Application Of Fiber Bragg Grating In Dry Resistance Temperature And Structure Monitoring

In order to protect the security and stability of power system operation,the Power Grid Corp attaches great importance to the development and application of on-line monitoring technology.In recent years,increasing application of 35kV Parallel dry type air-core reactor in power system which runs frequent accidents,and has brought many issues to the security and stability of the power system.Dry type air-core reactor is an epoxy resin and glass fiber reinforced multi-encapsulated parallel structure,which is working in a high voltage,strong magnetic field,high current extreme environment. Operation temperature and electrical power caused the interaction force between high temperature and thermal strain and structural stress is very complex.With the growth of the running time,high temperature and structure stress will enable dry type air-core reactor insulation performance degradation,structure deformation is generated,even burning.The current online monitoring system is mainly for electrical parameters of power equipment monitoring,ignoring the monitoring of non electric parameters.According to the structural characteristics and monitoring requirements of dry typ e air-core reactor, fiber Bragg grating (FBG) sensing technology can achieve non ele ctric parameters online monitoring for dry type air-core reactor temperature and struct ure.The main contents of this paper include:(1) According to the special requirements of temperature and structure monitoring,theoretical analysis and research on the dry type air-core reactor body structure and environmental monitoring.Evaluated the advantages and feasibility of fiber grating sensing technology for dry type air-core reactor temperature and strain monitoring.Combined with process structure and operational failure to analyze temperature distribution and stress distribution of dry type air-core reactor operation state.(2)Starting at the fiber grating sensing mechanism,analyzes the study of the sensing structure model and principle of buried FBG temperature sensor for the structure and monitoring characteristics of dry type air-core reactor,.Complete sensor’s calibration testing and selection process.Test results show that the sensitivity of FBG temperature sensor is 0.01082nm/℃ and the sensitivity of FBG strain sensor is 0.001201nm/με when the initial wavelength is 1550nm.(3)To formulate the sensor installation program by analysis and field experiments with the winding process of dry type air-core reactor,and to complete the development of dry hollow reactor based on fiber Bragg grating.Encapsulation 1,3,6,7,9 only install temperature sensor,5 and 11 encapsulation install temperature sensor and strain sensors.(4)By FBG sensing network for online monitoring of temperature and curing the two processes.Monitoring results show that after the curing temperature stabilized, encapsulation 1,3,5,6,7,9,11 temperatures were 106.41℃,107.36℃,110.13℃, 112.2℃,115.32℃,117.4℃ and 123.19℃,when encapsulation cooled to room temperature,axial and radial strain are the same about -5500με.After the temperature rise stabilized,encapsulation 1,3,5,6,7,9,11 temperature were 81.9℃,93.43℃,95.85℃, 100℃,97.52℃,95.68℃,71.9℃ encapsulation 5 axial strain is about -3200με,and radial strain about -4100με.According to the temperature field,material shrinkage and expansion and effect of electric power to analyze dry-type air core reactor in the curing process and the process of temperature rise test temperature and strain change trend,provide the basis for curing quality and operational safety of the dry type air-core reactor.This paper through theoretical analysis and experiments,carried out a study of the application of fiber grating in the dry type air-core reactor temperature and structure monitoring.In the implementation process, we have completed the development of sensors, on-site construction and monitoring experiments, and these work experience has important reference value to substation dry air-core reactor to achieve a fiber grating non-electrical content monitoring achieve the amount of non-electrical fiber grating online monitoring.