Line¶
Create Function¶
Lines can be either created from the standard type library (create_line) or with custom values (create_line_from_parameters).
Note
Lines for 3 phase load flow uses zero sequence parameters which can be provided through a custom standard type using pandapower.create_std_type() and pandapower.add_zero_impedance_parameters()
Zero sequence parameters (Added through std_type For Three phase load flow) :
r0_ohm_per_km (float)  zero sequence line resistance in ohm per km
x0_ohm_per_km (float)  zero sequence line reactance in ohm per km
c0_nf_per_km (float)  zero sequence line capacitance in nano Farad per km
 pandapower.create_line(net, from_bus, to_bus, length_km, std_type, name=None, index=None, geodata=None, df=1.0, parallel=1, in_service=True, max_loading_percent=nan, alpha=nan, temperature_degree_celsius=nan, **kwargs)¶
Creates a line element in net[“line”] The line parameters are defined through the standard type library.
 INPUT:
net  The net within this line should be created
from_bus (int)  ID of the bus on one side which the line will be connected with
to_bus (int)  ID of the bus on the other side which the line will be connected with
length_km (float)  The line length in km
std_type (string)  Name of a standard linetype :
Predefined in standard_linetypes
or
Customized std_type made using create_std_type()
 OPTIONAL:
name (string, None)  A custom name for this line
index (int, None)  Force a specified ID if it is available. If None, the index one higher than the highest already existing index is selected.
geodata (array, default None, shape= (,2L))  The linegeodata of the line. The first row should be the coordinates of bus a and the last should be the coordinates of bus b. The points in the middle represent the bending points of the line
in_service (boolean, True)  True for in_service or False for out of service
df (float, 1)  derating factor: maximal current of line in relation to nominal current of line (from 0 to 1)
parallel (integer, 1)  number of parallel line systems
max_loading_percent (float)  maximum current loading (only needed for OPF)
alpha (float)  temperature coefficient of resistance: R(T) = R(T_0) * (1 + alpha * (T  T_0)))
temperature_degree_celsius (float)  line temperature for which line resistance is adjusted
tdpf (bool)  whether the line is considered in the TDPF calculation
wind_speed_m_per_s (float)  wind speed at the line in m/s (TDPF)
wind_angle_degree (float)  angle of attack between the wind direction and the line (TDPF)
conductor_outer_diameter_m (float)  outer diameter of the line conductor in m (TDPF)
air_temperature_degree_celsius (float)  ambient temperature in °C (TDPF)
reference_temperature_degree_celsius (float)  reference temperature in °C for which r_ohm_per_km for the line is specified (TDPF)
solar_radiation_w_per_sq_m (float)  solar radiation on horizontal plane in W/m² (TDPF)
solar_absorptivity (float)  Albedo factor for absorptivity of the lines (TDPF)
emissivity (float)  Albedo factor for emissivity of the lines (TDPF)
r_theta_kelvin_per_mw (float)  thermal resistance of the line (TDPF, only for simplified method)
mc_joule_per_m_k (float)  specific mass of the conductor multiplied by the specific thermal capacity of the material (TDPF, only for thermal inertia consideration with tdpf_delay_s parameter)
 OUTPUT:
index (int)  The unique ID of the created line
 EXAMPLE:
create_line(net, “line1”, from_bus = 0, to_bus = 1, length_km=0.1, std_type=”NAYY 4x50 SE”)
 pandapower.create_line_from_parameters(net, from_bus, to_bus, length_km, r_ohm_per_km, x_ohm_per_km, c_nf_per_km, max_i_ka, name=None, index=None, type=None, geodata=None, in_service=True, df=1.0, parallel=1, g_us_per_km=0.0, max_loading_percent=nan, alpha=nan, temperature_degree_celsius=nan, r0_ohm_per_km=nan, x0_ohm_per_km=nan, c0_nf_per_km=nan, g0_us_per_km=0, endtemp_degree=nan, **kwargs)¶
Creates a line element in net[“line”] from line parameters.
 INPUT:
net  The net within this line should be created
from_bus (int)  ID of the bus on one side which the line will be connected with
to_bus (int)  ID of the bus on the other side which the line will be connected with
length_km (float)  The line length in km
r_ohm_per_km (float)  line resistance in ohm per km
x_ohm_per_km (float)  line reactance in ohm per km
c_nf_per_km (float)  line capacitance (linetoearth) in nano Farad per km
r0_ohm_per_km (float)  zero sequence line resistance in ohm per km
x0_ohm_per_km (float)  zero sequence line reactance in ohm per km
c0_nf_per_km (float)  zero sequence line capacitance in nano Farad per km
max_i_ka (float)  maximum thermal current in kilo Ampere
 OPTIONAL:
name (string, None)  A custom name for this line
index (int, None)  Force a specified ID if it is available. If None, the index one higher than the highest already existing index is selected.
in_service (boolean, True)  True for in_service or False for out of service
type (str, None)  type of line (“ol” for overhead line or “cs” for cable system)
df (float, 1)  derating factor: maximal current of line in relation to nominal current of line (from 0 to 1)
g_us_per_km (float, 0)  dielectric conductance in micro Siemens per km
g0_us_per_km (float, 0)  zero sequence dielectric conductance in micro Siemens per km
parallel (integer, 1)  number of parallel line systems
geodata (array, default None, shape= (,2L))  The linegeodata of the line. The first row should be the coordinates of bus a and the last should be the coordinates of bus b. The points in the middle represent the bending points of the line
max_loading_percent (float)  maximum current loading (only needed for OPF)
alpha (float)  temperature coefficient of resistance: R(T) = R(T_0) * (1 + alpha * (T  T_0)))
temperature_degree_celsius (float)  line temperature for which line resistance is adjusted
tdpf (bool)  whether the line is considered in the TDPF calculation
wind_speed_m_per_s (float)  wind speed at the line in m/s (TDPF)
wind_angle_degree (float)  angle of attack between the wind direction and the line (TDPF)
conductor_outer_diameter_m (float)  outer diameter of the line conductor in m (TDPF)
air_temperature_degree_celsius (float)  ambient temperature in °C (TDPF)
reference_temperature_degree_celsius (float)  reference temperature in °C for which r_ohm_per_km for the line is specified (TDPF)
solar_radiation_w_per_sq_m (float)  solar radiation on horizontal plane in W/m² (TDPF)
solar_absorptivity (float)  Albedo factor for absorptivity of the lines (TDPF)
emissivity (float)  Albedo factor for emissivity of the lines (TDPF)
r_theta_kelvin_per_mw (float)  thermal resistance of the line (TDPF, only for simplified method)
mc_joule_per_m_k (float)  specific mass of the conductor multiplied by the specific thermal capacity of the material (TDPF, only for thermal inertia consideration with tdpf_delay_s parameter)
 OUTPUT:
index (int)  The unique ID of the created line
 EXAMPLE:
create_line_from_parameters(net, “line1”, from_bus = 0, to_bus = 1, lenght_km=0.1, r_ohm_per_km = .01, x_ohm_per_km = 0.05, c_nf_per_km = 10, max_i_ka = 0.4)
Input Parameters¶
net.line
Parameter 
Datatype 
Value Range 
Explanation 
name 
string 
name of the line 

