This paper analyzes the response of optical fiber current sensors that are subjected to high electric fields, such as fields encountered in gas-insulated systems. This paper shows that through the electrooptic (EO) Kerr effect, these fields can cause harmonic distortion of the measured ac current waveform. This harmonic distortion was confirmed experimentally. Also, this paper shows that it is possible to simultaneously measure both current and voltage waveforms and the phase between them using this effect. To minimize the electrooptic Kerr effect, optical fiber current sensors must be screened from high-electric fields.
Allen H. Rose, S. M. Etzel, and Kent B. Rochford, "Optical Fiber Current Sensors in High Electric Field Environments," J. Lightwave Technol. 17, 1042- (1999)