Research Of Line Vulnerability On Power System Cascading Failures

Power system is the key infrastructure for the national economy and people’s life. At present, the scale of power system becomes larger and larger and the structure of power system becomes more and more complex. Power system faces multiple risks such as structure, information and so on. In the structure, these blackouts often start with a component or a line malfunctioning, and will lead to other components and lines out of operation. The rapid spread of the cascading failures eventually led to the collapse of power system.Several typical models were studied base on the theory of complex network in this paper. Firstly, the role of complex network in power system was analyzed and brittleness theory was introduced. Based on the example of faults in power system at home and abroad, the mechanism of cascading failures was explained briefly and the effect of bad weather on the occurrence of accidents was analyzed.In this paper, we put forward a comprehensive index of capacity margin and the rate of change of line capacity. The algorithm of identifying vulnerable lines was given. The value of vulnerability was used to identify the line vulnerability, and a new model of vulnerability assessment of power network was established. Then, the application of the IEEE9 node system proved the validity of the identification method.Due to the establishment of vulnerability assessment, this paper studied the method of reducing the line vulnerability. Then, the method of directional cutting machine and load was compared with traditional methods. Finally, the IEEE9 node system was used to verify the accuracy of the method. According to the results of fault simulation, failure mechanism of large-scale power system and mitigation strategies were analyzed.