Line capacity calculation in simplify_network.py

[p-glaum]

Overestimation of line capacity after raising the voltage level to 380V ?

• after running the following code the s_nom values of each converted line is higher than it used to be on the lower voltage level

def simplify_network_to_380(n):
    ## All goes to v_nom == 380
    logger.info("Mapping all network lines onto a single 380kV layer")
    n.buses['v_nom'] = 380.
    linetype_380, = n.lines.loc[n.lines.v_nom == 380., 'type'].unique()
    lines_v_nom_b = n.lines.v_nom != 380.
    n.lines.loc[lines_v_nom_b, 'num_parallel'] *= (n.lines.loc[lines_v_nom_b, 'v_nom'] / 380.)**2
    n.lines.loc[lines_v_nom_b, 'v_nom'] = 380.
    n.lines.loc[lines_v_nom_b, 'type'] = linetype_380
    n.lines.loc[lines_v_nom_b, 's_nom'] = (
        np.sqrt(3) * n.lines['type'].map(n.line_types.i_nom) *
        n.lines.bus0.map(n.buses.v_nom) * n.lines.num_parallel)

• as far as I understand the num_parallel value includes the correction factor which is the squared quotient of original voltage level and the 380kV : (n.lines.loc[lines_v_nom_b, 'v_nom'] / 380.)**2

• however, I do not understand why the quotient is squared

• additionally, I`m wondering where the correction factor for the current increase of the 380kV line type is accounted for. In the n.line_types the i_nom attribute of 380kV lines is 2 times higher than 220kV lines

• this leads to an overall overestimation of the line capacity by a factor of 1.1578 (220/380*2)