Production Scheduling with Power Price Coordination in Steel Industry

This paper addresses the problem of scheduling n jobs with power price consideration at the production stage of steelmaking. The total cost of power consumption whose price is a linear function of the load. The constraints of power supply capacity are considered besides the regular constraints of steel production constraints. A subgradient method-based Lagrangian relaxation algorithm is developed. After the machine capacity and the power supply limitation constraints are relaxed, the original problem is decomposed into easier time period-level subproblems, which can be solved to optimality by a polynomial algorithm. Testing results show that the proposed methods can generate near-optimal schedules with average duality gaps less than 7%.