Research On SF₆ Detection System Based On Infrared Imaging

Sulfur hexafluoride gas is widely used in electrical equipment as insulation medium and arc extinguishing medium due to its good insulation characteristics and arc extinguishing characteristics,but often causes gas leakage due to different reasons,which has various effects.Passive infrared imaging is a new type of detection technology that has developed rapidly in recent years.It has the advantages of long detection distance,high efficiency,dynamic and intuitive.However,the infrared radiation emitted by the background will be changed by the leakage gas temperature,concentration,and background temperature during the transmission to the thermal imager,which will affect the detection effect.Aiming at the problem,a gas-equivalent blackbody temperature difference model was established in this paper,and the change trend of the detection effect with the above factors was obtained through simulation analysis of the model.At the same time,a new infrared image dynamic compression and target detail enhancement algorithm is designed to achieve the enhancement of the sulfur hexafluoride gas image with unsatisfactory detection results and improve the imaging quality of the infrared thermal imaging system.To a certain extent,the detection efficiency of inspection personnel is further improved,so that subsequent maintenance can be carried out as soon as possible.The main research contents of the paper are as follows:1)The basic principle of passive infrared imaging for detecting leaked gas is analyzed,and the radiation transmission equations under different paths are derived based on the layer radiation transmission model.The expression of the detector output voltage was deduced to construct the infrared detector response model.2)Based on the infrared detector response model and layer radiation transmission model,a gas equivalent blackbody temperature difference model is established.Through MATLAB simulation analysis,when the gas concentration changes and the gas is at critical and non-critical temperatures,the amount of gas transmitted through the background,The trend of the radiation of the gas itself,the total radiation of the gas path,the difference between the radiation of the gas and the non-gas path,and the temperature difference of the equivalent black body temperature of the gas.3)Based on DDE digital enhancement technology,a new infrared image dynamic compression and target detail enhancement algorithm was established.That is,using a bilateral filter to complete the layering of the image when the leakage concentration is low,and using a linear grayscale mapping and an adaptive enhancement algorithm to process the background layer and the detail layer separately,and linearly fuse the two to obtain an enhanced gas image.By comparing the image simulation results of the new algorithm and the commonly used infrared image dynamic compression and target detail enhancement algorithms,it can be found that the algorithm in this paper enhances the weak gas cloud in the image better than several other commonly used algorithms,which improves to a certain extent the effect of passive infrared imaging in detecting leaked gas is presented.