std_type 
string 
standard type which can be used to easily define line parameters with the pandapower standard type library 

from_bus* 
integer 
Index of bus where the line starts 

to_bus* 
integer 
Index of bus where the line ends 

length_km* 
float 
\(>\) 0 
length of the line [km] 
r_ohm_per_km* 
float 
\(\geq\) 0 
resistance of the line [Ohm per km] 
x_ohm_per_km* 
float 
\(\geq\) 0 
inductance of the line [Ohm per km] 
c_nf_per_km* 
float 
\(\geq\) 0 
capacitance of the line (linetoearth) [nano Farad per km] 
r0_ohm_per_km**** 
float 
\(\geq\) 0 
zero sequence resistance of the line [Ohm per km] 
x0_ohm_per_km**** 
float 
\(\geq\) 0 
zero sequence inductance of the line [Ohm per km] 
c0_nf_per_km**** 
float 
\(\geq\) 0 
zero sequence capacitance of the line [nano Farad per km] 
g_us_per_km* 
float 
\(\geq\) 0 
dielectric conductance of the line [micro Siemens per km] 
max_i_ka* 
float 
\(>\) 0 
maximal thermal current [kilo Ampere] 
parallel* 
integer 
\(\geq\) 1 
number of parallel line systems 
df* 
float 
0…1 
derating factor (scaling) for max_i_ka 
type 
string 
Naming conventions:
“ol”  overhead line
“cs”  underground cable system

