基于LM算法的CRDS绝缘气体特征分解产物H2S检测技术OA北大核心CSTPCD

With the high sensitivity and fast detection speed of cavity ring-down spectroscopy(CRDS),CRDS has been applied to the field of online detection of H2S of characteristic decomposition components of insulating gases,which is of great significance for the fault state diagnosis of insulated electrical equipment.Ring-down time as the key parameter for concentration calculation,how to fit the ring-down curve to achieve the accurate solution of the ring-down time has become a major difficulty in this technical field.The high-precision fitting algorithm of the decay curve is the key factor determining the accuracy of CRDS.STM32F407 models of single-chip microcomputers are selected to establish the decay curve model,and the Levenberg-Marquardt(LM)algorithm is used to fit and combine the attenuation signals collected by H2S gas at 1578.1nm to build a CRDS experimental platform for verification.Simulations and experiments are conducted based on the LM algorithm,and compared with the least squares method.The simulation results show that the coefficient of determination R2 of the microcontroller fitting reaches 0.996,which is highly close to the offline software platform.The experimental results at different gas concentrations show that the fitting accuracies show an increasing trend.The accurate measurement of trace H2S is achieved by concentration calibration experiment,the correlation coefficient between the actual value of the gas and the measured value is 0.9925,and the absolute errors of the result do not exceed 0.5×10-6.Compared with the concentration measurement results based on the least squares method,the root mean square values of the concentration data based on the LM algorithm are smaller and the detection accuracies are higher.