Optimal Load Frequency Control of Multi-Area Power System Considering Incremental Control Action

For an economic and reliable operation of a power system, electrical power generation-demand balance must be sustained online. In modern power systems with multiple interconnected control areas (CA), altering the generation-demand does not only affect the system frequency but also leads to undesired deviations in power flows between CAs. To avert the catastrophic failure of the entire system, generation must always balance out the load demand so as to maintain frequency and tie-line power within prescribed limit. Thus, load frequency control (LFC), achieved by adjusting the MW outputs of generators, is applied. In this paper, model predictive control (MPC) based LFC in multi-area power system (MAPS) is presented. It is aimed at maintaining frequency of each CA and tie-line power within given limits. The conventional LFC is modified to consider the effect of incremental control action, in addition to the system dynamic constraints like generation rate constraint (GRC). The effectiveness of the proposed scheme is verified through time-based simulations on 8-generator, 4-area MAPS subjected to multiple load disturbances. The responses of the system is compared with traditional PID controller. The results reveal efficacy of the proposed scheme with 26.79% and 25.12% improvement of settling time and overshoot respectively over the PID controller.