type of line 
max_loading_percent** 
float 
\(>\) 0 
Maximum loading of the line 
endtemp_degree*** 
float 
\(>\) 0 
ShortCircuit end temperature of the line 
in_service* 
boolean 
True / False 
specifies if the line is in service. 
*necessary for executing a balanced power flow calculation
**optimal power flow parameter
***shortcircuit calculation parameter
****
necessary for executing a three phase power flow / single phase short circuit
.. note:
Defining a line with length zero leads to a division by zero in the power flow and is therefore not allowed. Lines with a very low impedance might lead to convergence problems in the power flow
for the same reason. If you want to directly connect two buses, please use the switch element instead of a line with a small impedance!
net.line_geodata
Parameter 
Datatype 
Explanation 
coords 
list 
List of (x,y) tuples that mark the inflexion points of the line 
Electric Model¶
Lines are modelled with the \(\pi\)equivalent circuit:
Three phase line model
The elements in the equivalent circuit are calculated from the parameters in the net.line dataframe as:
The power system frequency \(f\) is defined when creating an empty network, the default value is \(f = 50 Hz\).
Note
For three phase load flow, three decoupled sequence networks ( zero , positive and negtive) are considered.
Positive and Negative sequence impedances are given by r_ohm_per_km, x_ohm_per_km, and c_nf_per_km
Zero sequence impedances are given by r0_ohm_per_km, x0_ohm_per_km, and c0_nf_per_km
The parameters are then transformed in the per unit system:
Where the reference voltage \(V_{N}\) is the nominal voltage at the from bus and the rated apparent power \(S_{N}\) is defined system wide in the net object (see Unit Systems and Conventions).
Note
pandapower assumes that nominal voltage of from bus and to bus are equal, which means pandapower does not support lines that connect different voltage levels. If you want to connect different voltage levels, either use a transformer or an impedance element.
Result Parameters¶
net.res_line
Parameter 
Datatype 
Explanation 
p_from_mw 
float 
active power flow into the line at “from” bus [MW] 
q_from_mvar 
float 
reactive power flow into the line at “from” bus [MVar] 
p_to_mw 
float 
active power flow into the line at “to” bus [MW] 
q_to_mvar 
float 
reactive power flow into the line at “to” bus [MVar] 
pl_mw 
float 
active power losses of the line [MW] 
ql_mvar 
float 
reactive power consumption of the line [MVar] 
i_from_ka 
float 
Current at from bus [kA] 
i_to_ka 
float 
Current at to bus [kA] 
i_ka 
float 
Maximum of i_from_ka and i_to_ka [kA] 
vm_from_pu 
float 
voltage magnitude at from bus 
vm_to_pu 
float 
voltage magnitude at to bus 
va_from_degree 
float 
voltage angle at from bus [degrees] 
va_to_degree 
float 
voltage angle at to bus [degrees] 
loading_percent 
float 
line loading [%] 
The power flow results in the net.res_line table are defined as:
net.res_line_3ph
Parameter 
Datatype 
Explanation 
p_a_from_mw 
float 
active power flow into the line at from bus: Phase A [MW] 
q_a_from_mvar 
float 
reactive power flow into the line at from bus : Phase A[MVar] 
p_b_from_mw 
float 
active power flow into the line at from bus: Phase B [MW] 
q_b_from_mvar 
float 
reactive power flow into the line at from bus : Phase B[MVar] 
p_c_from_mw 
float 
active power flow into the line at from bus: Phase C [MW] 
q_c_from_mvar 
float 
reactive power flow into the line at from bus : Phase C[MVar] 
p_a_to_mw 
float 
active power flow into the line at to bus: Phase A [MW] 
q_a_to_mvar 
float 
reactive power flow into the line at to bus : Phase A[MVar] 
p_b_to_mw 
float 
active power flow into the line at to bus: Phase B [MW] 
q_b_to_mvar 
float 
reactive power flow into the line at to bus : Phase B[MVar] 
p_c_to_mw 
float 
active power flow into the line at to bus: Phase C [MW] 
q_c_to_mvar 
float 
reactive power flow into the line at to bus : Phase C[MVar] 
pl_a_mw 
float 
active power losses of the line: Phase A [MW] 
ql_a_mvar 
float 
reactive power consumption of the line: Phase A [MVar] 
pl_b_mw 
float 
active power losses of the line: Phase B [MW] 
ql_b_mvar 
float 
reactive power consumption of the line: Phase B [MVar] 
pl_c_mw 
float 
active power losses of the line: Phase C [MW] 
ql_c_mvar 
float 
reactive power consumption of the line: Phase C [MVar] 
i_a_from_ka 
float 
Current at from bus: Phase A [kA] 
i_b_from_ka 
float 
Current at from bus: Phase B [kA] 
i_c_from_ka 
float 
Current at from bus: Phase C [kA] 
i_n_from_ka 
float 
Current at from bus: Neutral [kA] 
i_a_to_ka 
float 
Current at to bus: Phase A [kA] 
i_b_to_ka 
float 
Current at to bus: Phase B [kA] 
i_c_to_ka 
float 
Current at to bus: Phase C [kA] 
i_n_to_ka 
float 
Current at to bus: Neutral [kA] 
i_ka 
float 
Maximum of i_from_ka and i_to_ka [kA] 
loading_percent 
float 
line loading [%] 
The power flow results in the net.res_line_3ph table are defined as:
net.res_line_est
The state estimation results are put into net.res_line_est with the same definition as in net.res_line.
Parameter 
Datatype 
Explanation 
p_from_mw 
float 
active power flow into the line at “from” bus [MW] 
q_from_mvar 
float 
reactive power flow into the line at “from” bus [MVar] 
p_to_mw 
float 
active power flow into the line at “to” bus [MW] 
q_to_mvar 
float 
reactive power flow into the line at “to” bus [MVar] 
pl_mw 
float 
active power losses of the line [MW] 
ql_mvar 
float 
reactive power consumption of the line [MVar] 
i_from_ka 
float 
Current at from bus [kA] 
i_to_ka 
float 
Current at to bus [kA] 
i_ka 
float 
Maximum of i_from_ka and i_to_ka [kA] 
vm_from_pu 
float 
voltage magnitude at from bus 
vm_to_pu 
float 
voltage magnitude at to bus 
va_from_degree 
float 
voltage angle at from bus [degrees] 
va_to_degree 
float 
voltage angle at to bus [degrees] 
loading_percent 
float 
line loading [%] 