Electronic based equipment for flicker mitigation

In this paper, two new approaches for arc furnace flicker mitigation are presented: the unified power flow controller (UPFC) and the series superconducting magnetic energy storage (SMES). These power electronic devices are more expensive than passive or classical equipment of the same rating, but present a better rating versus efficiency. An arc furnace induces different kinds of disturbances during the melting of scraps. Reactive compensation is needed to improve the efficiency of process and to mitigate the disturbances caused to the network. This paper presents different kinds of compensation: active and reactive by shunt and series compensation. It shows how the UPFC or the series SMES can be optimized to take care of all disturbances. The compensation of an AC furnace by these electronics equipment based on an EMTP model are investigated. Finally the paper presents the basic design and control of the series SMES and the UPFC and the comparison between these two structures in terms of rating and flicker mitigation for a real 100 MVA arc furnace.