Direct-current control method and device for three-phase alternating-current electric arc furnace

Abstract

The invention discloses a direct-current control method and device for a three-phase alternating-current electric arc furnace. The method comprises the steps of selecting a first electrode serving asa negative electrode and second and third electrodes serving as positive electrodes from three electrodes of the three-phase alternating-current electric arc furnace; controlling a flexible power supply device to output a first direct-current power supply voltage between the second electrode and the first electrode and output a second direct-current power supply voltage between the third electrodeand the first electrode; and controlling the three electrodes of the three-phase alternating-current electric arc furnace to execute the descending action till the three electrodes of the three-phasealternating-current electric arc furnace make contact with a smelted object in the furnace, so that a first direct-current electric arc current is generated between the second electrode and the firstelectrode, and a second direct-current electric arc current is generated between the third electrode and the first electrode. The problems that the electric energy transmission efficiency is low andarc breakage is likely to occur due to the fact that the alternating current zero-crossing times are too frequent can be solved, and the smelting efficiency of the alternating-current electric arc furnace is improved.

Description

technical field [0001] The invention relates to the field of industrial smelting, in particular to a DC control method and device for a three-phase AC electric arc furnace. Background technique [0002] This section is intended to provide a background or context to embodiments of the invention that are recited in the claims. The descriptions herein are not admitted to be prior art by inclusion in this section. [0003] As we all know, electric arc furnaces can be used to smelt metals such as scrap steel. As the name implies, an AC electric arc furnace refers to an electric arc furnace that is directly connected to the AC grid and powered by the AC grid. After the AC electric arc furnace takes power from the public grid 1, it can convert the high voltage of the public grid into the low voltage required for smelting (for example, 35KV / 1.5KV) through the high-impedance reactor in series, and the electric energy passes through the short network (water-cooled cable And its acc...

AI Technical Summary

Problems solved by technology

[0007] The embodiment of the present invention provides a DC control method for a three-phase AC electric arc furnace, which is used to solve the problem that the existing three-phase AC electric arc furnace is powered by three-phase AC voltage, and the frequency of zero-crossing of the AC current is too frequent, resulting in the power transmission efficiency of the electric arc furnace The method includes: selecting the first electrode as the negative electrode, the second electrode and the third electrode as the positive electrode from the three electrodes of the three-phase AC electric arc furnace; controlling the flexible power supply device to the third electrode Output the first DC power supply voltage between the second electrode and the first electrode, and output the second DC power supply voltage between the third electrode and the first electrode; control the three electrodes of the three-phase AC electric arc furnace to perform a descending action until the three-phase AC The three electrodes of the electric arc furnace are in contact with the smelt in the furnace, so that the first DC arc current is generated between the second electrode and the first electrode, and the second DC arc current is generated between the third electrode and the first electrode

[0008] The embodiment of the present invention also provides a DC control device for a three-phase AC electric arc furnace, which is used to solve the problem that the existing three-phase AC electric arc furnace is powered by three-phase AC voltage, and the frequency of zero-crossing of the AC current is too frequent, resulting in the power transmission of the electric arc furnace. The technical problem of low efficiency and prone to arc interruption, the device includes: an electrode configuration module, which is used to select the first electrode as the negative electrode, the second electrode and the third electrode as the positive electrode from the three electrodes of the three-phase AC electric arc furnace The power supply control module is used to control the flexible power supply device to output the first DC power supply voltage between the second electrode and the first electrode, and output the second DC power supply voltage between the third electrode and the first electrode; the electrode control module, The three electrodes used to control the three-phase AC electric arc furnace perform a downward movement until the three electrodes of the three-phase AC electric arc furnace touch the smelt in the furnace, so that the first DC arc current is generated between the second electrode and the first electrode, and the third A second DC arc current is generated between the electrode and the first electrode

[0009] The embodiment of the present invention also provides a computer device to solve the problem that the existing three-phase AC electric arc furnace is powered by three-phase AC voltage, and the frequency of zero-crossing of the AC current is too frequent, resulting in low power transmission efficiency of the electric arc furnace and prone to arc breaks The computer equipment includes a memory, a processor, and a computer program stored on the memory and operable on the processor. When the processor executes the computer program, the above-mentioned DC control method for the three-phase AC electric arc furnace is realized.

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