Preliminary evaluation of optically-interrogated Rogowski coils: Compliance with power system protection classes

In this paper we report on recent investigations into the performance of an optically-interrogated Rogowski coil designed for power system protection applications. Preliminary evaluation of the pre-prototype device shows that the amplitude and phase errors at its rated current of 1 kA and at rated frequency are around 0.1 % and 0.1° respectively. Based on the experimental results it can be concluded that the proposed approach of Rogowski coils monitored passively by distributed optical sensors has the potential to ensure conformance with the 5P protection and 0.5 standard classes specified by IEC 60044-8, while introducing a host of benefits that result from the passive and dielectric nature of the interrogation technique.