Studies On Boundary Characteristic And Rapid Constructing Method Of Wide Area Security Region For Electric Power System

With the development of the economy in China, the contradiction between supply and demand of electrical power system is being aggravated constantly. In order to resolve the imbalance problem of energy distribution and economic development, power grids should transport more and more electricity from long-distance area to the economy centers. Because of vast energy consumption, the ecological environment has been severely damaged. Meanwhile clean energy is growing rapidly, and wind and solar energy were plugged into the grid. Huge power plants and ultra-high-voltage lines have been built to satisfy the social increasing demand, and the connection among interconnected power grids is being strengthened. Therefore, studies on security and stability of interconnected power grids are of great importance.A method for forming wide area security region about interconnected power grids has been studied and discussed in this thesis. Features of the security region boundary are also analyzed, and a comprehensive method to fast form such security region is proposed. Main work of this thesis is as follows:1) With considering features of the interconnected power grids, a wide area security region is proposed, which is constructed on the space of exchange active powers of some important interfaces in the grid. Since the number of such interfaces is very few, dimensions of the security region will be lower. Hence the security region could be determined quickly. A rapid determining method to the boundary of security region is then given, in which information of the critical points on the boundary and curve fitting algorithm are utilized.2) Base on the theory of security region and with considering the thermal limits of the interfaces, a thermal security region is proposed. Normal vector of the critical point on the region's boundary is adopted to determine segments of the boundary. And numerical simulation method was used to determine the exact critical points. Based on that, a comprehensive method to rapidly determine thermal security region is proposed.3) Based on the academic researches, software to calculate the thermal security region is developed. Some useful functions, such as data import/export, data fitting, critical point searching, GUI and visualization to the security region are embedded to the software.Researches and software developed in this thesis have been applied to a real bulk power system in Southern China, feasibility and effectiveness have been validated.