Simultaneous Detection of Hydrogen and Acetylene Using a Photoacoustic Gas Sensor Based on Frequency Tracking and...

Area of Science:

• Electrical Engineering
• Analytical Chemistry
• Spectroscopy

Background:

• High-voltage electrical equipment insulation degrades during faults, releasing gases like hydrogen (H2) and acetylene (C2H2).
• Existing gas detection methods face challenges with cross-sensitivity, size, and reliability, hindering effective monitoring.

Purpose of the Study:

• To develop a compact and reliable photoacoustic spectroscopy (PAS) gas sensor for simultaneous H2 and C2H2 detection.
• To utilize acetylene (C2H2) as both a target gas and a pump gas to enhance H2 detection sensitivity.

Main Methods:

• A single distributed feedback (DFB) laser-based PAS sensor was employed for gas detection.
• Gas detection involved tracking frequency shifts due to sound velocity changes and analyzing harmonic components from infrared absorption.
• A calibration model was developed by studying H2's attenuation effect on photoacoustic signals to correlate C2H2 concentration with harmonic peaks.

Main Results:

• The system achieved minimum detection limits (MDLs) of 96 ppm for H2 (5.6 s integration) and 0.73 ppb for C2H2 (894 s integration).
• The developed calibration model accurately correlated C2H2 concentration with harmonic peaks under varying H2 concentrations.
• Allan deviation analysis confirmed the system's stability and detection capabilities.

Conclusions:

• The proposed PAS sensor enables integrated gas analysis in hydrogen-rich environments, overcoming limitations of current methods.
• This technology shows significant potential for in situ monitoring and early fault detection in power systems.