled to keep the current position, and arc starting voltage parameter testing is carried out;
s4: controlling the power supply equipment of the arc furnace to output a preset amplitude voltage U1Recording loop detection peak current data I1Then adjusting the output voltage, and repeating the test for n times;
s5: substituting the test data into the loop formula U-R I + L-dI/dt, and calculating for multiple times to obtain the load resistance R and the arcing voltage reference value Ust＝R*Ist；
In the loop formula, I is a current peak moment and a current mean value of a last sampling moment, L is an inductance value and a loop stray inductance value of a loop filter, dI is a current difference value between the current peak moment and the last sampling moment during testing, and dt is a sampling time difference value.
Optionally, in S1, the voltage U is presetsThe amplitude is a percentage value of the rated voltage amplitude of the power supply device of the electric arc furnace.
Optionally, in S2, the pressure threshold PthThe percentage value of compressive strength of electrode used in electric arc furnace, arcing current value IstPercentage value of the rated current of the power supply for the arc furnace.
Optionally, in S4, the test is repeatedly performed by adjusting the voltage amplitude or adjusting the duration of the output voltage;
when the amplitude value of the variable voltage is repeatedly tested, the output voltage duration is fixed;
and when variable output voltage time duration is adopted, the amplitude of the output voltage is fixed.
The device for testing the arc starting voltage parameter of the direct current electric arc furnace based on the testing method comprises the following steps:
the first detection module: the pressure intensity data is used for detecting the pressure intensity data of the electrode of the electric arc furnace in the test process;
a first control module: the device is used for controlling the movement of the electrode of the electric arc furnace in the test process, including the ascending, descending and stopping of the electrode;
a second detection module: the device is used for detecting the output current data of the power supply device of the electric arc furnace in the test process;
a second control module: the device is used for controlling the output voltage of the electric arc furnace power supply device in the test process, and comprises a voltage amplitude and a time length;
a first calculation module: the method is used for calculating the load resistance value and the arcing voltage parameter of the direct current electric arc furnace.
Optionally, the pressure P applied to the detection electrode by the first detection module>PthAnd outputting a furnace charge conductivity abnormal signal, and controlling the electrode to ascend to the initial position by the first control module.
Optionally, the second detection module outputs an overcurrent fault signal when the detected current is greater than the maximum current allowed by the electric arc furnace power supply device, and the second control module controls the electric arc furnace power supply device to stop outputting the voltage.
Optionally, the first computing module is a computer device, and includes a processor, a readable and writable memory, and a stored computer program.
A computing module, the first computing module implementing the computing method of claims 1-6 by a processor executing a computer program in a memory.
The invention has the beneficial effects that:
(1) the method does not need to add extra hardware facilities to the original system, the mentioned software and hardware modules can be reused for the internal modules of the original direct current electric arc furnace system, and the method is only added to the original control strategy. The method has the advantages of short calculation time and good effect, can dynamically adjust the arcing voltage according to different loads, can be adopted in any period of smelting, effectively shortens the arcing time of the direct current electric arc furnace, reduces current impact in the arcing process, optimizes the arcing process and improves the industrial smelting efficiency.
(2) The method of the invention tests by controlling the output pulse voltage of the power supply device of the direct current electric arc furnace, has simple operation, easy realization, no influence on the original smelting process, and less energy loss generated in the whole process, and can be widely applied to various direct current electric arc furnace smelting occasions.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the means of the instrumentalities and combinations particularly pointed out hereinafter.
Drawings
For the purposes of promoting a better understanding of the objects, aspects and advantages of the invention, reference will now be made to the following detailed description taken in conjunction with the accompanying drawings in which:
FIG. 1 is a flow chart of a method for calculating arc starting voltage parameters of a DC arc furnace according to the present invention;
FIG. 2 is a topological block diagram of an arc starting voltage parameter testing device of the DC arc furnace according to the present invention;
FIG. 3 is a topological diagram of a power supply device of the DC arc furnace in the embodiment;
fig. 4 is a current waveform diagram obtained by testing the method based on the embodiment of the invention.
Detailed Description
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present invention in a schematic way, and the features in the following embodiments and examples may be combined with each other without conflict.
Wherein the showings are for the purpose of illustrating the invention only and not for the purpose of limiting the same, and in which there is shown by way of illustration only and not in the drawings in which there is no intention to limit the invention thereto; to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.
