A Reliability-Based Evaluation and Critical Infrastructure Identification Method for Multistate Electric Power System

As modern society increasingly relies on the stable operation of the electric power system (EPS), it is essential to evaluate the performance of the EPS and identify the critical infrastructure to ensure a reliable power supply. Since infrastructures of the EPS, including power plants, substations, and transmission lines, can operate at multiple power capacity levels due to failures or maintenance, the power capacity should be seen as multistate. In this way, the EPS is modeled as the multistate electric power network (MEPN) where power plants, substations, and transmission lines are denoted as sources, nodes, and branches, respectively. Supply reliability, defined as the probability that the MEPN can satisfy demand, is served as a performance index to measure the MEPN capability. To calculate supply reliability, an algorithm is developed based on the concept of lower power capacity patterns. Furthermore, a process called infrastructure importance measurement is introduced to systematically analyze the impact of individual infrastructure failures on supply reliability to rank the most critical infrastructure. In particular, those components in each infrastructure are not required to be identical, enhancing its applicability to the real-world system. A practical EPS in Taiwan is illustrated to provide feasibility for the system manager to evaluate the MEPN supply reliability and identify the critical infrastructures.