Dynamic Security Analysis Research Based On Dynamic Security Regions Theory

With the expansion of power system and increasing of interrelated parts, it is gradually important to how to confirm secure operation of power system, and economical operation under secure condition. So the security analysis of power system, especially dynamic security Analysis(DSR), becomes the research's emphasis and focus increasingly.The dynamic security analysis can confirm real-time secure operation of power system, and meet equation and inequality, which belongs to dispatch automation's area. During the long period of time, the security analysis and transient stability, which are synthesized gradually, aim to equation and inequality from dispatch automation and power system stability respectively for reasearch, so the concepts of two parts are confused. I think, in broad sense, the dynamic security analysis of power system is divided into transient stability analysis (TSA), voltage stability analysis(VSA),frequency stability analysis (FSA). The first one aims to power balance, and the other two to voltage and frequency stability. Nowadays the transient stability analysis(TSA) has been mature relatively. So in some sense, the dynamic security analysis covers more broadly. The methods and theories that are introduced in this paper aim to TSA.The paper proposes a ANN dynamic security analysis theory based on dynamic security regions, which includes hyper-plane imitation based on BP network and fuzzy theory, ANN dynamic security regions methods composed by two-kind orthree-kind classifier for running points classification and stability margins imitator for stability margins computation, adaptive ANN method for multi-fault of power system, and especially a optimization for injections of bulk power system. The optimization based on optimal feature subset of decision tables and element discretization of rough-set is used to select feature elements, which is regarded as ANN injection features, from the lager dimensions injections. The 'dimensions misfortune' problem caused by application of ANN dynamic security regions method to bulk power system is solved fairly because of injection features reduction. The validity of the optimization is proved by simulation on power systems. The main content of paper is introduced as follows.In chapter one and two, the present conditions on dynamic security analysis are introduced, especially the present conditions, existing and resolved problems of power system dynamic security analysis based on dynamic security regions theory are analyzed and researched.In chapter three, the imitation based on BP network and fuzzy method, which replaces the traditional least square method to imitate the practical dynamic security regions, is presented to the relatively low accuracy of traditional hyper-plane method.In chapter four, the ANN dynamic security regions method is proposed including two-kind or three-kind classifier for running points classification and stability margins imitator for stability margins computation. The method overcomes the deficiency of hyper-plane imitation extensively, such as reduction of misjudgments because of hyper-plane theory itself limitation, and difficulty to decide accurately security margins of running points.In chapter five, the optimization of injection is raised to avoid 'dimensionsmisfortune' in bulk system. The method enhances the validity of ANN dynamic security analysis largely.In chapter six, the adaptive ANN method is put forwards for multi-fault of power system. The method overcomes the deficiency of ANN dynamic security-regions method, which can only build a network to a fault. So the quantities of ANN are reduced largely.In chapter seven, the research prospect on dynamic security analysis theory is introduced and analyzed.