A multi-area approach to the economic optimization of electric power system

Abstract

In this paper, the problem of short-term economic dispatch of active power in a combined hydro-thermal electric power system is considered. The problem studied is a 24 hours optimization, with operational cost as associated criterion. It is assumed that consumer's demand, defined as a number of time functions, as well as technical constraints concerning power production units, and transmission line capabilities are satisfied within the period of optimization. The deterministic time discrete mathematical model of the above stated problem consists of a set of nonlinear algebraic equations and a set of nonequalities. The power system is decomposed into a number of interconnected power areas. Consequently, a number of local less dimensional area optimization subproblems are defined. Each of them is a typical nonlinear programming problem. Coordination among subproblem solutions is performed by a higher level decision making effort. It is done by specially derrived coordination algorithm. It is shown that the proposed multi-area approach is computationally effective and fast. This property has a particular importance since in practice the system under control is influenced by frequent structural disturbances (failures of production units and/or transmission lines) causing power generation rescheduling. Using the presented algorithm a short term dynamic optimization problem of 220 kV network of Serbia has been solved. The results of this solution are also discussed in the paper.