The Research On Identification Of The Vulnerable Sections In Power System

Large scale blackouts are always related to power system weak parts. It isextremely necessary to identify vulnerable parts in power system to enhance theoperators’ awareness.The vulnerable section in power system is defined and a method of identifyingthe vulnerable sections based on the complex network theory and the spectral methodis proposed. The major work is as follows:1) Vulnerable section is defined as a section composed of several lines whosefailures will partition the system into two parts and cause large amount of powerimbalance between partitions.2) A graph model of the power grid is established with nodes connected by edges.Then, the method of identifying the vulnerable sections based on the minimum cut isproposed. Further, to avoid identifying a single line which connects a generator node,the vulnerable section is modified as the section composed of a set of lines which arestructural weak and transfer large active power.3) Three kinds of definition of weights for edges are studied and discussed: theweight based on topological structure, the weight based on electrical distance and theweight based on the electrical distance and the power flow distribution. A fast methodof identifying the vulnerable sections in power system based on the normalized cut isalso proposed. The computational complexity of this method is analyzed and themethod is proved to be fast.Finally, results on the IEEE30test system and IEEE118test system show thatthe methods of identifying the vulnerable sections based on the minimum cut and thenormalized cut are effective to identify the vulnerable sections in power system.