Short-term combined economic emission scheduling of hydrothermal systems with cascaded reservoirs using particle swarm optimization technique

This paper develops an efficient and reliable particle swarm optimization (PSO) based algorithm for solving combined economic emission scheduling of hydrothermal systems with cascaded reservoirs. A multi-chain cascaded hydrothermal system with non-linear relationship between water discharge rate, power generation and net head is considered in this paper. The water transport delay between connected reservoirs is also considered. The problem is formulated considering both cost and emission as competing objectives. Combined economic emission scheduling (CEES) is a bi-objective problem. A price penalty factor approach is utilized here to convert this bi-objective CEES problem into a single objective one. The effect of valve-point loading is also taken into account in the present problem formulation. The feasibility of the proposed method is demonstrated on a sample test system consisting of four cascaded hydro units and three thermal units. The results of the proposed technique based on PSO are compared with other evolutionary programming method. It is found that the results obtained by the proposed technique are superior in terms of fuel cost, emission output etc. It is also observed that the computation time is considerably reduced by the proposed technique based on PSO. (C) 2010 Elsevier B.V. All rights reserved.