Design Of Detector For SF₆Gas Purity And Decomposition

Gas-insulated equipment, which is filled with excellent insulated and dielectric mediumSF6gas, is widely used in the power grid substation equipment for its small footprint. Due topartial discharge and overheating, Gas-insulated equipment may occur electrical fault. If thesepotential failures are not timely detected and treat, it can cause large grid failure. The studyhas found that partial discharge and overheating can appear special gas which is tocharacterize the type and extent of the fault, and therefore detecting internal gas compositionand concentration of insulated equipment is of great significance to regular maintenance andearly failure of analysis equipment.In this paper, the purity and decomposition of SF6analyzer is been designed and thesystem of the gas passages, hardware and software are been given too. The analyzer caneffectively analyze the multi-component gas of gas-insulated equipment, namely it cansimultaneous detect the gas purity of SF6, the concentration of H2S, SO2, CO.This multi-component analyzer detects the gas purity of SF6based on the absorption ofinfrared sensors and detects the concentration of H2S, SO2, CO based on the principle ofelectrochemical sensors. In designing peripheral conditioning circuits of electrochemicalsensor, the nature of the sensor’s weak signal output and noise is been considered. Themicroprocessor STM32is used as the main chip. The LCD touch screen provides a good userinterface, and the scalable external storage device can save important the system informationparameters and large amounts of data the user detection. Considering the electrochemicalsensor’s " poisoning " phenomenon, the design of the gas paths is been optimized in whichestimates and precision measurement modes is been proposed. The design both protects thesafety of the sensor and ensures the accuracy of detection. Real-time embedded systemμC/OS-II is been transplanted to the analyzer and traditional method is abandoned. Themultiple tasks can improve stability and real-time of systems, and is convenient to theongoing maintenance. Different sensors have different calibration methods, the flow sensor using a leastsquares fit and the electrochemical sensors using two-point calibration method for the goodlinearity. The reasons for the error are analyzed and a lot of experiments are been done to findthe error’s rule. Then the temperature compensation, flow compensation, cross-interferenceprocessing algorithms are put forward. With the compensation, the analyzer can achieve highprecision in environmental testing laboratory. In actual field, the analyzer can find the earlyfailure in gas-insulated equipment, resulting in significant social benefits.