Line struct
#include <gtopt/line.hpp>
Represents a transmission line (branch) connecting two buses.
A line carries active power flow f ∈ [-tmax_ba, tmax_ab] between bus_a and bus_b. In Kirchhoff mode the flow is constrained by f = V² / X · (θ_a − θ_b) where V is the line voltage and X the reactance. When voltage is omitted (defaults to 1.0) both V and X are in per-unit; when voltage is in kV, reactance must be in Ω. Optional expansion variables allow the solver to invest in additional transfer capacity.
Public functions
- auto line_losses_mode_enum() const -> constexpr std::optional<LineLossesMode> noexcept
- Parse line_losses_mode string to enum (nullopt = inherit from global).
- auto loss_allocation_mode_enum() const -> constexpr LossAllocationMode noexcept
- Parse loss_allocation_mode string to enum (receiver if unset).
Public variables
- OptActive active
- Activation status (default: active)
- OptTRealFieldSched annual_capcost
- Annualized investment cost [$/MW-year].
- OptTRealFieldSched annual_derating
- Annual capacity derating factor [p.u./year].
- SingleId bus_a
- Sending-end (from) bus ID.
- SingleId bus_b
- Receiving-end (to) bus ID.
- OptTRealFieldSched capacity
- Installed transfer capacity [MW].
- OptTRealFieldSched capmax
- Absolute maximum capacity after expansion [MW].
- OptTRealFieldSched expcap
- Capacity added per expansion module [MW].
- OptTRealFieldSched expmod
- Maximum number of expansion modules [dimensionless].
- OptName line_losses_mode
- OptName loss_allocation_mode
- OptInt loss_segments
- OptTRealFieldSched lossfactor
- Lumped loss factor [p.u.].
- Name name
- Line name.
- OptTRealFieldSched phase_shift_deg
- OptTRealFieldSched reactance
- OptTRealFieldSched resistance
- OptTRealFieldSched tap_ratio
- OptTRealFieldSched tcost
- Variable transmission cost [$/MWh].
- OptTBRealFieldSched tmax_ab
- Maximum power flow in A→B direction [MW].
- OptTBRealFieldSched tmax_ba
- Maximum power flow in B→A direction [MW].
- OptName type
- Optional line type tag (e.g. "ac", "dc", "transformer")
- Uid uid
- Unique identifier.
- OptBool use_line_losses deprecated
- OptTRealFieldSched voltage
Variable documentation
OptName gtopt::
Loss model selection (per-line override). See LineLossesMode for valid values: "none", "linear", "piecewise", "bidirectional", "adaptive", "dynamic". When unset, inherits from ModelOptions.
OptName gtopt::
How losses are allocated between sender and receiver buses: "receiver" (default), "sender", or "split" (50/50, PLP default).
OptInt gtopt::
Number of piecewise-linear segments for quadratic losses (default: from Options)
OptTRealFieldSched gtopt::
Phase-shift angle [degrees]. Models a phase-shifting transformer (PST) by adding a constant angle offset φ to the Kirchhoff equality constraint: f = B_eff · (θ_a − θ_b − φ). Positive values reduce the natural power flow from bus_a to bus_b. Defaults to 0.0.
OptTRealFieldSched gtopt::
Series reactance for DC power flow [Ω]. Use p.u. when voltage is omitted (default). Susceptance: B = V² / X.
OptTRealFieldSched gtopt::
Series resistance [Ω]. Use p.u. when voltage is omitted.
OptTRealFieldSched gtopt::
Off-nominal tap ratio [p.u.]. For transformers only; ignored for plain lines. When set to a value other than 1.0 the effective susceptance of the branch in the DC power-flow (Kirchhoff) constraint is scaled by 1/tap_ratio, i.e. B_eff = V²/(tap_ratio · X). Defaults to 1.0 (nominal tap, no correction).
OptBool gtopt::
OptTRealFieldSched gtopt::
Nominal voltage level [kV]. Omit or set to 1.0 for per-unit mode.