Process maintenance#

given:
  parameters:
    Process_p_nom_extendable: { dims: [process], dtype: bool }
    Process_p_nom_min: { dims: [scenario, process] }
    Process_p_nom_max: { dims: [scenario, process] }
    Process_committable: { dims: [process], dtype: bool }
    Process_p_nom_mod: { dims: [process] }
    Process_modules_installed: { dims: [scenario, process] }
    Process_active: { dims: [snapshot, process], dtype: bool }
    snapshot_weightings_generators: { dims: [snapshot] }
  variables:
    Process_status: { dims: [scenario, snapshot, process], domain: integer }
    Process_p_nom_ext: { dims: [process] }
  conditions:
    Process_committed: { dims: [process, snapshot] }

dimensions:
  scenario:
    description: the futures dispatch is chosen in, each with a weight
  snapshot:
    description: dispatch periods
    dtype: datetime
    ordered: true
  process:
    description: generalised multi-port converters, each with an internal power that every port draws or delivers at its own rate

relations:
  Process_maintenance_cover:
    description: >-
      the snapshots a maintenance event covers, by the snapshot it starts in,
      data prep. In a scenario, they are the start and the snapshots after it,
      until their generator weightings reach that scenario's
      `maintenance_duration`. A process that is not maintainable has no rows
    dims: { scenario: scenario, process: process, start: snapshot, covered: snapshot }
    missing: absent

parameters:
  Process_maintainable:
    description: >-
      whether a process must be taken off for maintenance within the horizon:
      in any scenario, as PyPSA takes the union over them
      (`components.py:1000-1003`)
    dims: [process]
    dtype: bool
  Process_maintenance_pu:
    description: the share of the build a maintenance event takes off
    dims: [scenario, process]
  Process_maintenance_events:
    description: how many maintenance events occur within the horizon
    dims: [scenario, process]
    dtype: int
  Process_maintenance_duration:
    description: >-
      the hours of generator weightings one maintenance event covers, PyPSA's
      `maintenance_duration`. It has no value where the process is not
      maintainable. No row contains it. In data prep you turn it into
      `Process_maintenance_cover` and `Process_maintenance_start_blocked`. The
      assumptions state that it fits the horizon
    dims: [scenario, process]
    missing: absent
  Process_maintenance_start_blocked:
    description: >-
      true where no maintenance event may start, data prep. The snapshots it
      would cover there run past the end of the horizon or into one the
      process is not active in. It is PyPSA's `active & ~valid`, from
      `maintenance_duration` and the generator weightings
    dims: [scenario, snapshot, process]
    dtype: bool

variables:
  Process_maintenance:
    description: >-
      `Process-maintenance` — whether a maintainable process is in maintenance:
      continuous, and one exactly where an event covers the snapshot
    dims: [scenario, snapshot, process]
    where: Process_maintainable AND Process_active
    missing: 0
    bounds:
      lower: 0
      upper: 1
  Process_maintenance_start:
    description: "`Process-maintenance_start` — whether a maintenance event starts in this snapshot"
    dims: [scenario, snapshot, process]
    where: Process_maintainable AND Process_active
    missing: 0
    domain: binary
  Process_maintenance_capacity:
    description: >-
      `Process-maintenance_capacity` — the chosen build while in maintenance,
      zero otherwise: the product the `maintcap` rows linearise
    dims: [scenario, snapshot, process]
    where: Process_maint_ext
    missing: 0
    bounds:
      lower: 0
  Process_maintenance_status:
    description: >-
      `Process-maintenance_status` — the status while in maintenance, zero
      otherwise: the product the `maint-status` rows linearise, so a unit in
      maintenance may also be off
    dims: [scenario, snapshot, process]
    where: >-
      Process_maintainable
      AND Process_committed
      AND NOT (Process_p_nom_extendable AND NOT (Process_p_nom_mod > 0))
    missing: 0
    bounds:
      lower: 0

expressions:
  Process_maintenance_modules:
    description: >-
      how many modules of a modular committable process can be on in
      maintenance: its build cap in modules where the build is extendable,
      and the modules installed where it is fixed (`constraints.py:588-594`)
    dims: [scenario, process]
    cases:
      extendable: { when: Process_p_nom_extendable, expression: Process_p_nom_max / Process_p_nom_mod }
    otherwise: Process_modules_installed

conditions:
  Process_maint_ext:
    description: >-
      a maintainable process with an extendable build that is active in the
      snapshot's period, unless it is committable and modular. These are the
      maintenance rows against the chosen build
    condition: >-
      Process_maintainable
      AND Process_p_nom_extendable
      AND NOT (Process_committable AND Process_p_nom_mod > 0)
      AND Process_active

