Daily integrated generation scheduling for thermal, pumped‐storage, and cascaded hydro units and purchasing power considering network constraints

Abstract

SUMMARYWe have developed an innovative power generation scheduling method using quadratic programming (QP). The advantage of using our method is that it simultaneously solves unit commitment and economic load dispatch. We relax the binary variables of the unit state into continuous variables to apply QP to this problem. We also add a penalty term to converge the value of those variables to 0 or 1 to the objective function: the sum of the fuel costs and the start-up costs. This penalty term depends on the per-unit fuel cost. The possibility of its variable converging to zero increases as the cost increases. This method was applied to a test system of daily generation scheduling that consisted of 29 thermal units, two pumped-storage units, four cascaded hydro units, and one transmission. The schedule satisfied all constraints, that is, load-power balance, operation reserve, power flow, minimum up/down-times, and fuel consumption. This result shows that the proposed method is effective.

Optimal Scheduling of Hydro–Thermal–Wind–Photovoltaic Generation Using Lightning Attachment Procedure Optimizer

“…These constraints with the valve-point loading impact make this problem a non-linear and complicated optimization problem. Several analytical optimization methods have been employed such as dynamic programming (DP) [1], mixed-integer linear programming [2], nonlinear programming (NLP) [3], and Lagrange relaxation (LR) [4]. It should be highlighted here that these methods suffer from stagnation, and they are not able to provide the optimal solution due to the nonlinearity and composite constraints of the STHS problem.…”