UNIT COMMITMENT IN THERMAL POWER-SYSTEMS WITH LONG-TERM ENERGY CONSTRAINTS

This paper describes a method for the unit commitment considering energy constraints obtained from a long-term optimisation. In many electrical utilities there exists the problem of fulfilling energy supply contracts with other utilities or with fuel suppliers. Furthermore, the energy prices may change during the year or depend on the consumed electric energy. The presented method solves this complex task in two steps. The first step calculates a long-term e.g. yearly operation schedule with daily energies allocated to each unit. These daily energy constraints of the long-term optimisation have to be incorporated in the second step - the daily unit commitment. Special attention is given to the coordination between long-term and short-term optimisation. © 1990 IEEE