Reliability Assessment of 500kV Substation Based on Fault Tree Analysis

Substation is the important element in a power grid, its reliability is critical to the secure and stable operation of large power grid. In this paper, the fault tree analysis method in probabilistic risk assessment is used to analyze the power supply reliability of a 500kV substation, taking the insufficient power supply to the 220kV power grid as the undesired event. The fault tree describes the disruption of the transmission of energy from the power supply to the transformer. The fault combinations leading to the undesired event can be obtained by calculating the Minimum Cut Sets (MCSs) of fault tree, and quantitative reliability assessment was carried out by calculating the failure probability of undesired events based on the component reliability model and data. In addition, dominate failure contributions based on component importance measures is adopted for the weak parts identification in substation. Quantitative evaluation of the fault tree, which represents a understanding of the power supply reliability from the 500KV substation to 220kV grid, which can identify the most important components in the substation, and provide a scientific basis for power system planning, equipment reliability s Selection election and maintenance optimization.