A Fully Decentralized Approach for Solving the Economic Dispatch Problem

Abstract

A practical formulation of the economic dispatch problem is based on treating the problem as a non-convex optimization problem in which the practical non-convex cost functions are taken into consideration. Formulating the economic dispatch problem as a non-convex optimization problem and finding a better quality solution to this problem has consumed a large portion of the research for decades. Almost all previously presented solutions to the non-convex economic dispatch problem are centralized solutions. Recently, as a result of current research directions towards enabling the smart grid, a new research trend has emerged. This new research trend is to solve the economic dispatch problem using decentralized and distributed mechanisms. Among these mechanisms, the consensus on lambda approach is the best known mechanism. A drawback of this approach is that it can solve only the economic dispatch problem with convex cost functions; in addition, it lacks the appropriate mechanism for incorporating the transmission losses. This thesis presents a new decentralized approach for solving the economic dispatch problem. The proposed approach consists of either two or three stages. In the first stage, a flooding-based consensus algorithm is proposed in order to achieve consensus among the agents with respect to the units and system data. In the second stage, a suitable algorithm is used for solving the economic dispatch problem locally by each agent. For cases in which a non-deterministic method is used in the second stage, a third stage is applied to achieve consensus on the final solution of the problem, with a flooding-based consensus algorithm for sharing the information required during this stage. The required communication time by the proposed approach has been approximated using JADE software. Four case studies were examined for validation purposes. The results show that the proposed approach is highly effective for both solving the non-convex formulation of the economic dispatch problem and incorporating transmission losses accurately in a fully decentralized manner. Moreover, the proposed approach can also be applied with some adaptation to solve the economic dispatch problem with convex cost functions; in this case, it is very competitive to the consensus on lambda approach.