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Compact QEPAS humidity sensor in SF6 buffer gas for high-voltage gas power systems
Xukun Yin1,2, Lei Dong3,4, Hongpeng Wu3,4
1School of Physics and Optoelectronic Engineering, Xidian University, Xi'an 710071, China.
Photoacoustics
|December 22, 2021
Summary
A new sensor detects sub-parts-per-million (ppm) levels of water vapor (H2O) in sulfur hexafluoride (SF6) gas. This advancement enhances safety in high-voltage power systems by preventing corrosion and equipment damage.
Area of Science:
- Electrical Engineering
- Analytical Chemistry
- Environmental Science
Background:
- Sulfur hexafluoride (SF6) is crucial for high-voltage insulation.
- Water vapor (H2O) in SF6 degrades insulation and causes corrosive byproducts.
- Corrosion in power systems leads to equipment failure, leaks, and safety hazards.
Purpose of the Study:
- To develop a sensitive sensor for detecting sub-ppm levels of H2O in SF6.
- To improve safety and reliability in high-voltage gas power systems.
Main Methods:
- Utilized a Quartz-Enhanced Photoacoustic Spectroscopy (QEPAS) sensor.
- Employed a near-infrared distributed feedback (DFB) diode laser for H2O detection.
- Optimized acoustic micro-resonator (AmR) parameters, gas pressures, and modulation depths.
Main Results:
- Achieved a detection limit of 0.49 ppm for H2O with a 1-second averaging time.
- Observed shifts in quartz tuning fork (QTF) resonant frequency and Q-factor due to SF6.
- Determined optimal sensor positioning (1.2 mm from QTF opening).
Conclusions:
- The developed QEPAS sensor system effectively detects low H2O concentrations in SF6.
- This technology offers a powerful tool for proactive safety monitoring in power systems.
- Minimizing H2O impurities enhances the longevity and safety of high-voltage equipment.
