基于电致发光效应的输电线路零值绝缘子自诊断关键技术OA

To address the challenges of inadequate detection accuracy in the live-line identification of zero-value insulators on transmission lines,this study investigates the luminescence mechanisms of electroluminescent materials.This is achieved through experimental analysis of various factors that influence the photoluminescent characteristics of ZnS:Cu.An electroluminescent coating spray was developed for application on porcelain insulator surfaces,and its critical luminescence threshold electric field was determined.Finite element simulations were conducted to calculate the electric field distribution across the surfaces of porcelain insulators,and in conjunction with the coating's critical threshold,optimal application locations and coating area dimensions were identified.Finally,a self-diagnosis scheme for transmission line zero-value insulators was proposed based on electric field simulations and live-line test results under various operational conditions.Research results indicate: Firstly,the effects of external factors and the internal filler ratio on the luminescence characteristics of ZnS:Cu electroluminescent coatings were examined through both theoretical analysis and experimental methods.Electroluminescent coatings suitable for application on the surfaces of insulators were developed.The luminous brightness of the electroluminescent coating initially increases and then decreases with the rise in coating thickness,filler concentration,and the mass fraction of high dielectric constant particles.Furthermore,the critical luminescence threshold electric field of the controlled electroluminescent coating can be maintained at approximately 200 kV/m.Compared to the electroluminescent coating before modification,the critical luminescence threshold electric field of the modified coating was reduced by approximately 83.33%,effectively lowering the threshold required to initiate electroluminescence. Secondly,the results of the electric field simulation indicate that when the zero-value insulator is positioned on the high-voltage side,the electric field's influence on the surface of the insulator string is greater than when it is located in the middle.This influence is also greater than when it is situated on the low-voltage side.Furthermore,the impact of the continuous double-piece zero value on the surface electric field of the insulator string is more significant than that of the non-continuous double-piece zero value,and it surpasses the effect of the single-piece zero value.The interface region between the porcelain and cement at the insulator's steel feet exhibits electric field intensities that exceed the critical threshold of 200 kV/m,making it the optimal area for coating application.A coating width of 10 mm is recommended at this interface. Finally,under normal operating conditions,faint luminescence is observed at the interface of the steel foot coating.When zero-value insulators are present,the grayscale value of the affected coatings decreases to below 30.The severity of the influence follows this order:high-voltage side positioning＞central positioning＞low-voltage side positioning for single defective insulators,with continuous dual defects＞discontinuous dual defects＞single defects.Live-line test results show consistent agreement with surface electric field simulations.In addition,a solution utilizing narrowband optical filtering technology is proposed to effectively mitigate the impact of outdoor ambient light on observational quality.These research outcomes significantly enhance the detection accuracy of zero-value porcelain insulators in transmission lines.