ppb-Level SO₂ Photoacoustic Sensor for SF₆ Decomposition Analysis Utilizing a High-Power UV Laser with a Power...

Area of Science:

• Gas sensing technologies
• Environmental monitoring
• Electrical engineering

Background:

• Sulfur hexafluoride (SF6) is a potent greenhouse gas used in high-voltage electrical equipment.
• Degradation of SF6 can produce harmful byproducts like sulfur dioxide (SO2), indicating equipment malfunction.
• Accurate and sensitive detection of SO2 is crucial for maintaining power system integrity and environmental safety.

Purpose of the Study:

• To develop a highly sensitive photoacoustic gas sensor for detecting sulfur dioxide (SO2).
• To enable the detection of SF6 decomposition products within electric power systems.
• To achieve a low detection limit for SO2 for early fault identification.

Main Methods:

• Utilized a novel 266 nm low-cost, high-power solid-state pulse laser.
• Employed a high Q-factor differential photoacoustic cell for enhanced sensitivity.
• Implemented passive Q-switching technology for the ultraviolet (UV) laser, achieving 28 mW output power.
• Normalized photoacoustic signals to laser power to mitigate fluctuations.
• Optimized sensor parameters including laser power and operating pressure.

Main Results:

• Achieved a 1σ detection limit of 2.34 parts per billion (ppb) for SO2 with a 1-second integration time.
• Obtained a normalized noise equivalent absorption (NNEA) coefficient of 7.62 × 10⁻¹⁰ cm⁻¹WHz⁻¹/².
• Demonstrated the sensor's capability for sensitive SO2 detection relevant to SF6 decomposition.

Conclusions:

• The developed SO2 photoacoustic sensor offers high sensitivity and low detection limits.
• The sensor is suitable for monitoring SF6 decomposition in electric power systems.
• The novel combination of a UV pulse laser and differential photoacoustic cell provides a promising solution for gas analysis.