This paper presents an advanced technique for avoiding current transformer saturation effects on busbar protection.  The technique classifies the CT saturation into degrees depending on calculating the correlation coefficient between the saturated secondary current of the faulted circuit and the summation of the other secondary currents for the un-faulted circuits. This estimation is performed for external faults. The technique is useful in adapting the differential relay characteristics of the protected busbar to avoid false operation. The proposed technique has attractive features include the simplicity for on line implementation, not affected by the remanent flux in the CT core, and it is independent of the CT parameters/characteristics of secondary burden. The accuracy and robustness of the introduced algorithm are demonstrated through extensive simulation cases reflecting a wide range of variation in fault conditions and CT parameters.