Short-term environmental/economic hydrothermal scheduling

Abstract

This paper proposes a new technique based on lexicographic optimization and ɛ-constraint method to solve the combined economic emission scheduling problem of hydrothermal systems comprising several equality constraints as well as non-equality ones. The hydrothermal scheduling problem is modeled as a multi-objective problem with two objective functions as fuel cost minimization and also pollutant emission minimization. After deriving the Pareto set, the most preferred solution is determined using a fuzzy satisfying method. The thermal plants are considered with valve point effect and emission level function. Besides, this paper has taken into consideration the multi-reservoir cascaded configuration of hydro units, while the relationship considered between water discharge rate and power generated through these hydro units is nonlinear. Also, there is a water transport delay between hydro units. The presented model is implemented on a sample test system comprising four cascaded hydro units and three thermal units to verify the efficiency of the proposed method. Furthermore, the proposed method is implemented on IEEE 118 bus test case. The results obtained from the simulation show the effectiveness of the presented technique in the case of fuel cost and emission output compared to other approaches recently used.