Harmonics and Flicker in an Iron and Steel Industry with AC arc furnaces

Abstract

An AC arc furnace is an unbalanced, non-linear and time-varying load, which can cause many power quality problems to the electric network inside the plant and in its electrical vicinity. Although different studies addressing harmonics and flicker analyses on arc furnaces can be found in the bibliography, it is very difficult obtain an exact model that considers all the parameters that influence the process, and therefore it is necessary to obtain actual measurements under different conditions. This paper presents measurement results for harmonic distortion, flicker and unbalance obtained over three different measurement campaigns on an iron and steel industry (SNL), as well as the pertinent conclusions. Measurement campaigns were performed on an AC arc furnace of 83 MW (170 TM) with a 120 MVA transformer connected by a ‘dirty’ 220 kV line (55 km) to the Substation of Carregado, where other feeders supply industrial and domestic consumers. Finally, the dynamic behaviour of an SVC will be analysed and compared to that of a STATCOM by means of simulation studies.