Highly sensitive and selective CO sensor using a 2.33 μm diode laser and wavelength modulation spectroscopy.

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Environmental Monitoring

Background:

• Sulfur hexafluoride (SF₆) is crucial in electric power systems but decomposes into harmful byproducts.
• Monitoring these byproducts, like carbon monoxide (CO), is essential for system health and safety.

Purpose of the Study:

• To develop a highly sensitive CO sensor for SF₆ decomposition analysis.
• To optimize the sensor's performance for real-world power system applications.

Main Methods:

• Utilized 2f wavelength modulation spectroscopy (2f-WMS) with a diode laser at 2.33 μm.
• Employed a 14.5-m multipass gas cell (MGC) for enhanced optical path length.
• Applied a Levenberg-Marquardt nonlinear least-squares fit algorithm for data analysis.

Main Results:

• Achieved a minimum detection sensitivity of 1 ppm for CO.
• Demonstrated a measurement precision of approximately 40 ppb with a 0.6 s update rate.
• Optimized operating conditions yielded a precision of 6 ppb with a 48 s averaging time.

Conclusions:

• The developed 2f-WMS CO sensor is effective for SF₆ decomposition analysis.
• The sensor exhibits high sensitivity, precision, and stability suitable for power system monitoring.
• Optimized gas flow rate and averaging time enhance sensor performance significantly.