The Research Of Fiber Optic Current Sensor

The current transformer is a very important part in the power system, it is mainly used in the electric energy measurement and relay protection, the sensitivity and reliability of the power system is very important. With the development of power industry, the traditional current measurement device has been unable to meet the modern electric power system, due to its fatal shortcomings. It is bound to seek a suitable alternative to meet the need of reality. In recent years, fiber optic technologybased research and the preparation of new fiber optic sensors, because of its good resistance to electromagnetic interference, small size, light weight, signal transmission fast, stable structure, high sensitivity, has been the focus of research and researchers widespread concern in the market. The current sensor, combined with the magnetic light material as the sensing element, can achieve the linear detection current value, the current detection can be applied to power system under high pressure. So, by relying on the optical fiber sensing technology in the current measurement of the electric power industry will become the development trend of current measurement in the future.In this paper, by consulting a great deal of literature, reviewing the current situation of optical fiber current sensor development at home and abroad, analyzing the advantages and disadvantages of various kinds of fiber optic current sensor and technical problems at present, combined with the basic principle of Fiber Bragg Grating, we put forward a new kind of optical fiber current sensor design method.First of all, we put forward a new optical fiber current sensor, which lays FabryPerot cavity, the spring force and the electromagnetic induction law as the foundation, the two port optical fiber are arranged and fixed on the two electrical wire, magnetic field generated by the current deformation, under the action of the spring, which resulted in changes the cavity length of the Fabry-Perot cavity, finally through theanalysis of the spectral changes of incident light optical fiber measurement, so we can realize the size and change of current. Experimental results show that the sensitivity of the sensor is 10 nm/A, and the response time is faster. Therefore, the structure can get good use in high-current devicesSecondly, we propose a kind of design method, which combined fiber bragg grating fiber with magnetostrictive materials for current measurement. The sensor can take advantage of magnetostrictive material dimensional change in the magnetic field, and cause axial strain coated fiber grating. In the end, the Prague center wavelength drift, thus indirectly measure the size of the current to be measuredIn this paper, the two kinds of design schemes are proposed, it can realize the measurement of the DC current, provide a new way or method for fiber optic current sensor.