tmp.py

import numpy as np
import pandas as pd


def calcul_chute_tension(
    Ib=1, S=1.5, Un=400, L=0.1, metal="cuivre", phi=np.arccos(0.85)
):

    Ib = np.asarray(Ib)
    S = np.asarray(S)

    R_const = 22.5 if metal == "cuivre" else 36
    R = (S < 500).astype(np.float64) * R_const
    X = (S > 50).astype(np.float64) * 0.08

    results = {}
    for i in Ib:
        delta_Un = np.sqrt(3) * i * L * (R / S * np.cos(phi) + X * np.sin(phi))
        delta_Un_perc = 100 * delta_Un / Un
        results[i] = delta_Un_perc

    results = pd.DataFrame(results, index=S)
    results.columns = results.columns.rename("Ib")
    results.index = results.index.rename("S")
    return results