How Do Fiber Optic Current Sensors Work in Substations?

[strafer]

Hello seniors..im a undergrad student from hyderabad ,India. Presently I am am doing a theory based research project on fiber optic current sensors ..which are mainly used to sense current in substations .

Recently i got a paper when i googled on the net. It was titled Temperature and Vibration Insensitive Fiber-Optic current sensor(pdf file attached ). In this papers two configurations of FOCS are discussed

-fiber-optic current sensor with 1.Sagnac interferometer configuration
2 .Reflective configuration

As I am still graduating ..i don't have a deep knowledge on these configs but howevr I am aware of the basics of fiber optics and communications

Can anyone explain the following :

1.these two configs in detail...also differences between them ,pricniples of operation,current ratings measured by each..advantages and disadvantages etc

2.paper explanation in detail..

Hoping for positive replies...please help i need this info ASAP

 

[gtoguy97]

Thank you in advance 1. The Sagnac interferometer configuration of the Fiber-Optic Current Sensor (FOCS) is a passive configuration that relies on the Sagnac effect to convert the AC current waveform to a DC voltage signal. When an AC current passes through the sensor coil, the magnetic field generated by the current causes a refractive index gradient within the fiber which results in an interference pattern between the two counter-propagating light waves. This interference pattern is then converted to a DC voltage signal which can be read by a monitoring system. The reflective configuration of the FOCS is a more active configuration that utilizes an optical circulator. In this configuration, an optical circulator is used to separate the two counter-propagating light waves and to reflect them back into the sensor head. The change in the refractive index caused by the AC current is then detected as a phase shift between the two waves which can be read by a monitoring system. Both configurations are able to measure AC currents up to hundreds of Amps, depending on the size and type of the sensor head. In terms of advantages and disadvantages, the Sagnac interferometer configuration is simpler and cheaper to implement but has lower sensitivity compared to the reflective configuration. The reflective configuration is more expensive to implement but provides better sensitivity and dynamic range. 2. The paper explains the design and performance of two different configurations of the Fiber-Optic Current Sensor (FOCS) for sensing AC currents. The paper first discusses the design of the Sagnac interferometer configuration and its performance in terms of sensitivity, dynamic range, and noise. It then covers the design of the reflective configuration and its performance in terms of sensitivity, dynamic range, and noise. The paper also includes results from experiments which compare the performance of both configurations. Finally, the paper concludes with recommendations for future work and applications.