This paper explores the possibility of improving the protection of power systems by the application of Rogowski coils in place of current transformers. The comparison was made between the features of the Rogowski coil against that of a current transformer, with an emphasis on how this impacts on the operation of relay protection. A detailed analysis was carried out into the conditions that existed in the current transformer and its behavior in relationship to the increase in primary current with emphasis during transients in the network. By simulating different operating conditions it seeks to qualitatively demonstrate the impact of various factors which, result in the saturation of the magnetic core of a current transformer, together with the associated secondary current distortion and accuracy. It also describes the basic features of numerical relays, the factors affecting distortion of the input current shape and the impact of this on the operation of relay protection. Furthermore, it describes the principles of the operation of a Rogowski coil. The problems associated with the measurement of small currents, together with the characteristics and performance of the Rogowski coils and their interface with the relay. In the penultimate chapter a comparison is made between the features of the current transformer and the Rogowski coil current sensor, with emphasis on the impact of these features on relay protection. The paper concludes with a description of how the Rogowski coil can be integrated into a power system and the opportunity it presents to improve relay protection, in comparison to that of a conventional current transformer. It describes the results of a trial which was carried out in which a Rogowski coil was integrated into an existing power system. Tests were conducted to simulate multiple failures for which current measurements were made and for which the operation of the relay was monitored.