| There is a wide demand for high voltage DC power in many industrial,military and civil applications.The traditional direct current high voltage measurement methods such as high-resistance voltage divider and electrostatic voltmeter have the disadvantages of low accuracy,low reliability and complicated operation.It cannot meet the requirements for measurement accuracy and response speed.In view of this,this project intends to study a new optical voltage sensing technology with a voltage level of 6k V,small size,light weight,convenient use,high accuracy and response speed for high voltage direct current voltage measurement.It provides a new idea and a new method for solving the application of high voltage direct current measurement technology in industry and military field.The main work is as follows.Firstly,the inverse piezoelectric effect response characteristics of piezoelectric ceramics and the sensing characteristics of fiber gratings are theoretically clarified,and the basic model of the sensing unit is constructed;The reference grating method is used to solve the cross-sensitivity of grating temperature and strain,this thesis describes the basic principle and scheme design of direct current voltage sensing technology based on fiber bragg grating.Secondly,this thesis compares and analyzes the influence of different piezoelectric ceramic materials,structural dimensions and pressure methods on the sensitivity,and optimizes the experimental plan.Based on the coupled mode theory,the spectral characteristics of fiber bragg grating are simulated and analyzed,and experiments are designed to study the effects of applying axial prestress and stripping the coating on the sensing characteristics of the fiber grating.In order to avoid the loss of piezoelectric displacement,a sensing unit package structure is designed,and the actual use effect of the structure is verified.Then,apply a low DC voltage to the sensor for testing of basic sensing characteristics.A temperature characteristic detection scheme is designed and the feasibility and specific effects of the reference grating temperature compensation method are analyzed.Finally,the sensing performance and measurement performance of the sensors are further investigated in a high voltage environment,and analyze its repeatability,stability and error.The research results show that the sensor designed in this thesis has good linearity and repeatability.It can realize fast and accurate measurement of direct current high voltage. |
