Assessment of suitability of different reliability importance measures for prioritising replacement of transmission system components

The paper presents a comparison of four widely used reliability importance measures in order to identify their appropriateness for the identification of the most critical system components for replacement planning; specifically when using Non-sequential Monte Carlo method. These importance measures are Improvement Potential, Structural Importance, Criticality Importance, and Fussell-Vesely Importance. The four reliability importance measures were calculated for each system component (power transformer in this particular study) and then components were ranked separately based on each measure. Then, the components were replaced, one by one starting from the most critical, to establish the relationship between the replacement according to each ranking and the overall system reliability. The study was performed on a realistic transmission network containing 154 transformers. The results of the paper proved that Improvement Potential is the most appropriate importance measure for replacement planning.