Transmission Line Model

Defines a reusable transmission-line model (single- or three-phase, PI or Bergeron, entered via surge-impedance / RLC / sequence / matrix data). Placed on the canvas as a definition box with a unique name; Transmission Line Terminals reference it by name. Contributes nothing to the simulation itself — the math is realized by the synthetic Tline that is assembled when two terminals sharing a line name are paired.

Category: Transmission

Ports

This component has no wired ports — see Named inputs / outputs below if any.

Parameters

Config

Name	Label	Type	Default	Units	Description
model_name	Model name	string	TL1	—	Unique identifier for this transmission-line model. Terminals select it by name. Two models sharing a name is an error (typically a copy/paste mistake) and blocks the run.
number_of_conductors	Conductors	enum (1 / 3)	1	—	Number of conductors. 1 = single-phase (one electrical node per terminal); 3 = three-phase (one electrical_3ph node per terminal). More counts are future work.
data_entry_1ph	Data entry	enum (Bergeron — Surge Impedance / Bergeron — RLC / PI — RLC / Physical (coming soon))	berg_zc	—	How the single-phase line is parameterized. Bergeron entries give a travelling-wave model; PI gives a lumped nominal-pi section. All forms reduce to the same canonical R/L/C.
data_entry_3ph	Data entry	enum (Bergeron — Sequence Surge Impedance / Bergeron — Sequence RLC / Bergeron — Balanced Matrix / PI — Sequence RLC / PI — Balanced Matrix / Physical (coming soon))	berg_seq_z	—	How the three-phase line is parameterized. Sequence / matrix data is reduced to positive- and zero-sequence canonical R/L/C.

Bergeron Parameters

Name	Label	Type	Default	Units	Description
zc	Zc (Ω)	double	400	—	Surge / characteristic impedance.
tau	τ (travel time)	double	100	usec (s, ms, µs)	One-way travel time of the line.

RLC Parameters

Name	Label	Type	Default	Units	Description
length	Length (km)	double	100	—	Line length in km. Per-km R/L/C are multiplied by this to get the line totals.
r_per_len	R	double	0.05	ohmkm (Ω/km, Ω/m, pu/km)	Series resistance per unit length. Choose pu/km to enter book per-unit data (e.g. Kundur r); the value is converted with Z_base = V_base² / S_base from the Units tab.
l_per_len	L	double	0.000001	Hm (H/m, H/km, mH/km, µH/km, pu/km)	Series inductance per unit length (default 1e-6 H/m = 1 mH/km). With pu/km the value is read as series reactance per km (book xL) in per-unit: L = x·Z_base / (2π·Freq).
c_per_len	C	double	1e-11	Fm (F/m, F/km, mF/km, µF/km, pu/km)	Shunt capacitance per unit length (default 1e-11 F/m = 0.01 µF/km). With pu/km the value is read as shunt susceptance per km (book bc) in per-unit: C = b / (Z_base·2π·Freq).

Sequence Surge Impedance

Name	Label	Type	Default	Units	Description
z1	Z1 (Ω)	double	350	—	Positive-sequence surge impedance.
tau1	τ1 (travel time)	double	100	usec (s, ms, µs)	Positive-sequence one-way travel time.
z0	Z0 (Ω)	double	550	—	Zero-sequence surge impedance.
tau0	τ0 (travel time)	double	130	usec (s, ms, µs)	Zero-sequence one-way travel time.

Sequence RLC

Name	Label	Type	Default	Units	Description
seq_length	Length (km)	double	100	—	Line length in km.
r1_per_len	R1	double	0.03	ohmkm (Ω/km, Ω/m, pu/km)	Positive-sequence series resistance per unit length. Choose pu/km to enter book per-unit data (e.g. Kundur r); converted with Z_base = V_base² / S_base from the Units tab.
l1_per_len	L1	double	9e-7	Hm (H/m, H/km, mH/km, µH/km, pu/km)	Positive-sequence series inductance per unit length (default 9e-7 H/m = 0.9 mH/km). With pu/km the value is read as positive-sequence series reactance per km (book xL) in per-unit: L1 = x·Z_base / (2π·Freq).
c1_per_len	C1	double	1.2e-11	Fm (F/m, F/km, mF/km, µF/km, pu/km)	Positive-sequence shunt capacitance per unit length (default 1.2e-11 F/m = 0.012 µF/km). With pu/km the value is read as positive-sequence shunt susceptance per km (book bc) in per-unit: C1 = b / (Z_base·2π·Freq).
r0_per_len	R0	double	0.3	ohmkm (Ω/km, Ω/m, pu/km)	Zero-sequence series resistance per unit length. Choose pu/km to enter book per-unit data; converted with Z_base = V_base² / S_base from the Units tab.
l0_per_len	L0	double	0.0000026	Hm (H/m, H/km, mH/km, µH/km, pu/km)	Zero-sequence series inductance per unit length (default 2.6e-6 H/m = 2.6 mH/km). With pu/km the value is read as zero-sequence series reactance per km in per-unit: L0 = x·Z_base / (2π·Freq).
c0_per_len	C0	double	8e-12	Fm (F/m, F/km, mF/km, µF/km, pu/km)	Zero-sequence shunt capacitance per unit length (default 8e-12 F/m = 0.008 µF/km). With pu/km the value is read as zero-sequence shunt susceptance per km in per-unit: C0 = b / (Z_base·2π·Freq).

Balanced Matrix

Name	Label	Type	Default	Units	Description
mat_length	Length (km)	double	100	—	Line length in km.
rs_ohm	Rs (Ω)	double	3	—	Total per-phase series resistance (self).
ls_per_len	Ls	double	0.0000015	Hm (H/m, H/km, mH/km, µH/km)	Self inductance per unit length (diagonal of L matrix; default 1.5e-6 H/m = 1.5 mH/km).
lm_per_len	Lm	double	5.7e-7	Hm (H/m, H/km, mH/km, µH/km)	Mutual inductance per unit length (off-diagonal of L matrix; default 5.7e-7 H/m = 0.57 mH/km). L1 = Ls − Lm, L0 = Ls + 2·Lm.
cs_per_len	Cs	double	1.1e-11	Fm (F/m, F/km, mF/km, µF/km)	Self capacitance per unit length (diagonal of Maxwell C matrix; default 1.1e-11 F/m = 0.011 µF/km).
cm_per_len	Cm	double	1e-12	Fm (F/m, F/km, mF/km, µF/km)	Mutual capacitance per unit length (magnitude of off-diagonal; default 1e-12 F/m = 0.001 µF/km). C1 = Cs + Cm, C0 = Cs − 2·Cm.

Units

Name	Label	Type	Default	Units	Description
S_base	S_base (MVA)	double	100	—	System base apparent power in MVA. Used by `pu` impedance / admittance conversions in this component's `computations` block.
V_base	V_base (kV)	double	230	—	Base RMS line-to-line voltage in kV. Used by `pu` impedance / admittance conversions in this component's `computations` block.
Freq	Frequency (Hz)	double	60	—	Frequency in Hz. Used by `B` (susceptance) / `X` (reactance) conversions in this component's `computations` block.

Used in samples

• BergeronDemo
• TlineDemo
• SimpleAC