Error Suppression Of Optical Fiber Voltage Sensor Based On Photonic Crystal Fiber

Optical Voltage Sensor(OVS)is a new type of power system detection device which has been studied in various countries in the world,and it could replace the traditional oil-immersed transformer and has a good research prospect,and the error problem caused by temperature disturbance has always been the main reason restricting its development.Photonic Crystal Fiber(PCF)is a new special fiber,with periodic air hole so the fiber structure parameters can be flexibly designed,the temperature stability is better than the traditional single-mode fiber,can be used as a sensing fiber to improve the temperature stability of optical fiber sensing system to suppress temperature error,inhibits the influence of temperature disturbance and improves the measurement accuracy.This thesis takes OVS based on inverse piezoelectric effect as the research object,optical fiber as an important part of OVS,using the excellent characteristics of PCF,the design of PCF with temperature stability as OVS sensing fiber,reduce the error caused by sensor fiber under the action of temperature,so as to realize the suppression of OVS temperature error.The main works of this thesis are as follow: The output model of OVS is analyzed and deduced by analyzing the working principle of OVS.This thesis analyzes the main error sources of OVS,and proposes to use PCF as a new type of sensing fiber to suppress the temperature error of OVS.The numerical analysis methods commonly used in PCF are introduced,and the temperature stability of PCF under temperature action is analyzed by finite element method.Aiming at the main error source sensing fiber in OVS,this thesis analyzes the error of sensor head sensing fiber and the error caused by the unequal length of two-stage optical fiber in the scheme,and deduces the corresponding error formula,and analyzes the thermal error of sensing fiber,and gets the corresponding error model.This thesis introduces the design idea of the special optical fiber,analyzes its feasibility,and designs a pentagonal structure of the PCF.The temperature stability of the proposed temperature insensitive PCF is analyzed,considering the influence of thermal light effect and thermal expansion effect,and the change of fiber performance after the change of air hole diameter,air pore layer and air hole spacing under the action of temperature is analyzed.The model field characteristics of the designed fiber and the reference fiber designed by the traditional panda type PCF are compared and analyzed.Finally,the temperature stability of the designed temperature insensitive fiber is calculated,the error formula is introduced and the inhibition effect of the optical fiber on the system error is analyzed.After studying this topic,the following conclusions are drawn,the stability of optical fiber as a key link of OVS can affect the output error of OVS,and the temperature stability of the designed five-core PCF is stronger than that of the reference six-core PCF by analyzing the PCF of the design.The Mold field area of the PCF is larger than six cores PCF,and the distribution of the mold field is close to the circle,which has advantages when the actual mode field is matched,and the error formula is analyzed,and it is found that using the fiber as a sensing fiber can improve the temperature stability of the system,reduce the measurement error,it can inhibit the error caused by the external ambient temperature disturbance to the OVS.The research of this subject will provide a reliable theoretical basis for solving the bottleneck problem of temperature error of OVS under the action of temperature,and provide new research ideas and methods for promoting the development of OVS.