def scMVA(Zth=None, Isc=None, Vth=1):
    """
    Simple Short-Circuit MVA Calculator
    
    Function defines a method of interpretively
    calculating the short-circuit MVA value
    given two of the three arguments. The formulas
    are all based around the following:
    
    .. math:: MVA_{sc} = V_{th}*I_{sc}
    
    .. math:: V_{th} = I_{sc}*Z_{th}
    
    Parameters
    ----------
    Zth:        float
                The Thevenin-Equivalent-Impedance
    Isc:        float, optional
                Short-Circuit-Current, if left as
                None, will force function to use
                default setting for Vth.
                default=None
    Vth:        float, optional
                The Thevenin-Equivalent-Voltage,
                defaults to a 1-per-unit value.
                default=1
    
    Returns
    -------
    MVA:        float
                Short-Circuit MVA, not described
                as three-phase or otherwise, such
                determination is dependent upon
                inputs.
    """
    if not any((Zth, Isc)):
        raise ValueError('Either Zth or Isc must be specified.')
    if Zth is not None:
        Zth = abs(Zth)
    if Isc is not None:
        Isc = abs(Isc)
    if Vth != 1:
        Vth = abs(Vth)
    if all((Zth, Isc)):
        MVA = Isc ** 2 * Zth
    elif all((Zth, Vth)):
        MVA = Vth ** 2 / Zth
    else:
        MVA = Vth * Isc
    return MVA
