Research On Multi-parameter Monitoring Method Of Electronic Transformer Based On Optical Fiber Sensing Technology

As one of the key measuring devices in the power system,the transformer is susceptible to external temperature,humidity,pressure,vibration,noise and so on,the electronic transformer measurement accuracy stability and reliability of long-term operation work makes uncertainty.According to the electronic transformer power system operating state monitoring requirements,a variety of parameter measurement methods based on temperature,humidity,air pressure and vibration of fiber grating sensors are studied in this paper,and the monitoring system of electronic transformer operating condition based on LabVIEW is established.At first,according to the real-time monitoring requirement of the electronic transformer,a kind of FBG pressure sensing model based on the patch-type structure is constructed.The integrated monitoring of air pressure and Temperature is achieved.On this basis,a differential FBG pressure sensor with adjustable range and a differential FBG pressure measurement method for dynamic pressure monitoring of airspeed tube are proposed respectively.Secondly,a fiber grating humidity sensor based on polyimide humidity sensitive film is designed to meet the requirements of the humidity monitoring of electronic transformer.The organic PC(polycarbonate)tube packaging method is designed to meet the strong electromagnetic field and high temperature test environment.In addition,the temperature and humidity sensitivity characteristics of the fiber grating humidity sensor without coating layer and coated layer are also given.Thirdly,according to the requirements of vibration monitoring of electronic transformer,a cantilever vibration monitoring system based on the strain-vibration transformation model is built.Based on this,a kind of fiber grating vibration sensor based on arched beam structure is studied.Then,according to the stability of the operation state error and the SF6 gas insulation characteristic,the influence of temperature and other environmental factors on the stability of the operation error in the electronic transformer is studied.An inversion model of SF6 gas with the temperature,pressure and density is established.The calculation method of SF6 gas density and humidity volume fraction are also given.Finally,on-line monitoring hardware system of electronic transformer based on fiber grating sensor is designed for the demand of transformer comprehensive running condition monitoring.This system achieved the function of temperature,humidity,pressure,vibration and other parameters monitoring,as well as the displaying and warning by means of the monitoring software of LabVIEW.