ARC-FURNACE MODEL FOR THE STUDY OF FLICKER COMPENSATION IN ELECTRICAL NETWORKS

This paper presents an arc-furnace model consisting of non-linear, time varying resistance where two different time-variation laws of arc length are considered. One consists of a periodic, sinusoidal law, the other of a band-limited white-noise law. The arc-furnace model is implemented by EMTP, referring to actual electric-plant configurations. Simulations are reported where the values of flicker sensation and short-term flicker severity, P(ST), are determined according to UIE specifications. It results that the model based on sinusoidal time-variation law can be useful for worst-case approximations, while the model using white-noise law is able to fit flicker measurements made in electric plants supplying arc furnaces. The models are used to investigate the effect on flicker compensation of the insertion of series inductors at the supply side of the furnace transformer. It is shown that considerable reduction of P(ST) is obtained at the point of common coupling by series inductor installation at constant furnace active power.