SOME CONSIDERATIONS ON OPF AND AGC CO-ORDINATION

The control of electric power systems is structured in hierarchical levels. At the optimising level, the value of control variables which optimises some economical criterion is computed, while all constraints are met and a foreseen load is supplied. At the directcontrol level, setpoints for active generated powers and for generating voltagesare determined so as to track the load demand that rapidly changes. The aim of our studyis to find a methodology to compare different choices of time frames in which thecontrol actions are executed, while stressing the need for a close co-ordination between the different levels of control. The paper tries to highlight the effects of the choice ofoptimising action solving frequency and of co-ordination between optimising and direct control levels on operational costs and on smoothness of control action.