Conference Paper

Hydrogen Sensor for Oil Transformer Health Monitoring

Appl. Nanotech, Inc., Austin, TX
DOI: 10.1109/NANO.2008.69 Conference: Nanotechnology, 2008. NANO '08. 8th IEEE Conference on
Source: IEEE Xplore


A hydrogen sensor for detection of H2 dissolved in transformer oil has been developed for the use in a stand-alone dissolved gas analyzer (DGA) which will also assess the relative humidity saturation of oil. The sensor uses palladium nanoparticles as a sensitive material that is selective to hydrogen. The DGA will be capable of measuring dissolved hydrogen in concentrations from 50 ppm to 4000 ppm.

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    ABSTRACT: The electrical resistance, R, of an array of 30 palladium nanowires is used to detect the concentration of dissolved hydrogen gas (H(2)) in transformer oil over the temperature range from 21 to 70 °C. The palladium nanowire array (PdNWA), consisting of Pd nanowires ∼100 nm (width), ∼20 nm (height), and 100 μm (length), was prepared using the lithographically patterned nanowire electrodeposition (LPNE) method. The R of the PdNWA increased by up to 8% upon exposure to dissolved H(2) at concentrations above 1.0 ppm and up to 2940 ppm at 21 °C. The measured limit-of-detection for dissolved H(2) was 1.0 ppm at 21 °C and 1.6 ppm at 70 °C. The increase in resistance induced by exposure to H(2) was linear with [H(2)](oil)(1/2) across this concentration range. A PdNWA sensor operating in flowing transformer oil has functioned continuously for 150 days.
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    ABSTRACT: Sensing properties of a chemiresistor gas sensor based on a thin polyaniline (PANI) film are reported. The sensor contains a thin PANI film defined by lift-off on interdigitated micro-electrodes pre-processed on a silicon chip. The sensor sensitivity to hydrogen and ammonia was measured. It was then shortly treated by oxygen plasma, which remarkably enhanced the sensitivity, mainly to hydrogen, and shortened the sensor response and recovery times. The plasma treatment changed the composition, thickness and morphology of the PANI films, which was studied using XPS, FTIR, and AFM. The study necessitated very smooth PANI film surfaces that were achieved by mild sonication of a solution during the chemical polymerization process. The sensor treated by oxygen plasma for 60 s showed a reproducible sensitivity to 10 ppm hydrogen pulses via ∼30% increase in resistance. We believe that this result makes the sensor useful for several room temperature applications.
    No preview · Article · Aug 2012 · Sensors and Actuators B Chemical