Case study: reliability of the INEL-Site Power System

Recent power outages at the EG&G Idaho National Engineering Laboratory (INEL) prompted some customers to call for major modifications to the power system. The reliability of the INEL-Site Power System (a loop configuration) was analyzed to understand the true performance of the system and the dominant causes of outages. This was done using fault-tree modeling along with the IRRAS-PC computer code. Twenty-nine years of site-specific data were obtained from logbooks maintained by the INEL-Site Power System dispatch office. A detailed model was developed and validated against outage history for the site. The fault-tree analysis identified several major contributors to the outage frequency. It is shown that the fault-tree analysis technique provides a flexible and useful method for quantifying the system unreliability and identifying the major contributions to it. The model accurately describes the overall, INEL-Site Power System (INEL-SPS) performance and can easily be used to quantify the anticipated change in reliability due to potential modifications in the system