Analysis of the propagation of voltage fluctuations created by electric arc furnaces.

摘要

Electric utility companies often serve loads that create fluctuations in the supply voltage. Among the most significant of these loads is the ac electric arc furnace (EAF). When an electric lamp, e.g. an incandescent light bulb, is exposed to a fluctuating source voltage, fluctuations in light output or lamp flicker will occur. If the resulting lamp flicker is severe enough, customers will complain. Because EAFs are often the largest revenue producing loads connected to the system, it is advantageous for utility companies to serve these loads. Having an accurate knowledge of how the voltage fluctuations created by an EAF propagate throughout the system, and potentially affect customers, is paramount for an electric utility company. Flicker transfer coefficients are often employed to estimate the manner in which EAF created voltage fluctuations propagate throughout the system. However, existing theoretical models are not as accurate as they should be, and as a result, rules of thumb, which may or may not be accurate, are often employed. The main objective of this research is to analyze the propagation of voltage fluctuations created by EAFs, and develop accurate theoretical models and methods that can be used to determine flicker transfer coefficients for use in allocating customer flicker emission limits, as well as determine what impact the resulting flicker will have on a residential customer's power quality. The subject research focuses on the flicker produced by EAFs since these loads create the most difficulty for utilities; however, many of the results will be directly applicable to other types of disturbing loads such as arc welders, pellet mills, etc.