from linerate.equations import (
cigre207,
convective_cooling,
dimensionless,
math,
solar_angles,
solar_heating,
)
from linerate.equations.math import switch_cos_sin
from linerate.models.thermal_model import ThermalModel, _copy_method_docstring
from linerate.types import Span, Weather
from linerate.units import Ampere, Celsius, Date, OhmPerMeter, WattPerMeter
[docs]
class Cigre207(ThermalModel):
def __init__(
self,
span: Span,
weather: Weather,
time: Date,
include_diffuse_radiation: bool = True,
direct_radiation_factor: float = 1.0,
):
super().__init__(span, weather)
self.time = time
self.include_diffuse_radiation = include_diffuse_radiation
self.direct_radiation_factor = direct_radiation_factor
[docs]
@_copy_method_docstring(ThermalModel)
def compute_joule_heating(
self, conductor_temperature: Celsius, current: Ampere
) -> WattPerMeter:
return super().compute_joule_heating(
conductor_temperature=conductor_temperature, current=current
)
[docs]
@_copy_method_docstring(ThermalModel)
def compute_solar_heating(
self, conductor_temperature: Celsius, current: Ampere
) -> WattPerMeter:
alpha_s = self.span.conductor.solar_absorptivity
phi = self.span.latitude
gamma_c = self.span.conductor_azimuth
y = self.span.conductor_altitude
D = self.span.conductor.conductor_diameter
omega = solar_angles.compute_hour_angle_relative_to_noon(self.time, self.span.longitude)
delta = solar_angles.compute_solar_declination(self.time)
sin_H_s = solar_angles.compute_sin_solar_altitude(phi, delta, omega)
chi = solar_angles.compute_solar_azimuth_variable(phi, delta, omega)
C = solar_angles.compute_solar_azimuth_constant(chi, omega)
gamma_s = solar_angles.compute_solar_azimuth(C, chi) # Z_c in IEEE
cos_eta = solar_angles.compute_cos_solar_effective_incidence_angle(
sin_H_s, gamma_s, gamma_c
)
sin_eta = switch_cos_sin(cos_eta)
I_B = self.direct_radiation_factor * cigre207.solar_heating.compute_direct_solar_radiation(
sin_H_s, y
)
if self.include_diffuse_radiation:
I_d = cigre207.solar_heating.compute_diffuse_sky_radiation(I_B, sin_H_s)
F = self.span.ground_albedo
else:
I_d = 0
F = 0
I_T = cigre207.solar_heating.compute_global_radiation_intensity(
I_B, I_d, F, sin_eta, sin_H_s
)
return solar_heating.compute_solar_heating(
alpha_s,
I_T,
D,
)
[docs]
@_copy_method_docstring(ThermalModel)
def compute_convective_cooling(
self, conductor_temperature: Celsius, current: Ampere
) -> WattPerMeter:
D = self.span.conductor.conductor_diameter
d = self.span.conductor.outer_layer_strand_diameter
V = self.weather.wind_speed
y = self.span.conductor_altitude
T_a = self.weather.air_temperature
T_c = conductor_temperature
T_f = 0.5 * (T_c + T_a)
# Compute physical quantities
lambda_f = cigre207.convective_cooling.compute_thermal_conductivity_of_air(T_f)
nu_f = cigre207.convective_cooling.compute_kinematic_viscosity_of_air(T_f)
delta = math.compute_angle_of_attack(
self.weather.wind_direction, self.span.conductor_azimuth
)
# Compute unitless quantities
rho_r = cigre207.convective_cooling.compute_relative_air_density(y)
Re = cigre207.convective_cooling.compute_reynolds_number(V, D, nu_f, rho_r)
Gr = dimensionless.compute_grashof_number(D, T_c, T_a, nu_f)
Pr = cigre207.convective_cooling.compute_prandtl_number(T_f)
Rs = dimensionless.compute_conductor_roughness(D, d)
# Compute nusselt numbers
Nu_90 = cigre207.convective_cooling.compute_perpendicular_flow_nusseltnumber(
reynolds_number=Re, conductor_roughness=Rs
)
Nu_delta = cigre207.convective_cooling.correct_wind_direction_effect_on_nusselt_number(
Nu_90, delta
)
Nu_cor = cigre207.convective_cooling.compute_low_wind_speed_nusseltnumber(Nu_90)
Nu_0 = cigre207.convective_cooling.compute_horizontal_natural_nusselt_number(Gr, Pr)
Nu = cigre207.convective_cooling.compute_nusselt_number(
forced_convection_nusselt_number=Nu_delta,
natural_nusselt_number=Nu_0,
low_wind_nusselt_number=Nu_cor,
wind_speed=V,
)
return convective_cooling.compute_convective_cooling(
surface_temperature=conductor_temperature,
air_temperature=self.weather.air_temperature,
nusselt_number=Nu,
thermal_conductivity_of_air=lambda_f,
)
[docs]
@_copy_method_docstring(ThermalModel)
def compute_radiative_cooling(
self, conductor_temperature: Celsius, current: Ampere
) -> WattPerMeter:
return super().compute_radiative_cooling(
conductor_temperature=conductor_temperature, current=current
)
[docs]
@_copy_method_docstring(ThermalModel)
def compute_resistance(self, conductor_temperature: Celsius, current: Ampere) -> OhmPerMeter:
return super().compute_resistance(
conductor_temperature=conductor_temperature, current=current
)