constraints:
  Process_maint_event_count:
    description: "`Process-maint-event-count` — a maintainable process holds its number of maintenance events over the horizon"
    dims: [scenario, process]
    where: Process_maintainable
    expression: sum(Process_maintenance_start, over=snapshot) == Process_maintenance_events
  Process_maint_window:
    description: >-
      `Process-maint-window` — a process is in maintenance exactly where an
      event it started covers the snapshot. Two events do not overlap, since
      the maintenance status is at most one
    dims: [scenario, snapshot, process]
    where: Process_maintainable AND Process_active
    expression: Process_maintenance == sum(Process_maintenance_start, over=start, by=Process_maintenance_cover[covered])
  Process_maint_start_horizon:
    description: "`Process-maint-start-horizon` — no event starts where it could not run its whole duration"
    dims: [scenario, snapshot, process]
    where: Process_maintainable AND Process_active AND Process_maintenance_start_blocked
    expression: Process_maintenance_start == 0
  Process_maintcap_upper:
    description: >-
      `Process-maintcap_upper` — the build taken off is at most the chosen build in
      maintenance, and at most the build less its floor out of it
    dims: [scenario, snapshot, process]
    where: Process_maint_ext
    expression: Process_maintenance_capacity <= Process_p_nom_ext - Process_p_nom_min * (1 - Process_maintenance)
  Process_maintcap_upper_nommax:
    description: "`Process-maintcap_upper_nommax` — out of maintenance, no build is taken off"
    dims: [scenario, snapshot, process]
    where: Process_maint_ext
    expression: Process_maintenance_capacity <= Process_p_nom_max * Process_maintenance
  Process_maintcap_lower_nommax:
    description: "`Process-maintcap_lower_nommax` — in maintenance, the whole chosen build is taken off"
    dims: [scenario, snapshot, process]
    where: Process_maint_ext
    expression: Process_maintenance_capacity >= Process_p_nom_ext - Process_p_nom_max * (1 - Process_maintenance)
  Process_maintcap_lower_nommin:
    description: "`Process-maintcap_lower_nommin` — in maintenance, at least the floor of the build is taken off"
    dims: [scenario, snapshot, process]
    where: Process_maint_ext AND Process_p_nom_min > 0
    expression: Process_maintenance_capacity >= Process_p_nom_min * Process_maintenance
  Process_maint_status_le_status:
    description: "`Process-maint-status-le-status` — the status in maintenance is at most the status"
    dims: [scenario, snapshot, process]
    where: Process_maintainable AND Process_committed AND NOT Process_p_nom_extendable AND NOT (Process_p_nom_mod > 0)
    expression: Process_maintenance_status <= Process_status
  Process_maint_status_le_maint:
    description: "`Process-maint-status-le-maint` — out of maintenance, the status in maintenance is zero"
    dims: [scenario, snapshot, process]
    where: Process_maintainable AND Process_committed AND NOT Process_p_nom_extendable AND NOT (Process_p_nom_mod > 0)
    expression: Process_maintenance_status <= Process_maintenance
  Process_maint_status_lb:
    description: "`Process-maint-status-lb` — on and in maintenance, the status in maintenance is one"
    dims: [scenario, snapshot, process]
    where: Process_maintainable AND Process_committed AND NOT Process_p_nom_extendable AND NOT (Process_p_nom_mod > 0)
    expression: Process_maintenance_status >= Process_status + Process_maintenance - 1
  Process_maint_modstatus_le_status:
    description: "`Process-maint-modstatus-le-status` — the modules on in maintenance are at most the modules on"
    dims: [scenario, snapshot, process]
    where: Process_maintainable AND Process_committed AND Process_p_nom_mod > 0
    expression: Process_maintenance_status <= Process_status
  Process_maint_modstatus_le_maint:
    description: >-
      `Process-maint-modstatus-le-maint` — out of maintenance, no module is on
      in maintenance. In it, at most its modules in maintenance
    dims: [scenario, snapshot, process]
    where: Process_maintainable AND Process_committed AND Process_p_nom_mod > 0
    expression: Process_maintenance_status <= Process_maintenance_modules * Process_maintenance
  Process_maint_modstatus_lb:
    description: "`Process-maint-modstatus-lb` — in maintenance, every module on is on in maintenance"
    dims: [scenario, snapshot, process]
    where: Process_maintainable AND Process_committed AND Process_p_nom_mod > 0
    expression: Process_maintenance_status >= Process_status - Process_maintenance_modules * (1 - Process_maintenance)

assumptions:
  Process_maintenance_events_positive:
    holds: "Process_maintenance_events > 0"
    where: "Process_maintainable"
    description: >-
      a maintainable process with no event schedules no maintenance. PyPSA
      refuses it (`consistency.py:1541`)
  Process_maintenance_duration_positive:
    holds: "Process_maintenance_duration > 0"
    where: "Process_maintainable"
    description: >-
      an event that covers no hours is no maintenance window. PyPSA refuses it
      (`consistency.py:1531`)
  Process_maintenance_duration_fits_the_horizon:
    holds: "Process_maintenance_duration <= sum(snapshot_weightings_generators, over=snapshot)"
    where: "Process_maintainable"
    description: >-
      one event longer than the horizon, in generator weightings, blocks every
      start and makes the event count infeasible. PyPSA refuses it
      (`consistency.py:1552`)
  Process_maintenance_events_fit_the_horizon:
    holds: "Process_maintenance_duration * Process_maintenance_events <= sum(snapshot_weightings_generators, over=snapshot)"
    where: "Process_maintainable"
    description: >-
      the events together longer than the horizon, in generator weightings,
      cannot all be scheduled. PyPSA refuses it (`consistency.py:1564`)
  Process_maintenance_build_cap_is_finite:
    holds: "Process_p_nom_max < inf"
    where: "Process_maintainable AND Process_p_nom_extendable"
    description: >-
      the `maintcap` rows bound the chosen build in maintenance by
      `p_nom_max`, so an infinite cap is an infinite coefficient. PyPSA
      refuses it (`consistency.py:1576`)