How Do Fiber Optic Current Sensors Work in Substations?

Click For Summary

Homework Help Overview

The discussion revolves around fiber optic current sensors (FOCS) used in substations, specifically focusing on two configurations: the Sagnac interferometer configuration and the reflective configuration. The original poster seeks detailed explanations of these configurations, including their principles of operation, differences, and performance characteristics.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the underlying principles of the FOCS configurations, particularly the Faraday effect and phase shifts. The original poster requests further clarification on the configurations and their operational details, as well as sources for additional reading.

Discussion Status

Some participants have provided initial insights into the configurations and suggested resources for further study. The original poster acknowledges the need for more information and expresses gratitude for the responses received. However, the discussion appears to lack a comprehensive resolution, as further questions remain regarding the effects of temperature on these sensors.

Contextual Notes

The original poster is an undergraduate student conducting research and is under time constraints, seeking information quickly. There is an indication of a need for deeper understanding of the technical aspects involved in fiber optic current sensing.

strafer
Messages
3
Reaction score
0
Hello..I'm a undergrad student from hyderabad ,India. Presently I'm 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'm 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

http://www.mediafire.com/?yjotjb1tim2cv4m (link to pdf)
 
Last edited by a moderator:
Physics news on Phys.org
You are asking for a great deal here!

I will only summarize: both configurations depend on the Faraday effect, which basically states that there is a nonreciprocal phase shift induced between the counterpropagating beams. The light must be circularly polarized, as I recall (not sure anymore about this). Since a current develops a static or quasi-static magnetic field, this phase shift is a measure of the current's intensity. You will need to do a good deal of reading on how this phase shift iselectronically processed (the path lengths are ac-modulated and phase-sensitively demodulated, etc.)

In the "Sagnac" configuration (and BTW the Sagnac effect itself is a source of error here), light is launched into both fiber coil ends, then ther two emerging beams are allowed to interfere with another to determine the phase shift. In the case of the reflectng configuration, resonance is set up in a closed fiber optic coil, but again the phase shift indicates the magnitude of the current.
 
I went thru the paper again ..even i analyzed that i had asked for more sorry for that..
and btw you said that i have to do a lot of reading on how phase shift is electronically processed..so can you tell me the source of that info... please suggest ..any book or online

btw thank you for the above info!
 
Last edited by a moderator:
The classic is a book by the German publisher Springer-Verlag (it's in English). It contains many of the early and best papers on the subject, by many authors. But I warn you, it's expensive. UIt may be out of print by now. And it does not address current sensing.

Also very good is the book by Herve LeFevre: http://books.google.com/books/about/The_fiber_optic_gyroscope.html?id=5W9TAAAAMAAJ

I found this on the Web, looks excellent, is encompassing, and incredibly it's free: http://www.uta.edu/rfmems/Teralum_old/00902150.pdf

Beyond that I suggest you also do some googling.
 
thank you for the info..btw can you tell me how temperature affects this type of optical sensor??
 
Last edited by a moderator:
Rude man has given you a starting point. You need to do your own research now.

Thread locked.
 

Similar threads

Dark fiber optic cables as Earthquake detectors
  • · Replies 9 ·
Replies
9
Views
2K