A Hopfield model to economic dispatch of power systems having special units

This paper presents a Hopfield model with three strategies to solve the economic dispatch (ED) problems having prohibited operating zones. The prohibited operating zones of a unit result in the ED problem becoming a nonconvex optimization problem; consequently there are many local minima embedded in the problem. By employing the proposed Hopfield model, one can find out the global or near global minimum for the nonconvex problem mentioned above. An energy function is defined in the proposed model. The model solution moves in the direction of decreasing energy and finally reaches an optimal point with minimum energy. Application of the proposed approach is demonstrated using a 15-unit system with 4 units having prohibited zones. In the solving process, the dispatching generation level of each unit gradually changes according to its incremental cost and runs toward the optimal value obeying the equal-incremental-cost criterion. From the results of the sample-system study, the proposed method shows its ability of solving economic dispatch considering units having prohibited operating zones.