Identification Method of Vulnerable Lines in Power System Based on the Comprehensive Evaluation System

A few fragile lines in the power system are prone to cause cascading failures, so it is urgent to study how to identify them. However, the existing identification methods of fragile lines only study the structural characteristics or operating state of the power network, and do not comprehensively consider the structural vulnerability and state vulnerability. Therefore, this paper establishes an evaluation system for the vulnerability of lines as the basis for identifying vulnerable lines: the active power transmission betweenness index is defined from the structure level, the impact index of power flow transfer entropy is constructed from the operation state level, and the overload risk index to measure the local impact of line disconnection is proposed. Besides, based on IEEE39 system, the network transmission efficiency index is used to measure the connectivity and transmission capacity of the system after disconnection attack, and disconnection simulation is conducted to evaluate and verify the effectiveness of the vulnerability assessment system. The example shows that the evaluation system for the vulnerability of lines in this paper is scientific, and the identification results of vulnerable lines through comprehensive vulnerability are more convincing.