Concentration Measurement Of The Trace Acetylene And Ethane In Transformer Oil

Monitoring concentration of the trace gas dissolved in transformer oil is aneffective method to predict the early inner faults of the transformers. Through earlydiagnosis the potential faults in transforms can keep the electrical equipmentoperation safely and avoid the happening of catastrophic accident. The acetylene(C2H2) and ethane(C2H6) are two important characteristic gas dissolved in transformeroil so detect the concentration of them have great significance in reflecting the typesof fault in transformer. This paper briefly introduces the theory and detection methodsof the mid-IR absorption spectroscopy, the theory of photoacoustic detectiontechnology, the design principle and simulation model of PA cell. This paper mainlyfocuses on theoretical simulation and experiment of photoacoustic (PA) cell designand application. Through comparison of experimental results and the theoreticalsimulation, scheme is put forward to improve the sensitivity of the system.This paper briefly introduced and compared the mid-IR absorptionspectroscopyand photoacoustic spectroscopy technology. Through analysis of thecommon used simulation models, use four-terminal network model to simulate theone-dimensional longitudinal resonant PA cell. This paper also analysis the buffergeometric structure and temperature parameters of photoacoustic features.The finite element software ANSYS and COMSOL are also used to simulate thedumbbell-shaped and π structure of PA cell and obtain correct modeling analysisresults, which lay foundation for analyze of PA cell with irregular shape use finiteelement software.This paper developed photoacoustic experimental system to detect concentrationof C2H2usingDistributed Feedback (DFB) tunable diode laser. This system have goodstabilityand detection sensitivity of1ppm. Through experiment, we analyze thegeometric structure and temperature parameters on photoacoustic features andcompare the experimental results with the theoretical simulation，Average deviation1.1%of geometric structure, and1.3%of temperature parameters.Finally, we developed mid-IR absorption spectroscopy experimental system todetect concentration of C2H6using MIR-LED. This paper explains about the designscheme of optical beam shaping system and the absorption gas cell in detail and put forward an differential measurement scheme to improve the detection sensitivity ofC2H6to70ppm. To further improve the sensitivity, we try to develop thephotoacoustic spectroscopy experimental with MIR-LED. This paper also explainsabout the experimental results and the simulation results of π shaped PA cell, andproved the practical of photoacoustic spectroscopy detection using MIR-LED.