The integrator of a Rogowski coil current transformer will amplify the error of current transfer and probably cause serious distortion of the current transfer. This will lead to protection mal-operation. To this end, an improved idea for a line relay directly using the differential current output of Rogowski coil is put forward. Taking the differential relay as an example, a current differential relay of the transmission line based on an active electronic transformer using value after equal transfer processes is proposed. In the scheme, the differential current output from the Rogowski coil is directly used for protection calculation, and the voltage signal used for capacitance current compensation calculation is transformed by a virtual Rogowski coil to ensure that the voltage and current signals have the same transfer process. Simulation and experimental results demonstrate that the novel relay has high operational speed in the case of internal faults, the influence of the transmission error introduced by the integral link is eliminated, the impacts of voltage and current signal transmission difference on protection accuracy are mitigated and the performance is superior to the existing differential protection methods. This work is supported by the National Natural Science Foundation of China (No. 51877090).