SU1356270A2 - Power regulator of multiphase electric arc furnace - Google Patents

Abstract

The invention relates to electrical engineering. The aim of the invention is to increase the productivity of the furnace by improving the quality of regulation. An n-1 phase comparison error signal and a n-1 key are added to the power-on sequence block. The controller provides the ability to move the electrode of one phase up simultaneously with the movement of the electrode of the other phase down. This leads to stabilization of the regulation process. 1 il. OO SD JV to | OK)

Description

This invention relates to electro-metallurgy, in particular, to power regulators of electric arc furnaces.

The purpose of the invention is to increase the productivity of the furnace by improving the quality of regulation.

The drawing shows the Fschktsional scheme for a particular case with n 3 (a, b, c),

The current values of a b, from the controlled parameters of the furnace 1 are fixed by measuring devices 2A, 2B, 2C and are algebraically summed with the given values of these parameters a, b, c. The resulting phase mismatch signals hell, bd, cd are fed to the input of the block, the sequence of switching on and then to the inputs of the 4AB, 4AC elements of the comparison of the signals hell, and b, and Cd by the sign and to the inputs of the selection elements modules. The output of the selection element of the module of its phase 5A is connected directly to the input of the element of comparison 6A, and the outputs of the selection elements of the modules of the compared de-matching signals are connected via analog switches 7B and 7C, which are controlled by elements 4AB and 4AC. Comparison element 6A, whose output serves as the output of the turn-on-order block, is connected to the logic input of the drive system 8A,

The regulator works as follows.

The practice of moving the electrode of phase A is prohibited only if

if a is smaller in magnitude than the error signal, having the same sign with it. With different signs of mismatch signals, i.e. If it is necessary to move the electrodes in different directions, the testing of the movement is placed in these phases simultaneously and independently of the level of mismatch.

Consider the principle of operation of the device on a specific example. For simplicity, let us take control over the currents in the phases of the furnace. Let I, Igj, I (- be the predetermined values of the phase currents in relative units, (I ---, where I is the nominal current IH

Shl.

-AZ - - VZ - S -

1д, 1ц, (- - the current value of the current of the corresponding phase in relative units. DT, ь, ul - the difference between the set and the current value of the current of the corresponding phase is proportional to the error signal received at the input of the regulator.

Set

IA

 1.2 d, - 1 - 1, 2 -0,2 0,2 t., 2 0,8

 1,0 ulc

ABOUT.

5 5 o

0 5

0

five

(Mb) (d1d) (Ale).

Since the mismatch signals in phases A and B have different signs, the corresponding comparison element on the 4AB sign acts on the additional key 7B, closing it. The signal (Vd) at the input of the modulo element does not pass and the phase A electrode is allowed to move upwards simultaneously with the movement of the phase B electrode downwards. The restoration of the specified currents in these phases occurs simultaneously. The possibility of moving two electrodes in different directions leads to the stabilization of the control process, since it retains the total load resistance between the phases of these electrodes, thereby stabilizing the linear current of these phases (in the considered example it is the current) „

Claims (1)

The use of the proposed controller allows to improve the quality of regulation and thereby increase the productivity of the equipment and the amount of metal produced. Formula and gain Power regulator of arc MANY phase electric furnace St. No. 639160, characterized in that, in order to improve the electric furnace performance by improving the quality of regulation, the power-on unit for each of the n phases is additionally equipped with p-1 elements for comparing the phase error signals by the sign and 11-1 keys connected between the outputs of the module allocation elements Signals n-1 of other phases and inputs of a unit of comparison modulo, the control inputs of the keys are connected to the outputs of the elements of the phasing of the phase error signals by the sign, the first input of each of the 313562704 They are connected to the input of the output element — to the input of the selection element of the error signal module of the error signal of one of this phase, and the second input of each of the other phases. Compiled by E. Kosarev Editor S. Lisin Tehred L. Serdyukova Proofreader S. Cherni 5815/57 Circulation 799 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk iab., d. 4/5 Production and printing company, Uzhgorod, st. Project, 4