Features of thermovision control of open substations equipment with wind load registration

Abstract

The features of the thermovision control of open substations electrical equipment when exposed to air flow (wind loads) are considered. Wind loads have a significant impact on the change (decrease) of the surface temperature of electrical equipment, which is confirmed by the experimental data presented. Disregarding wind loads impact reduces the reliability of the results of thermovision tests and subsequent expert evaluation, including hidden defects in the structure. There is no method for assessing the effect of air flow on the surface temperature of the object under study. The lack of a technique is a cause of deterring the use of thermovision diagnostic methods for evaluating electrical equipment. In order to take into account the impact of wind loads, a method developed by the authors for considering the cumulative influence of numerous factors was proposed for estimating the density of heat fluxes in the volume of electrical and dielectric materials during operation. The collection of experimental data was carried out for objects from various materials: porcelain, aluminum, nichrome. The main factors influencing the surface cooling intensity are substantiated: excess of the surface temperature blown by the wind Δtв, external diameter D of the structure, air speed v, medium temperature T0, thermal conductivity coefficients of materials, surface emissivity coefficients, electrical resistance of conductors, and features of the shape of the analyzed node. As a result of the analysis of experimental data, it was found that with an increase in the speed of the air flow up to 5 m/s, the temperature decreases by 25-30 ° C. The sharpest decrease in temperature of the objects under study is observed with an increase in the speed of the air flow from 0 to 1 m/s.