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Feasibility Checks

Each Line exposes three feasibility methods. All return a (bool, str) tuple — True if the constraint is satisfied, plus a descriptive message when it is not.

Ampacity Feasibility

Checks that:

  1. The conductor has sufficient capacity — ampacity exceeds the target peak current.
  2. The conductor is not grossly over-designed — ampacity is less than 3× the target peak current.

Both conditions must hold for the check to pass. This dual-bound ensures that candidates that are heavily oversized for the target power requirement are also excluded.

feasible, msg = line.is_ampacity_feasible(current_a=1300)
# (True, '')

feasible, msg = line.is_ampacity_feasible(current_a=1500)
# (False, 'Ampacity 1398 A is not sufficient for peak current 1500 A.')

# From power and voltage
feasible, msg = line.is_ampacity_feasible(power_mw=200, voltage_kv=115)
# (True, '')  — 200 MW at 115 kV ≈ 1004 A, within [ampacity/3, ampacity]

Over-designed lines are also flagged

A conductor rated for 1400 A evaluated against a 200 MW / 345 kV target (~335 A) will return False because 1400 > 335 × 3 = 1005. Choose a smaller conductor or a lower voltage for lightly loaded corridors.

Sag Feasibility

Checks that the maximum conductor sag under the given loading does not exceed max_sag_m.

feasible, msg = line.is_sag_feasible(
    current_a=1300,
    max_sag_m=10,
    initial_tension_percentage=0.3,
)

max_sag_m is required

is_sag_feasible requires an explicit max_sag_m argument. When sag feasibility is evaluated by a project (select_sag_feasible=True), the project uses line_design.max_sag_m. If that field is None, sag feasibility is skipped.

Corona Feasibility

Checks that the operating voltage does not exceed the corona inception voltage.

feasible, msg = line.is_corona_feasible(
    structure_config=my_config_ac,
    voltage_kv=230,
)
# (True, '')

feasible, msg = line.is_corona_feasible(
    structure_config=my_config_ac,
    voltage_kv=345,
)
# (False, 'Corona inception voltage 230.2 kV is below the line voltage.')

Feasibility in Projects

Projects automatically apply all three checks before reporting costs. You can control which checks run:

project.select_ampacity_feasible = True    # default
project.select_sag_feasible = True         # default (requires max_sag_m set on LineDesign)
project.select_corona_feasible = True      # default (requires structure_config on project)

Disable a check by setting its flag to False:

project.select_sag_feasible = False    # skip sag check for this project

Lines that fail any active check are silently excluded from the output. If all candidates fail, the project returns an empty result {}.