Load-Frequency Control in a Deregulated Environment Based on Bisection Search

Recently several robust control designs have been proposed to the load-frequency control (LFC) problem. However, the importance and difficulties in the selection of weighting functions of these approaches and the pole-zero cancellation phenomenon associated with it produces closed loop poles. Also the order of robust controllers is as high as the plant. This gives rise to complex structure of such controllers and reduces their applicability in industry. In addition conventional LFC systems that use classical or trial-and-error approaches to tune the PI controller parameters are more difficult and time-consuming to design. In this paper, a bisection search method is proposed to design well-tuned PI controller in a restructured power system based on the bilateral policy scheme. The bisection search is a very simple and rapidly converging method in mathematics. It is a root-finding approach which repeatedly bisects an interval and then selects a subinterval in which a root must lie for further processing. The new optimized solution performance has been applied to a 3-area restructured power system with possible contracted scenarios under large load demand and area disturbances. The results evaluation shows the proposed method achieves good performance compared with a powerful robust ILMI-based controller. Moreover, this newly developed solution has a simple structure, and is fairly easy to implement in comparison to other controllers, which can be useful for the real world complex power systems.