The same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar components; in the description of the present invention, it should be understood that if there is an orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "rear", etc., based on the orientation or positional relationship shown in the drawings, it is only for convenience of description and simplification of description, but it is not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore the terms describing the positional relationship in the drawings are only used for illustrative purposes and are not to be construed as limiting the present invention, and the specific meaning of the terms described above will be understood by those skilled in the art according to the specific circumstances.
In this embodiment, the device for testing the arc starting voltage parameter of the dc arc furnace is shown in fig. 2, wherein the topological schematic diagram of the power supply device of the dc arc furnace is shown in fig. 3, and an uncontrollable rectification and dc chopping structure is adopted. The basic parameters of the whole system of the direct current electric arc furnace are as follows: the rated capacity is 4MVA, the rated voltage is 500V, the rated current is 8kA, the inductance value of the direct current filter at the output side is 1.2mH, the compressive strength of the graphite electrode is 21MPa, the interrupt period of system software is 250us, and the corresponding minimum sampling period is 250 us. Setting a preset amplitude voltage U by combining data such as field furnace material, graphite electrode performance and the likes80V, electrode pressure threshold Pth5MPa, arcing current Ist300A, the specific implementation steps are as shown in fig. 1, and include the following five steps:
s1: the second control module controls the power supply device of the direct current electric arc furnace to output a preset amplitude voltage of 80V, the first control module controls the electrode to descend, and the first detection module and the second detection module collect a loop current signal I and a pressure signal P;
s2: in the descending process of the electrode, the first detection module and the second detection module carry out threshold judgment on the detection signals, when the pressure P is greater than 5MPa, the sampling current I is still smaller than the arcing current 300A, the contact area of the electrode is considered to be abnormal or the conductivity of furnace burden is considered to be abnormal, meanwhile, an abnormal alarm is output, and the other conditions are considered that the furnace burden at the contact point is normal. When the system outputs an abnormal alarm, the first control module controls the electrode to stop descending.
S3: when the detection current I is larger than the arcing current 300A in the electrode descending process, the second control module controls the power supply equipment of the electric arc furnace to stop outputting voltage, and the first control module controls the electrode to keep the current position to carry out arcing voltage parameter test;
s4: because the power supply device of the direct current electric arc furnace adopts an uncontrollable rectification and direct current chopping structure, and the direct current voltage at the front end of the chopping module is uncontrollable, the direct current electric arc furnace is tested by fixing the amplitude of the output voltage and adjusting the time length of the output voltage. The output voltage of the power supply equipment of the direct current electric arc furnace is the direct current bus voltage at the front end of the chopping module, and the time lengths of the output voltage are adjusted to be 0.5ms, 1ms, 1.5ms and 2ms respectively for repeated testing;
FIG. 2 is a topological block diagram of an arc starting voltage parameter testing device of the DC arc furnace according to the present invention;
FIG. 3 is a topological diagram of a power supply device of the DC electric arc furnace in the embodiment;
s5: according to the loop formula U-R I + L dI/dt, the waveform of the output voltage amplitude 750V and the output voltage duration 1ms is taken as an example, and the waveform is shown in fig. 4. In the loop formula, U is 750V, and I is 0.5 (I)1+I2)＝486.5A，L＝1.2mH，dI＝(I2-I1) 115A; dt-250 us, load R-0.407 Ω can be calculated. After multiple tests and calculations, the mean value of the load resistance R is 0.381 omega, and the arc starting voltage parameter U is calculatedst＝114V。
In conclusion, after the method for calculating the arcing voltage parameters and the testing device are provided by the method, the direct-current electric arc furnace system can effectively identify the conducting working condition of furnace burden, and calculate the proper arcing voltage through testing, so that the current impact of the system is reduced in the smelting process, and the frequent arc breaking phenomenon during arcing is avoided, thereby improving the industrial smelting efficiency and optimizing the smelting process.
Finally, the above embodiments are only intended to illustrate the technical solutions of the present invention and not to limit the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all of them should be covered by the claims of the present invention.
