Power system risk assessment based on cascading failures and malfunction scene selection

With the development of power system and the emerging of power market, the operation of power network is closer to its limit than before. The security and reliability assessments for cascading failures of the power system are important and necessary. However, the system malfunction scenes are not possible evaluated wholly if multiple failures are considered. This paper presents a new approach to assess the system risk based on cascading failures firstly. This approach associates the occurrence probability of cascading failures with their damage on power system. The load conditions, the change of bus voltage and line flow are considered too. Secondly, malfunction scenes based on cascading failures are screened and selected according to the system risk evaluation results. At last, a practical 220kV Taiyuan power system in Shanxi Province of China has been analyzed to illustrate the proposed technique.