Load Scheduling Strategy to Improve Power Quality in Electric-Boosted Glass Furnaces

In glass furnace boosting, particularly in the tin bath and annealing lehr heating systems, an ac-ac power converter is normally employed by the industry. This Triac-based converter driven by integral cycle control (ICC) is employed to provide highly accurate power to the resistive heating elements distributed into the furnace. The advantages of ICC include low inrush current and increased reliability; although its impact on power quality (PQ), due to the subharmonic distortion produced, is significant. While different strategies for energy demand management have been implemented to date, they have not adequately addressed this PQ issue. Thus, the goal of this research is to establish an optimal electrical load scheduling strategy considering criteria about PQ and thermal behavior through a mixed-binary quadratic programming problem which exploits the ICC advantages avoiding PQ degradation.