Modeling Assumptions Base Case Topology Base case topology refers to how system Elements are represented and linked together for the year(s) to be studied.System Elements modeled in base cases include, but are not limited to transmission lines, transformers, series and shuntElements in New England, generators on the New England transmission system, merchant transmission facilities in New England, and similar topology for adjacent systems. There are a number of Tariff and practical considerations that determine the topology used for various types of planning studies. For example, Needs Assessments and Solutions Studies need to include the facilities that have a commitment to be available (e.g. an obligation in the Forward Capacity Market, a reliability upgrade with an approved PPA or a merchant facility with an approved PPA and an associated binding contract) and need to exclude projects that are not committed to be available. For System Impact Studies the studies need to include all active generators in the FERC section of the ISO queue that have earlier (higher) queue positions. The starting point for the development of a base case is ISO’s Model on Demand database which includes a model of the external system from the Multiregional Modeling Working Group (MMWG). This Model on Demand data base is used to create ISO’s portion of the MMWG base case. However, the Model on Demand data base is updated periodically to include update and newly approved projects.Table 21 summarizes the topology used in planning studies Table Base Case Topology Study Transmission in New England Generation in New England Merchant Facilities Transmission outside New England Generation outside New England PPA Study ofransmission roject (Steady State and Stability) In-Service, Under Construction, and Planned (1) In-Service, Under Construction or has an approved PPA (1)(7) In-Service, Under Construction or has an approved PPA Models fromrecent MMWG base case Models from recent MMWG base case System Impact Study (Steady State and Stability) In-Service, Under Construction, and Planned (1) In-Service, Under Construction, or has an approved PPA or is included in FERC section of the ISO queue (1)(7) In-Service, Under Construction or has an approved PPA Models from recentMMWG base case Models fromrecent MMWG base case
Table Generator Maximum Power in Planning Studies Type of Study SteadyState Stability Conventional Generation Fast Start Generation Hydro (1) Generation Wind Generation Solar (2) Generation PPA Study of Transmission Project X X NRC Sum NRC Win NRC Sum NRC Win NRC Sum NRC Win NRC Sum NRC Win NRC Sum NRC Win System Impact Study X X NRC Sum NRC Win NRC Sum NRC Win NRC Sum NRC Win NRC Sum NRC Win NRC Sum NRC Win Transmission Needs Assessment X QC Sum QC Sum Historical Level 5% of nameplate for wind (3) QC Sum Transmission Solutions Study X QC Sum QC Sum Historical Level 5% of nameplate for wind (3) QC Sum Transmission Solutions Study X NRC Win NRC Win NRC Win NRC Win NRC Win Area Review Analyses X X NRC Sum NRC Win NRC Sum NRC Win NRC Sum NRC Win NRC Sum NRC Win NRC Sum NRC Win BPS Testing Analyses X X NRC Sum NRC Win NRC Sum NRC Win NRC Sum NRC Win NRC Sum NRC Win NRC Sum NRC Win Transfer Limit Studies X X NRC Sum NRC Win NRC Sum NRC Win NRC Sum NRC Win NRC Sum NRC Win NRC Sum NRC Win Interregional Studies X X NRC Sum NRC Sum NRC Sum NRC Sum NRC Sum FCM New Resource Qualification Overlapping Impact Analyses X CNRC Sum CNRC Sum CNRC Sum CNRC Sum CNRC Sum FCM New Resource Qualification Network Resource Interconnection Standard Analyses X NRC Sum NRC Sum NRC Sum NRC Sum NRC Sum FCM Study for Annual Reconfiguration Auctions and Annual CSO Bilaterals X Lower of QC Sum or CSO Lower of QC Sum or CSO Lower of QC Sum or CSO Lower of QC Sum or CSO Lower of QC Sum or CSO FCM Delist Analyses X QC Sum QC Sum QC Sum QC Sum QC Sum Transmission Security Analyses X QC Sum QC Sum QC Sum QC Sum QC Sum Capacity Deferral Notifications X Lower of QC Sum or CSO Lower of QC Sum or CSO Lower of QC Sum or CSO Lower of QC Sum or CSO Lower of QC Sum or CSO