The coupling surface#

The surface every other file in the library is written against. It declares one Port_p per port, one balance per bus, and the relation that says which bus a port sits on. Nothing in it names a component class, so it is the one file that does not change when a component class is added.

PyPSA gives each component class a bus column and sums the classes into Bus-nodal_balance. Here a component is wired to a port and the port to a bus, so the balance sums ports and stays as written however many fragments merge. The how-to guide shows the same shape with fewer names.

A flow is positive where the port injects into its bus. Every component reads that convention, and no component restates it.

description: >-
  The coupling surface every component in this library is written against: one
  flow per port, and one balance per bus. A component is wired to a port, the
  port to a bus, and the balance names no component class. A flow is positive
  where the port injects into its bus.
dimensions:
  snapshot: { dtype: datetime, description: dispatch periods }
  bus: { dtype: str, description: network nodes }
  port: { dtype: str, description: "the connections components make, one label per connection" }
relations:
  Port_bus: { key: port, values: bus }
variables:
  Port_p:
    dims: [snapshot, port]
    description: what a port puts into its bus in a snapshot, negative for a withdrawal
constraints:
  Bus_nodal_balance:
    description: "`Bus-nodal_balance` — what the ports on a bus put in nets to nothing"
    dims: [snapshot, bus]
    expression: sum(Port_p, by=Port_bus, over=port, into=bus) == 0

The coupling surface every component in this library is written against: one flow per port, and one balance per bus. A component is wired to a port, the port to a bus, and the balance names no component class. A flow is positive where the port injects into its bus.

Sets#

Variables#

Subject to#

Bus_nodal_balance

Variable domains#

Port_p