Research of DC Current Transformer Based on Optical Fiber Thermometry

In the paper a review on the potential advantages of optical current transformers points out that it is the technology trend on the development of current transformer. But there are many more difficulties to be resolved, innovative ideas of developing optical current transformers must be strengthened. Thin film sensor has the advantages of small size and low cost, which has become a research hotspot in recent years. A measurement system of passive optical fiber DC current sensor based on the thin film sensors is designed in this article. The tested current generates applied voltage by a shunt and transfers into the change of temperature rising after a thin film resistor in the high voltage side. Then the current information is got indirectly by measuring the temperature signal. Designs of electric-heating converter, heating-light converter and low-voltage measurement display system are introduced in detail. Experimental results indicate that the general linear correlation between the time constant of fluorescent lifetime T and the voltage across the thin film resistor. The feasibility of measurement system is verified via the results of the experiment.