Photothermal Radiation Measurement Of Aging Characteristics Of Silicone Rubber Composite Insulators

Silicone rubber composite insulators not only have excellent hydrophobicity,but also have high mechanical strength and light weight,and are widely used in power systems.The aging phenomenon of composite insulators is inevitable during operation,which reduces the performance of composite insulators.Monitoring the aging status of composite insulators and replacing unqualified composite insulators in time will help to improve the stability of power system operation.Based on the photothermal radiation technology,this studies proposes a theoretical optimization model of photothermal radiation for composite insulators,improves the reliability of measurement data,and studies the changes of thermal physical properties of composite insulators after aging.The main research contents are as follows:First of all,a complete theoretical model of photothermal radiation is established,and simulation analysis is carried out to study the influence of various physical parameters on the infrared radiation signal.The research shows that the influence of the two absorption coefficients cannot be ignored when establishing the theoretical model of photothermal radiation based on composite insulators,which poses a challenge to the inversion of thermophysical parameters.Secondly,the theoretical model of equivalent photothermal radiation for composite insulators is optimized,and a method of absorbing and surface treatment is proposed,which reduces the number of parameters to be fitted and simplifies the theoretical formula.Based on the optimized theoretical model of photothermal radiation,the physical parameters affecting the infrared radiation signal were simulated and analyzed,including the physical parameters of the metal layer,the physical parameters of the aging layer,the interface thermal resistance,and the excitation light spot radius.Requirements for the thermal diffusivity and thickness of the metal layer and the excitation light spot radius during the experiment were proposed.Finally,the aging characteristics of composite insulators with different aging degrees were measured.The research shows that the aging process of composite insulators is a process from the outside to the inside,and the surface aging degree is not constant,but continues to decline.The uniqueness of the fitting result is analyzed,and it is proved that the best fitting result is unique,and the measurement result is true and effective.To sum up,this studies carries out the optimization of the photothermal radiation model based on composite insulators,proposes the method of absorbing surface,improves the reliability of parameters,and is an effective means to measure the aging characteristics of composite insulators.