def ult_top_oil_rise_at_load(K, R, dTOr, x):
    """ Calculate the steady-state top oil rise for a given load
    K = Ratio of ultimate load to rated load
    R = Ratio of load lossed at rated load to no-load loss
    on top tap being studied
    x = oil exponent based on cooling method
    TOrated = Top-oil temperature at rated load (as determined by heat run)
    """
    dTO = dTOr * ((((K**2) * R) + 1) / (R + 1)) ** x

    return dTO