Traditional transmission reliability assessments are performed separately from operational assessments such as production cost modeling (PCM) studies that analyze future generation dispatch and transmission system congestion. Additionally, transmission reliability assessments currently consider only a few peak, off-peak, and shoulder operating conditions to identify system risks. Particularly as system penetration of variable renewable generation and electrification of end-use processes increases, this process can be inadequate. The traditional approach may fail to capture stressed operating conditions, and the system dispatch used for modeling the selected few operating conditions may not be reflective of actual future conditions.
Linking PCM studies with transmission reliability assessments can help transmission planners identify reinforcement options that can benefit both reliability as well as system operating costs. As such, an integrated planning process that links PCM assessment with power flow studies is important. This is highlighted in EPRI's Integrated Strategic System Planning (ISSP) initiative.
Linking transmission system reliability assessments with PCM studies requires transmission planners to analyze PCM study results to screen for possible stressed operating conditions and create power flow cases that are reflective of those operating conditions. While this can be a time intensive process requiring an understanding of screening methods and creating automated processes for linking the tools used for transmission reliability analysis and PCM studies, it is a critical step in the overall integrated planning process. This technical report documents the screening methods and processes that were used as a part of the ISSP initiative to link power flow analysis to PCM study results to evaluate transmission system reliability and better understand potential reinforcement options for robust planning.