Study on the characteristics of all fibre optical current sensor linear fitting algorithm

Fiber optic current sensor is based on the Faraday effect of magneto optic materials, in the isotropic optical transparent medium, the magnetic field can make the plane polarized light propagating polarization plane rotated along the magnetic field. Deflection angle is proportional to the magnetic field intensity. It can be used to detect current in a magnetic field. With its high measuring precision, wide measuring range and strong anti-interference ability, Polarized reflectance interference light path structure of optical fiber current sensor is widely and deeply studied now, it has become the most mature fiber current sensing scheme in the current detection. For example, type of FOCS was used for the suspension test.What is important fact that existing optical fiber current sensor not been to promote, the main reason is lack of studying the sensor characteristics. Its reliability is difficult to meet the harsh operating conditions in industrial field. Adopting mathematical optimization method, this paper discusses the end fitting, the average points fitting, least square method, and the optimal linear least absolute deviation method which is applicate the linear characteristics of optical fiber current sensor. Analysis and verify the effect of different algorithms for linear measurement and ideal characteristics. The results show that different linear fitting methods are different results about the sensor. Using the least square method and best linear fitting method (regression line) obtained optical fiber current sensor linearity fitting degree is better, reach ±0.069% and ±0.071% respectively. Therefore, Least squares fitting algorithm and the best line can be widely used in the evaluation of high precision instrument ( 0.1%), We can use the end fitting, mean point fitting, This paper for the research, design, evaluation and use all fiber optic current sensor have great important in intelligent power grid monitoring and protection, energy saving and emission reduction, energy efficiency measurement simultaneously