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 Generation in Transmission Generation Transmission in New Merchant Study New England outside New outside New England Facilities England England In-Service, PPA Study In-Service, In-Service, Under Under Models ofransmission Under Models from Construction, and Construction or fromrecent roject Construction or recent MMWG Planned (1) has an MMWG base (Steady State and has an base case approved PPA case Stability) approved PPA (1)(7) In-Service, Under Construction, or In-Service, In-Service, Under System Impact Models has an Under Models from Study Construction, and fromrecent approved PPA Construction or recentMMWG (Steady State and Planned (1) MMWG base or is included in has an base case Stability) case FERC section of approved PPA the ISO queue (1)(7)
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
planning_techincal_guide_rev2_0_2017_09_25_draft.docx