SU762215A1 - Three-phase arc furnace short circuit - Google Patents

Description

The invention relates to electrothermal and can be used on electric arc furnaces used for melting metals in the engineering and metallurgical industries.

There is a short network, made according to the “asymmetric triangle on the electrodes” scheme, (1], in which the current leads of all three phases in the whole section from the busbars from the transformer room to the electrodes are located on the same level.

The disadvantage of this short network is high inductive and active resistance, high uneven distribution of power and the impossibility of supplying increased power without significant losses.

The closest in technical essence is a short network of a three-phase arc furnace, containing transformer bus leads, flexible cables connected through shoes to pipes, and the pipelines of the outer phases are located in one plane, and the pipelines of the middle phase in a section of 0.4–0.6 throughout the lengths of the pipe-pipes are equidistant from the pipe-pipes of the extreme phases for a distance, equal to 2

distance between the extreme phases [2].

The disadvantage of this short network is that if the electrode holders are not arranged correctly, which often happens in real conditions of operation of arc steel-smelting furnaces (bypassing electrodes for unequal length, different levels of charge under the electrodes of all three phases, different density of charge under the electrodes, etc. ) the parameters of this short network deteriorate sharply.

To increase the stability of the electrical parameters in the short network, the middle phase pipelines on the remaining length are located in the same plane as the extreme phase pipes.

The drawing shows a diagram of a short network.

The busbar 1 is connected to the secondary winding of the transformer. Flexible cables 2 connect the busbar terminals 1 to contact shoes 3 fixed on the brackets 4 of the electrode holders 5. The electrical connection of the contact shoes 3 to the heads 6 carrying the electrodes 7 is carried out with the help of pipe joints. Tube 8 extreme phases are located on the same level throughout the length of the electrode holder. Truboshy 9 average f3

762215

Zy by 0.4–0.6 lengths of the electrode holder are raised in such a way that in the cross section of the pipe of all phases are located along the vertices of an equilateral triangle. Moreover, the vertex of the triangle can be turned up (as shown in the figure) or down. On the remaining length of the electrode holder, the tubes of all three phases are located on the same level.

Tests of the proposed short circuit on a DSP — 80A electric furnace at Chelyabmetzavod showed that this design reduces the electrodynamic interaction of the current leads of different phases, reduces vibration and rocking of the electrode holders and increases the stability of the furnace. Measurements of electrical characteristics carried out on this furnace by Centrenergochermet showed that the parameters of the new short network are more stable with fluctuations of the current value, which creates better conditions for regulating the electric mode and allows more power to be brought to the bath.

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Claims (1)

Claim A short network of three-phase electric arc furnace containing transformer bus terminals 5, flexible cables connected via shoes to pipes, the pipelines of the outer phases are located in the same plane, and the pipelines of the middle phase in the section of 0.4-0.6 in length of the entire pipe-length extreme phases by a distance equal to the distance between the extreme phases, characterized in that, in order to increase the stability of the electrical parameters, the middle phase pipes on the remaining length are located in one plane with pipelines of extreme phases.