def voltage_delta_vde(v_nom, s_max, r, x, cos_phi):
    """
    Estimate voltrage drop/increase

    The VDE [#]_ proposes a simplified method to estimate voltage drop or
    increase in radial grids.

    Parameters
    ----------
    v_nom : int
        Nominal voltage
    s_max : float
        Apparent power
    r : float
        Short-circuit resistance from node to HV/MV substation (in ohm)
    x : float
        Short-circuit reactance from node to HV/MV substation (in ohm). Must
        be a signed number indicating (+) inductive reactive consumer (load
        case) or (-) inductive reactive supplier (generation case)
    cos_phi : float

    Returns
    -------
    :any:`float`
        Voltage drop or increase
        
    References
    ----------
    .. [#] VDE Anwenderrichtlinie: Erzeugungsanlagen am Niederspannungsnetz –
        Technische Mindestanforderungen für Anschluss und Parallelbetrieb von
        Erzeugungsanlagen am Niederspannungsnetz, 2011

    """
    delta_v = (s_max * (
        r * cos_phi + x * math.sin(math.acos(cos_phi)))) / v_nom ** 2
    return delta_v
def voltage_delta_vde ( v_nom , s_max , r , x , cos_phi ) : delta_v = ( s_max * ( r * cos_phi + x * math . sin ( math . acos ( cos_phi ) ) ) ) / v_nom ** 2 return delta_v
Estimate voltrage drop/increase

    The VDE [#]_ proposes a simplified method to estimate voltage drop or
    increase in radial grids.

    Parameters
    ----------
    v_nom : int
        Nominal voltage
    s_max : float
        Apparent power
    r : float
        Short-circuit resistance from node to HV/MV substation (in ohm)
    x : float
        Short-circuit reactance from node to HV/MV substation (in ohm). Must
        be a signed number indicating (+) inductive reactive consumer (load
        case) or (-) inductive reactive supplier (generation case)
    cos_phi : float

    Returns
    -------
    :any:`float`
        Voltage drop or increase
        
    References
    ----------
    .. [#] VDE Anwenderrichtlinie: Erzeugungsanlagen am Niederspannungsnetz –
        Technische Mindestanforderungen für Anschluss und Parallelbetrieb von
        Erzeugungsanlagen am Niederspannungsnetz, 2011