Design,Implementation And Property Of Rotary Optical Electric Field Sensor

In recent years,voltage and capacity of the electric power system have been improved in a great extent with the rapid development of electric power industry,the applications for electric field measurements are more extensive either.Optical electric field sensors can overcome the intrinsic defects of conventional sensors owing to advantages such as light weight,fast dynamic response,wide bandwidth,high insulation,and etc,thus have bright prospects.However,the sensors have not been widely used because of temperature instability and problems existing in measurement for DC field and electric field at extremely low frequency(ELF).The paper proposes a new design of sensors based on Pockels effect to solve problems for ELF and DC measurements,which is called rotary optical electric field sensor.Firstly,the mathematical model of Pockels effect of a BGO crystal in rotary optical electric field sensor is built to study the relation between phase retardation and frequency of the sensor.Then combining Jones calculus method of polarization system,the output of the whole sensing unit is deduced to explain the operational principle in essence and provide theoretical basis for its design and implementation.Secondly,the finite element model of Pockels effect in a BGO crystal and model of the whole sensing unit of rotary optical electric field sensor are established respectively.Using the software Comsol,the relationship between phase retardation and rotating angle is analyzed,and different changes of output intensity with rotating speed is considered.Then,the mechanical configuration of the proposed sensor is designed including sensing head,driving section,and rotating optical path.The drawing is finished in the Solidworks software and finally turned into a production.Thirdly,the extended Kalman filtering algorithm with frequency tracking function is introduced into the signal processing system of the rotary optical electric field sensor.An experimental platform is established to test and evaluate its performance.The results show that the proposed sensor has a good linearity and can be applied to the measurement of electric field.Finally,the influences to accuracy and stability of the sensor are deduced and simulated from the aspects such as optical path system(including light source,collimator,fiber optic rotary joint,polarizer,analyzer,quarter-wave plate and BGO crystal),circuit system,electric field distribution,mechanical structure of sensing head,vibration and etc.The corresponding compensation measures are put forward.