Research On The Influence Of Environmental Factors On Degraded Insulator Heating And Diagnostic Strategy

Porcelain insulators are widely used in electric power system.In actual operation,insulators will deteriorate due to extreme environment,material aging and other reasons,and lose insulation performance.Therefore,the accurate detection of deteriorated insulators is one of the security problems that need to be solved urgently in power system.Infrared thermal imaging technology is widely used in the detection of power system,which has the advantages of simple operation and no contact with live equipment.The temperature rise characteristics of deteriorated insulators are easily affected by the environmental conditio ns and the working conditions of insulators.At present,infrared detection technology diagnoses the deterioration of insulators only by one-sided data and judgment criteria,which has a large workload and a high misjudgment rate.In order to solve these p roblems,this paper studies the heating condition and deterioration characteristics of insulators in different environments,summarizes a more perfect basis for identifying deteriorated insulators,and proposes a new diagnosis strategy combined with time s eries model,which is of great significance for improving the accuracy of infrared detection of insulators.The main work of this paper is as follows: According to the equivalent circuit and temperature rise model of insulator string,combined with simulat ion experiment and theoretical analysis,the voltage distribution model,heating model and temperature rise model of insulator are studied.The influence of environmental temperature on insulator temperature rise is expounded,and the wet pollution model of insulator under different humidity conditions is analyzed.Through a series of simulated experiments in the artificial climate laboratory,the heating law and temperature rise characteristics of deteriorated insulators,the influence of environmental temperature and humidity on the deterioration characteristics of zero-value insulators,and the comparison of the influence degree of environmental factors on the deterioration characteristics are deeply explored.Experiments show that the zero insulator position in the temperature curve of insulator strings will appear negative temperature rise phenomenon,which varies with the deterioration position;the heating and negative temperature rise characteristics of deteriorated insulators are affected by ambient temperature and humidity;the deteriorated insulators have obvious negative temperature rise characteristics at ambient temperature of 25 and humidity of 60%-80%,and the results show that the deteriorated insulators have obvious negative temperature ris e characteristics.The judgment basis for identifying deteriorated insulators under this condition is given.Aiming at the characteristics of impulse noise and Gaussian noise in infrared spectra of insulators,an adaptive median filter method is proposed,which can take into account both denoising effect and image details.The method is used to optimize infrared spectra.At the same time,the insulator steel cap is positioned according to OTSU algorithm and morphological characteristics of insulators,and t he temperature of steel cap is automatically extracted.The improved recognition basis is applied,and a recognition strategy of deteriorated insulators based on time series model and infrared thermal imaging technology is proposed,and the verification ex periment is carried out.The experimental results show that the diagnosis strategy can accurately find the deterioration characteristics of Insulators Based on the establishment of high-precision time series model.