Linkages

Linkages serve two purposes:

  1. To connect two Components together

  2. To store data related to the linked components (e.g., the ZoneToTransmissionPath linkage holds information about which zone is the from_zone and which is the to_zone)

Hint

For folks familiar with databases, you can think of linkages as “foreign keys”.

Linkages are defined within each of the component tabs in the UI. They are specified individually for each component and is defined in the first few columns of each component. Below is an example of where linkages are in the UI

Example of select ThermalResource linkages in the Thermal Tab in the UI. Thermal Tab's Linkages

Linkage CSV File Format

Linkage input CSVs follow a slightly modified version of the attributes.csv file format discussed on the Components page. In particular, individual “instances” of linkages are not separated into separate CSV files but are instead grouped together under the same CSV file under the corresponding data/system subfolder. As such, individual linkages are identified via additional columns in the CSV file:

component_from

component_to

timestamp

attribute

value

scenario tag (optional)

[component instance name]

[component instance name]

[None or timestamp (hour beginning)]

[attribute name defined in code]

[value]

[scenario name]

Otherwise, timeseries data, units, and scenario tagging behave the same way as Component attributes.csv files.

Special Cases

Threeway Relationships

PRM → Resource → ELCC

Three-way relationships (e.g., PRM → Resource → ELCC) must be defined as multiple linkages (e.g., PRM → Resource, Resource → ELCC, ELCC → PRM) to capture all the requisite information.

Resource → Candidate Fuel → Emissions