Claims (9)
1. A method for testing the arc starting voltage parameter of a direct current electric arc furnace is characterized by comprising the following steps: the method comprises the following steps:
s1: controlling the power supply device of the DC arc furnace to output a voltage U with a preset amplitudesSimultaneously controlling the electrode to descend and collecting a loop current signal I and a pressure signal P;
s2: in the descending process of the electrode, the threshold value judgment is carried out on the detection signal, and if the pressure P is higher than the threshold value>PthWhen, I<Arcing current IstIf the contact area of the electrode is abnormal or the conductivity of the furnace burden is abnormal, the electrode stops descending and abnormal alarm is given, and if the other conditions are met, the furnace burden at the contact point is normal;
s3: i is more than or equal to I in the descending process of the electrodestWhen the arc furnace power supply equipment outputs voltage, the electrode is controlled to keep the current position, and arc starting voltage parameter testing is carried out;
s4: controlling the power supply equipment of the arc furnace to output a preset amplitude voltage U1Recording loop detection peak current data I1Then adjusting the output voltage, and repeating the test for n times;
s5: substituting the test data into the loop formula U-R I + L-dI/dt, and calculating for multiple times to obtain the load resistance R and the arcing voltage reference value Ust＝R*Ist；
In the loop formula, I is a current peak moment and a current mean value of a last sampling moment, L is an inductance value and a loop stray inductance value of a loop filter, dI is a current difference value between the current peak moment and the last sampling moment during testing, and dt is a sampling time difference value.
2. The method for testing the arc starting voltage parameters of the direct current electric arc furnace according to claim 1, wherein the method comprises the following steps: in the step S1, a preset voltage UsThe amplitude is a percentage value of the rated voltage amplitude of the power supply device of the electric arc furnace.
3. The method for testing the arc starting voltage parameters of the direct current electric arc furnace according to claim 1, wherein the method comprises the following steps: in said S2, pressure threshold PthThe percentage value of compressive strength of electrode used in electric arc furnace, arcing current value IstPercentage value of the rated current of the power supply for the electric arc furnace.
4. The method for testing the arc starting voltage parameters of the direct current electric arc furnace according to claim 1, wherein the method comprises the following steps: in the step S4, the test is repeatedly performed by adjusting the voltage amplitude or adjusting the output voltage duration;
when the amplitude value of the variable voltage is repeatedly tested, the output voltage duration is fixed;
and when variable output voltage time duration is adopted, the amplitude of the output voltage is fixed.
5. The device for testing the arc starting voltage parameter of the direct current electric arc furnace based on the testing method of any one of claims 1 to 4 is characterized in that: the device includes:
the first detection module: the pressure intensity data is used for detecting the pressure intensity data of the electrode of the electric arc furnace in the test process;
a first control module: the device is used for controlling the movement of the electrode of the electric arc furnace in the test process, including the ascending, descending and stopping of the electrode;
a second detection module: the device is used for detecting the output current data of the electric arc furnace power supply device in the test process;
a second control module: the device is used for controlling the output voltage of the electric arc furnace power supply device in the test process, and comprises a voltage amplitude and a time length;
a first calculation module: the method is used for calculating the load resistance value and the arcing voltage parameter of the direct current electric arc furnace.
6. According to claim5 the arc starting voltage parameter testing device of the direct current electric arc furnace is characterized in that: the first detection module detects the pressure P applied to the electrode>PthAnd outputting a furnace charge conductivity abnormal signal, and controlling the electrode to ascend to the initial position by the first control module.
7. The arc starting voltage parameter testing device of the direct current electric arc furnace as claimed in claim 6, wherein: and the second detection module outputs an overcurrent fault signal when the detected current is greater than the maximum current allowed by the electric arc furnace power supply device, and the second control module controls the electric arc furnace power supply device to stop outputting the voltage.
8. The arc starting voltage parameter testing device of the direct current electric arc furnace according to claim 5, characterized in that: the first computing module is a computer device comprising a processor, a readable and writable memory and a stored computer program.
9. A computing module, characterized by: the first computing module implements the computing method of claims 1-6 by a processor executing a computer program in a memory.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115255566A (en) * | 2022-09-26 | 2022-11-01 | 苏芯物联技术(南京)有限公司 | Welding deviation real-time intelligent detection method based on high-quality time domain characteristics |
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| CN111363886A (en) * | 2020-04-17 | 2020-07-03 | 中冶京诚工程技术有限公司 | Method and device for controlling operation of electric arc furnace |
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Patent Citations (7)
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| JP2007026799A (en) * | 2005-07-14 | 2007-02-01 | Toshiba Mitsubishi-Electric Industrial System Corp | Electrode elevation controller for arc furnace |
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