| Compared to traditional current transformer, Optical current transformer (OCT) has strong anti-electromagnetic interference ability, wide dynamic range, simple insulated structure and easily connected to computer, so, there are broad development prospects in electric power systems. The OCT of Faraday principle of magneto-optical effect has the potential of becoming the ideal current transformer, but it still face considerable practical use of challenge-the influence of multiple parameters caused by temperature resulting in inaccurate measurements.The OCT introduces FBG temperature sensor as its auxiliary devices for more OCT measurement accurate and eliminating the effects of temperature. There are strong electromagnetic interference resistance, high stability and accuracy which can get to0.1℃, simple structure, distributed widely, mature writing technology, easily commercialization etc, so the FBG was applied successfully in the field of Electric power system as a temperature monitor of the switching unit and the power cable. Composite sensor compensation systems was presented and designed as a new kind of optical current transducer sensor compensation system.Sensing head part of the system are composed of small dimension YIG and FBG, it has the ability to measure the circuit current accurately through temperature compensation for optical current transformer.This paper completed the design, data fusion algorithm and experiment research of the optical current transformer compensation system. It adopts LD as signal light, PIN tube for photoelectric detector, capture card for data acquisition of current signal, the LabVIEW virtual instruments for various algorithms such as filtering the original signal processing, demodulation of FBG temperature sensor by demodulation instrument, and realizes temperature compensation finally by merging current and temperature in computer. Experiment results show that this system has the feasibility and measurement errors reduced by an order of magnitude. |
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