Study On Self-organized Criticality Of Power System Blackouts

The electric power is the national fundamental energy and the economic lifeline and the security, high quality power supplies concerns national economy and the people's livelihood. However, a series of large blackouts have occurred in China and abroad since the 1960s, which caused huge social economy loss. In the traditional analysis method, the detailed mathematical model of each component in the system should be established firstly. then, the giant-dimensional differential-algebraic equations is built and simulated by computer to study evolutionary mechanism of the blackouts. But, this method is lack of macro mechanism when deeply analyze evolutionary mechanism of the power system blackouts. It has been unable to explain macro mechanism of the power system blackouts and inherent and regular intrinsic characteristic of power system.In recent years, complexity science studying on complex system and system complexity has been formated and paid much attention at home and abroad. The complexity science takes system overall characteristic as object of study. Especially, complexity system demonstrates self-organized criticality (SOC) is its inherent characteristic in the evolution of the systems. From macro aspect, the complexity science theory and method of self-organized criticality is applied to explore blackouts of power systems in this dissertation. The main work is as follows.The phenomenon of SOC and the power-law relationship in complex system are introduced. By analyzing the statistics data in the China power grid, the power-law between the scale of power failure and frequency is first discovered in China. It shows that the blackout has SOC characteristics in China power grid. It laid the foundation for further studies on the characteristic of the power accidents.Two SOC-Power Failure models that used to simulate power system evolutionary are given in the paper. They are more suitable than OPA model in power dispatching. Simulation results prove that the SOC in power systems. The paper also presents the scheduling policy of both the degree of overall system load level and the slope for each component load factor in double logarithmic plot are important in power grid operating.By applying the theory of cellular automata in the evolutionary mechanism of the power system blackouts, the model of CA-Power Failure is given in the paper. The model defines the composition method of cellular, cellular space, rules, and neighbors and so on. The evolution of the spread of power failure is researched and the SOC of the power grid by the simulation of CA-Power model is verified.The complex network is also an important area of complexity science. In this paper, the network features data of several major power grids in our country in the year of 1991 and 1998 are calculated by using the theory of complex networks. The results proved that these major power grids with a small-world network characteristics and scale-free properties. the network structure parameters of power grid and the effect on the SOC are analyzed.By application of the SOC of power system and extreme value analysis theory, it is proved that the limit of the size extreme value distribution of the blackouts based on the scale-frequency power-law distribution is convergent to the formula of I. Based on the reality power data, the calculation of extremes analysis of the blackouts data is given in the paper. This will provide the basis for the decision-making of the power system planning and demonstrate an important application prospect of SOC of power system.