Frequency characterisation of an optically-interrogated Rogowski coil for smart grid protection applications

A preliminary frequency characterization of an optically-interrogated Rogowski coil designed for smart grid protection applications is presented in this paper. The investigation into the sensor performance carried out according to the requirements of the 5P protection class specified by the IEC 60044-8 standard revealed that the maximum permissible error is breached at the 4th harmonic for the prototype device. It is demonstrated through numerical simulations that by amending a number of parameters, such as the piezoelectric stack capacitance or the Rogowski coil resistance, the sensor performance can be improved and the class requirements readily satisfied. A refined design of the device is proposed accordingly.