The performances of the inrush current identification methods are influenced by the winding currents on the delta side of transformer windings. Algorithms based on winding currents can be used to improve the performance of transformer protection. The drawbacks of the present method of calculating the circulating current are discussed. Firstly， a new current transformer configuration is presented， and the relationship between zero sequence current on the star side and the circulating current on the delta side is derived based on the transformer voltage loop equations. The per phase inrush current is fitted with the combination of phase current and zero sequence current. The correlation formula is used to describe the characteristics of the fitted magnetizing currents， and the ratio between zero sequence current and circulating current is determined according to the value of the correlation coefficient. The circulating current can then be obtained. This method does not need the parameters of the windings and is not affected by the different switching phase angles. It can be easily realised in practice. The usefulness and correctness of the presented method are verified by the ATP simulations.