Real-Time Measurement of Electric Arc-Furnace Disturbances and Parameter Variations

The general nature of electrical-supply network disturbances caused by arc-furnace operation is reviewed, including the guidelines adopted in several countries concerning disturbance-level estimation for single-and multifurnace installations. The meters available for the measurement of voltage flicker, including the international standard meter proposed by the International Union of Electroheat (UIE) are briefly described. The basic statistical properties of arc-furnace disturbances and parameter variations, treated as random variables, are discussed. Measured data are used to examine the probability distributions for variations in furnace voltage and current. Particular attention is given to methods of reliably measuring the disturbance and parameter-variation levels in real time on-line. Strategies are developed, and a microprocessor-based data-acquisition system, developed for this purpose, is described.