Short-Term Hydrothermal Scheduling Based on Lagrange Function and Determining Initial Hydrothermal Generations

Abstract

The paper presents an effective method based on the Lagrange multiplier theory to solve optimal scheduling of hydrothermal power system. Optimal scheduling of hydrothermal power systems is a great important problem to electric utility systems, the main objective of the problem is to determine the generation for each plant during scheduling period of time such that the total system generation cost is minimum while satisfying the system constrains of the generating limits and available water. The problem of optimal economic operation of hydrothermal power systems with fixed head hydro plants is considered and has had many researches about this. Determining of water discharge at the first interval is performed in this paper and lead to a low number of iteration and short computation time for convergence. The proposed method is tested on one system consisting of one hydro and one thermal plant through two examples.

Conventional and Metaheuristic Optimization Algorithms for Solving Short Term Hydrothermal Scheduling Problem: A Review

“…Reference [27] implemented a simplified Lagrangian multiplier-based algorithm to solve both NCSTHTS and CSTHTS problem in which water discharge rate was modelled as a quadratic function of hydro-power generation and fuel cost was modelled as a quadratic function of thermal power generation. The NC-STHTS problem was solved in reference [28] using Lagrange function for a fixed head problem. Figure 1 gives the year wise distribution of the number of articles published on STHTS using variants of Lagrangian relaxation and Benders decomposition.…”

“…Canonical version with relaxation coefficient [4], [5], [13]- [15], [27], [28] Robust solutions achieved though the later metaheuristic implementations helped achieving good approximates to global optimum solution . Premature convergences to local optima were also observed while implementing these algorithms.…”