Fiber Bragg Grating DC Current Sensor

Power system is the basis for national economic development, it has a significant place in national economic construction. With the rapid development of economic, the demand for electricity in various countries are increasing, resulting in power system rated voltage and current level year by year. The measurement of current and voltage has a very important role in power industry, they provide the power system necessary informations for measurement, control and relay protection and so on. Optical fiber current sensor has obvious advantages, is a ideal alternate for the traditional oil-filled electromagnetic induction current transformer. The optical fiber current sensor almost overcomes all the shortcomings of the traditional current transformer in the theory. In this paper, the fiber Bragg grating with equal intensity beams combination is the sensitive components of the large direct current sensor. With such intensity Beams can avoid the interference of vibration measurement on-site to reduce the error.At present the research of fiber grating current sensor focus on the structure such as main strength of cantilever and the magnetostrictive material type, cantilever can not overcome the interference, currently remain in the experimental stage, The sensing probe made of FBG magnetostrictive materials,the thermal effect of magnetostrictive material itself can also cause the value of the grating reflection wavelength drift.The sensor structure of this paper overcomes the vibration interference, but also for the temperature compensation, without measuring the impact of changes in ambient temperature. This reality, studied the fiber Bragg grating modulation and demodulation techniques, taking into account the field measurement environment, designed two programs grating structure of DC-current sensor. Two programs'sensing probe sensors are made up of fiber Bragg grating with equal intensity beams combined, during the simulation and field experiment to verify the feasibility.Major research work includes the following sections:(1) Analysis of fiber Bragg grating based theory of the optical fiber grating strain and temperature characteristics of this fiber grating demodulator used in a certain way of doing research.(2)We designed two different structures of simply supported beam after researched the strain characteristics of beams. (3) For this article, the two proposed structures of large current sensing FBG sensor were studied.This article is a very good attempt of studying the large current FBG sensors, provided a reference for the fiber grating sensing technology into the high current measurement.