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A Fiber-Optic Current Sensor for Lightning Measurement ApplicationsAn optical-fiber sensor based on Faraday Effect is developed for measuring total lightning electric current. It has many unique capabilities not possible with traditional current sensors. Designed for aircraft installation, the sensor is lightweight, non-conducting, structure-conforming, and is immune to electromagnetic interference, hysteresis and saturation. It can also be used on windmills, lightning towers, and can help validate lightning detection network measurements. Faraday Effect causes light polarization to rotate when the fiber is exposed to a magnetic field in the direction of light propagation. Thus, the magnetic field strength can be determined from the light polarization change. By forming closed fiber loops and applying Ampere's law, measuring the total light rotation yields the total current enclosed. The broadband, dual-detector, reflective polarimetric scheme allows measurement of both DC component and AC waveforms with about 60 dB dynamic range. Three sensor systems were built with different sensitivities from different laser wavelengths. Operating at 850nm, the first system uses twisted single-mode fiber and has a 150 A - 150 KA range. The second system operates at 1550nm, uses spun polarization maintaining fiber, and can measure 400 A - 400 KA. Both systems were validated with rocket-triggered lightning measurements and achieved excellent results when compared to a resistive shunt. The third system operates at 1310nm, uses spun polarization maintaining fiber, and can measure approximately 300 A - 300 KA. High current measurements up to 200 KA were demonstrated at a commercial lightning test facility. The system was recently installed on an aircraft and flown near icing weather conditions.
Document ID
20150010964
Acquisition Source
Langley Research Center
Document Type
Conference Paper
Authors
Nguyen, Truong X. (NASA Langley Research Center Hampton, VA, United States)
Ely, Jay J. (NASA Langley Research Center Hampton, VA, United States)
Szatkowski, George N. (NASA Langley Research Center Hampton, VA, United States)
Date Acquired
June 17, 2015
Publication Date
April 20, 2015
Subject Category
Air Transportation And Safety
Avionics And Aircraft Instrumentation
Report/Patent Number
NF1676L-19939
Meeting Information
Meeting: SPIE DSS Sensing Technology + Applications- Multisensor, Multisource Information Fusion: Architectures, Algorithms, and Applications 2015
Location: Baltimore, MD
Country: United States
Start Date: April 20, 2015
End Date: April 24, 2015
Sponsors: International Society for Optical Engineering
Funding Number(s)
WBS: WBS 648987.02.01.07.20
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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