Cooperative control of interconnected power system load-frequency based on differential games

Load frequency control (LFC) is a key issue in the interconnected power systems, which constantly requires other control areas (CA) to share the regulation burden of the CA that is lack of regulation capacity, by providing the power supports via the tie-line. Such a process imposes extra regulation costs on the helping CAs, e.g., the wear and tear of generating units, which may result in the unfairness and the CAs´ deviation from the LFC command. This situation becomes even more serious with the integration of intermittent renewable energy such as wind and solar power. In this paper, cooperative control based on differential games (DG) is proposed as a possible solution to this problem. In particular, we derive a noncooperative equilibrium solution and a cooperative equilibrium solutions. The case studies compare the proposed two DG-based cooperative control schemes with the traditional approaches based on proportional-integral (PI) control and optimal control; and the results show that the cooperative control schemes allocate the regulation burden persuasively and guarantee the CAs´ conformity of the LFC command; whereas, using the traditional methods, the CAs tend to violate the command.