def lv_line_load(network):
    """
    Checks for over-loading issues in LV grids.

    Parameters
    ----------
    network : :class:`~.grid.network.Network`

    Returns
    -------
    :pandas:`pandas.DataFrame<dataframe>`
        Dataframe containing over-loaded LV lines, their maximum relative
        over-loading and the corresponding time step.
        Index of the dataframe are the over-loaded lines of type
        :class:`~.grid.components.Line`. Columns are 'max_rel_overload'
        containing the maximum relative over-loading as float and 'time_index'
        containing the corresponding time step the over-loading occured in as
        :pandas:`pandas.Timestamp<timestamp>`.

    Notes
    -----
    Line over-load is determined based on allowed load factors for feed-in and
    load cases that are defined in the config file 'config_grid_expansion' in
    section 'grid_expansion_load_factors'.

    """

    crit_lines = pd.DataFrame()

    for lv_grid in network.mv_grid.lv_grids:
        crit_lines = _line_load(network, lv_grid, crit_lines)

    if not crit_lines.empty:
        logger.debug('==> {} line(s) in LV grids has/have load issues.'.format(
            crit_lines.shape[0]))
    else:
        logger.debug('==> No line load issues in LV grids.')

    return crit_lines
Checks for over-loading issues in LV grids.

    Parameters
    ----------
    network : :class:`~.grid.network.Network`

    Returns
    -------
    :pandas:`pandas.DataFrame<dataframe>`
        Dataframe containing over-loaded LV lines, their maximum relative
        over-loading and the corresponding time step.
        Index of the dataframe are the over-loaded lines of type
        :class:`~.grid.components.Line`. Columns are 'max_rel_overload'
        containing the maximum relative over-loading as float and 'time_index'
        containing the corresponding time step the over-loading occured in as
        :pandas:`pandas.Timestamp<timestamp>`.

    Notes
    -----
    Line over-load is determined based on allowed load factors for feed-in and
    load cases that are defined in the config file 'config_grid_expansion' in
    section 'grid_expansion_load_factors'.