Study On The Chaotic Motion Of Power System And Its Control Method

As an important research direction of nonlinear science, chaotic theory has already infiltrated to such as power system, encryption communication, medical science and many other areas, which effectively promotes the development of these subjects. In smart grid, grid-connected system of renewable energy access to smart distribution grid leads to a series of serious consequences to the stability of the system. This article researches on the bifurcation and chaos phenomena and its generating mechanism in power system, especially in smart distribution grid. In order to suppress chaotic oscillation, a controller is designed. This provides theoretical basis for improve power quality and enhance stability of the system.This thesis studies on the problems of bifurcation and chaos in power systems. Analyze some classical chaotic power system models, research on the creation conditions for different types of bifurcation and the relations between bifurcation and chaos. Analyze commonly used research methods of chaotic dynamics and then apply these methods to practical models to prove their effectiveness.In view of the incomprehensibility of actual model, this thesis uses phase space reconstruction method to detect chaos in power system. On the premise of time series data is known, research on the evaluating methods of delay time and embedding dimension with examples. Use C-C method to realize phase space reconstruction and chaotic motion detection of a complicated power system. The result proves the effectiveness of the proposed method.Analyze the operation state variation process and the operation state variation mechanism of smart distribution grid. In modeling process, the inverter is regarded as the interface between renewable energy and infinite power and the load model is dynamic. Discuss the process of operation states vary from stable, bifurcation, chaos, hyperchaos and eventually occur voltage collapse. Find out the internal relations among these operation states. Study on the security operation level and the measures should be taken with the corresponding operation state.Build generalized fuzzy hyperbolic model (GFHM) of the smart distribution grid and then design a network H∞ controller based on event-triggered algorithm.In order to reduce the burden of the transmission network and improve the efficiency of information transmission, a novel event-triggered algorithm is presented. Under this algorithm, only those sampling signals which satisfy the constraint can be released to the network. A system model contains time-delay is established; on this basis an event-triggered Hoo network controller is designed. The stability conditions of the controller’s H∞ norm bound and its design method are given. The results show that this controller greatly reduces the release rate of the sampling signals and achieves perfect effect when the GFHM of the smart distribution grid is regarded as controlled member.