CT saturation classifications using correlation technique

This paper presents an algorithm for current transformer (CT) saturation classifications based on correlation technique for bus bar protection. The algorithm calculates 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. The technique classifies the degree of the CT saturation to weak, moderate and severe saturations. The results indicate that the technique is very accurate and useful in selecting the more suitable operating characteristics for differential relays to avoid the false operation.