In this paper we propose a method for analyzing the operation health of a large number of all-fiber optical current transformers used in UHV converter stations by studying the correlations of their operating parameters. This method firstly realizes automatic data sampling of operation parameters of all-fiber optical current transformers by building a monitoring network. Then the method calculates the deviations of the operating conditions from their ideal values and the correlations between the relative parameters, thus achieves the operation health condition of the main functional modules in optical current transformers. Finally, through big data analysis, the comprehensive health index and service life of each optical current transformer are predicted. The proposed method can realize the health monitoring of all optical current transformers, which will guarantee their reliable operations and decrease the potential faults.
In this paper, we demonstrate a novel Fano resonance optical filter based on thin fiber taper coupled whispering gallery mode (WGM) liquid core microcapillary resonator, and such the filter comes from the narrow band transmission spectrum of Fano resonance. Due to the large thermos-optical coefficient of the liquid core, slight temperature change will greatly change the resonant wavelength. In addition, high order resonant modes are generated through thin fiber taper coupling. With their large intensity fraction in the liquid core, these modes achieve high sensitivity to refractive index change or temperature change of the liquid core. So this tunable filter has very large temperature tunable coefficient of about 0.4nm/K, which is far larger than other traditional methods.