Mutual Influence of the Melting Stage and Electric Arc Current Harmonic Composition in Different Types of Electric Arc Furnaces

Abstract

The authors of the article carried out experimental studies of the harmonic current composition of arc steel-melting furnaces of various capacities and classes operating at various metallurgical enterprises in Russia. This made it possible to carry out a comprehensive analysis of the changes in the higher current harmonics of the electric steel-making units, to identify patterns of changes in individual harmonic components, as well as to determine the average and maximum harmonic levels for arc furnaces of each type. Also, a comparative analysis was made of the change rate of the total effective values of even and odd harmonic components, which showed an important pattern in exceeding the rate of attenuation of even harmonics of an arc furnace over odd ones several times. On the basis of this, it was shown the expediency of using the rms current of even harmonics for the purpose of diagnosing the melting stages in an electric arc furnace with the classical technological process. This principle formed the basis for the structure of the new control system for the electric mode of the furnace, which implements the diagnostic technique for the melting stage according to the harmonic composition of the electric arc current signal