Probabilistic reliability assessment of North American Electric Power Systems

This paper summarizes the results of the first mandatory NERC wide probabilistic reliability assessment that was completed in 2012. The main purpose of the assessment is to complement NERC´s 2012 long-term reliability assessment (LTRA) by providing additional probabilistic metrics such as the expected unserved energy (EUE) and the loss of load expectation expressed in terms of hours per year (LOLH). The reliability of 26 assessment areas was examined in 11 individual evaluations which varied in scope from large interconnected systems such as the Western Electricity Coordinating Council (WECC) to relatively smaller systems for example Manitoba Hydro. These individual assessments were then combined into NERC´s 2012 ProbA for the entire NERC footprint. The reliability indices for the third (2014) and the fifth (2016) years from the 2012 LTRA were calculated and reported for each assessment area. The assumptions, methodologies and models used in the 2012 ProbA are briefly described. Suggestions are also made for the improvement in the future NERC wide probabilistic reliability assessment.