EMISSION CONSTRAINED DYNAMIC DISPATCH

Since the early 1970s thermal generation dispatch has been proposed as an effective means of dealing with the problem of air pollution. More restrictive recent legislation has led to the adoption of pollution-limiting techniques and/or the use of less polluting fuels. An emission constrained dispatch, however, is still required either when contingent difficulties in the availability of low pollutant fuels occur or in the presence of meteorological conditions adverse to the diffusion of effluents. In this paper a dynamic dispatch procedure is proposed which is capable of taking into account the integral nature of the emission constraints. The mixing of fuels with different pollution rates and the management of multifuel plants are taken into account with the purpose of obtaining a cost-effective operation for all thermal plants in compliance with emission limitations. A suitably modified version of the Han-Powell algorithm is employed to find a solution for the resulting large-scale nonlinear programming problem. A method is considered to obtain a suboptimal solution of the mixed integer nonlinear programming problem which arises when emission control is achieved by switching from one fuel to another. Tests on a small CIGRE network and on a medium-sized EHV Italian system are presented to validate the proposed procedures.