Application Of Intelligent Control Theoretic In HVDC System

"Interconnection in the whole country, transmission electric power from West to East and exchange electric power between South and North" is the necessary stratagem of our power industry. High voltage direct current (HVDC) transmission systems, which are fit for transmission electric power in long distance and large capability, will be one style of the Interconnection in power network and be widely applied in our country. This paper focuses on the design of HVDC controllers and the problem of the coordination among the controllers in the multi-infeed AC/DC systems.At present, the control method in HVDC systems is still the typical control theory. The actual AC/DC mixed systems are typical nonlinear and time-varying systems, however, the classic controllers have difficulty in guaranteeing systems' normal running in any times. This paper focuses on the applying of the fuzzy logic control and ANN network theory in HVDC control system., combined with the traditional control theory. New basic controller and additional controller are designed in this paper.The traditional controllers have disadvantage in adaptability and robust, for this reason this paper combines the advantages of the traditional PI controllers and ANN network controllers, and designs signal ANN adaptive PID controller for constant current mode. The controller's structure is simple, and easy to come true. The simulation results indicate effectiveness and superiorities of the new controller.The coordination among the controllers in multi-infeed DC systems is very important. For an AC/DC system that includes two DC lines, based on fuzzy logic theory two fuzzy additional controllers are designed, and the parameters areoptimized with NETOMAC software. Simulation results show that the controllers can improve the transient stability of AC/DC system.