An Improved Fast Distance Relay to Mitigate the Impacts of Rogowski Coil Transducer Transient

The Rogowski coil transducer's integrator will amplify the transmission error, which may lead to mal-operation of the relay. In this paper, a novel method of line relay based on the differential output of Rogowski coil is proposed. Besides, an improved fast distance relay based on the differential output of Rogowski coil is presented. Based on the equal transfer process of transmission lines(ETPTL), the voltage signal should be processed by the virtual Rogowski coil to solve the inconsistent transfer problem between voltage and current. Furthermore, this paper also presents the reconstruction method of voltage at the fault point and the least-square algorithm to solve the R-L differential equation, so as to improve the algorithm accuracy. Furthermore, the equal transfer process error of the virtual Rogowski coil is analyzed in the paper, and the design principle of low pass filter is also proposed. Simulation results and experiment results demonstrate that the improved fast distance relay scheme has high operation speed, which is signed prior to other distance relay schemes. The proposed method also provides a valuable reference for other types of transmission line relay based on Rogowski coil transducer.