Piotr Drozdowski

This article presents the results of the analysis of a six-electrode pulse current electric arc furnace (EAF). The characteristics of a power supply system for an EAF are presented for symmetrical states and the most probable asymmetrical states.

In this paper the computer model of the cage induction machine taking into account magnetic non-linearity is presented. The model contains the mathematical model of the induction machine recorded as an S-function and the connecting blocs attaching the model from one side to the three-phase terminals of the supply system model and from the other to the system of mechanical model. Hence, Sim-Power-Systems and Sim-Mechanics libraries can be used. Such a methodology allows for various drives modelling where the induction machine operates as a motor or a generator and cooperates with power electronics system. Using wide range of SIMULINK possibilities the various control techniques can be applied. Using this methodology the own mathematical models of other electrical machines together with the SIMULINK library models can be used.

Electrical machines, such as welding arc devices, negatively affect the quality of electric power in a supply network, which in turn affects the operation of loads connected in parallel. The aim of this paper is to present the results of research confirming the positive effect of a passive L-C filter dedicated for welding devices. The paper demonstrates the effectiveness of the filter, which not only helps to reduce the total voltage distortion, but the reactive power compensation as well. The results confirm that installing a passive controlled L-C filter significantly reduces power losses in elements of the power supply network. The conducted research leads the authors to recommend using such filters in electrical arc devices.

In the article based on the fundamental laws of physics and mathematics has been formulated mathematical model to analyze the electromagnetic waveforms in electrical power systems with non-linear loads, such as arc furnaces.