Standard example from CIGRE TB 601

In this example, we see how we can use linerate to compute the steady state thermal rating and the steady state conductor temperature with the conductor, span and weather parameters listed in Example B on page 79-81 of [1].

Imports and utilities

import matplotlib.pyplot as plt
import numpy as np

import linerate

Define conductor type

conductor = linerate.Conductor(
    core_diameter=10.4e-3,
    conductor_diameter=28.1e-3,
    outer_layer_strand_diameter=2.2e-3,
    emissivity=0.9,
    solar_absorptivity=0.9,
    temperature1=25,
    temperature2=75,
    resistance_at_temperature1=7.283e-5,
    resistance_at_temperature2=8.688e-5,
    aluminium_cross_section_area=float("nan"),  # No core magnetisation loss
    constant_magnetic_effect=1,
    current_density_proportional_magnetic_effect=0,
    max_magnetic_core_relative_resistance_increase=1,
)

Create towers for a span that faces east-west

start_tower = linerate.Tower(latitude=50 - 0.0045, longitude=0, altitude=500 - 88)
end_tower = linerate.Tower(latitude=50 + 0.0045, longitude=0, altitude=500 + 88)
span = linerate.Span(
    conductor=conductor,
    start_tower=start_tower,
    end_tower=end_tower,
    ground_albedo=0.15,
    num_conductors=1,
)

Create the weather data class

weather = linerate.Weather(
    air_temperature=20,
    wind_direction=np.radians(80),  # Conductor azimuth is 0, so angle of attack is 80
    wind_speed=1.66,
    clearness_ratio=0.5,
)

Setup CIGRE 601 model

time_of_measurement = np.datetime64("2016-10-03 14:00")
model = linerate.Cigre601(span, weather, time_of_measurement)

Compute line rating and temperature

max_conductor_temperature = np.linspace(26, 100, 75)
current_load = np.linspace(0, 1_000, 101)

conductor_rating = model.compute_steady_state_ampacity(max_conductor_temperature)
conductor_temperature = model.compute_conductor_temperature(current_load, tolerance=0.01)

Plot line rating and temperature

fig, axes = plt.subplots(1, 2, figsize=(8, 2.5), tight_layout=True)
axes[0].plot(max_conductor_temperature, conductor_rating, "k")
axes[0].set_xlabel(r"Max conductor temperature $[^\circ \mathrm{C}]$")
axes[0].set_ylabel(r"Ampacity rating $[\mathrm{A}]$")

axes[1].plot(current_load, conductor_temperature, "k")
axes[1].set_xlabel(r"Current $[\mathrm{A}]$")
axes[1].set_ylabel(r"Conductor temperature $[^\circ \mathrm{C}]$")

plt.show()