A novel method of electrical arc furnace modelling for flicker study

Abstract

Abstract:Voltage flicker and harmonics are the power quality problems which are introduced to the power system as a result of nonlinear and stochastic behavior of the arc furnace operation. To analyze harmonic and flicker generated by an arc furnace, accurate arc furnace models are needed. In this paper, different arc furnace models with different level of complexity are reviewed.In the first part of this paper a new developed time domain static model based on a piece-wise linear approximation of the V-I characteristics of the arc furnace is presented. While static arc models are useful for harmonic studies, dynamic models are useful for power quality studies specially the study of voltage flicker.In the second part of the paper, dynamic model for an arc furnace using MATLAB (Simulink) is presented. In addition to this, the novelty of this simulation technique lies in the fact that the variation of power transmitted to the load by the arc furnace during the cycle of operation is considered, thus making the proposed model more accurate and dependent on the operating conditions of the load.Finally recommendations are made for the application of some of these models and the accuracy of the presented model to other models from the practical point of view by using MATLAB is shown.

Modeling of the Electric Arc Behavior of the Electric Arc Furnace

“…The improved models introduced by this paper help to obtain the dynamic or static voltage-current characteristics of the electric arc. It can be noticed that these characteristics obtained with the proposed models represent more accurately the real characteristic of the electric arc, as compared to the model presented in [5], because in reality, when the voltage of the arc reaches the extinction voltage value, u ex , the arc voltage continues its variation for a moment of time, and will not change it immediately.…”

“…As compared to the model presented in [5] the following differences arise: • A different electric arc functioning zone is defined; • In the case the value of the current is below -i 2 or above than i 2, one can notice that the voltage variation is constant, maintained at the extinction voltage value of the electric arc; • The range within which the dynamic voltage-current characteristic can vary is larger than the one illustrated by the model presented in [5]. …”

“…The model under analysis is described in [5] and [11] is based on the linear approximation of the typical voltage-current characteristic of the electric arc. This model is given in relation (1).…”

“…In order to implement the mathematical models of the electric arc the power supply diagram of the electric arc furnace for a single phase [5] was used because its behavior is almost the same for the other two phases. This diagram can be observed in figure 4, this including the electric arc circuit supplied by alternative voltage from figure 1.…”

A New Method for Fundamental Signal Extraction Based on Wavelet Transform

“…Nowadays, with increasing the use of power electronic devices, EAFs (AC and DC), and induction furnaces, voltage and current harmonics are injected into the power systems [1][2][3][4]. These harmonics cause some problems such as decreasing capacity of transmission lines and increasing losses in power systems [5,6].…”