Plantwide control for the electricity power demand control system

Abstract

Plantwide control design for the economically optimum operation of the power demand control system and applied to an iron and steel plant, which is consisted of a supervisory control layer on top for ensuring feasibility and economically optimal operation and several regulatory control units that ensure safe and stable operation. The supervisory layer has two main tasks. First, there is a supervisory part that adopts time series forecasting method to predict future total electric power load of the plant, and ensure that load trend is not exceeded the maximum. Second, it switches the controlled variables according to changes in active constraints at the economic optimum. In the regulatory control layer, the controlled objects are the EAF (electric arc furnace) that receives the supervisory layer's set-point and controls the electrode lifting to change the electric power based on model predictive control. A strategy of coordinating the regulatory control units is used to just key unconstrained set points for optimizing an economic criterion such as operation profit or energy consumption or production rate. The plantwide control system is a good solution to optimize the relationship between the supervisory and regulatory control layers, and controls the iron and steel plant's power demand in the reasonable range, and reduces the electricity costs.