Investigating the Output Response of the Relative Saturation (RS) Sensor for Measuring the Moisture in Transformer Oil

This paper proposes the RS sensor
fabricated using inexpensive materials to evaluate its
output voltage corresponding to the moisture. The main
structure of the RS sensor consists of upper and lower
electrodes. The lower electrodes are made of ceramic
and copper, while the upper electrodes are made of
different materials: (1) porous aluminum adhesive
electrode (2) 18650 battery gasket. Furthermore, the
thin-film polymer is placed between the upper and
lower electrodes for sensing the moisture in oil. The
moisture sensing film is highly hydrophilic and is made
of silicone film. For measuring the output voltage of the
RS sensor, a voltage sensor is connected to Arduino
Uno. The test condition is categorized into 4 ranges of
the oil temperatures: (1) at 10-14 °C, (2) at 30-35 °C, (3)
at 60-65 °C, and (4) at 80-85 °C. The results show that
the value of the output voltage of the sensors vary
directly to the value of moisture in ppm and the
temperature of the oil. To integrate the effects of both
factors, the output voltage of each sensor is plotted as a
function of the %relative saturation(RS). The output
voltage of the sensors decreases as the %RS increases.
However, with R-squared (R2) value of each graph
shows that the relationship of the output voltage as a
function of %RS is a good linear for all three sensors.
Then, this leads to a good indication to use the RS
sensor for continuous moisture measurement in
transformer oil.