A risk assessment method based on importance of component and operational state under catastrophic accident

To consider the importance of components and time-varying operational conditions comprehensively, a risk assessment method, based on operational reliability and entropy, is investigated for catastrophic accident of power system. Real-time fault probability is got by using component´s operational reliability model which considers the cumulative effect, and component´s importance is obtained by using the combination of entropy and potential energy, which takes active power, reactive power and other factors into account. Finally, on the basis of fault probability, component´s importance and severity, considering both operational state and structure change simultaneously, a catastrophic accident risk index is built to predict the risk of each level in multilevel fault cases, which reflects the process from cascading outages to catastrophic accident. Simulation results on the IEEE 57-bus system, for instance, the rank of N-1 initial fault risk and N-k fault sequence risk assessment prove that this method can identify the risks within the system effectively.