On-line detection of fault characteristic gases released by the insulation oil of transformers is developed as a scientific basis for estimating explosion accidents. However, the performance of most gas sensors, such as H ₂ and C ₂ H ₂ sensors, is usually affected by temperature, and there exists large detection error when the temperature of transformer oil changes in operation. And the existing temperature compensation methods suffer from problems such as low integration, large volume, and high costs. Herein, a sensor array based on three triple-electrode sensors with carbon nanotubes was fabricated. Each of the three sensors has three vertically stacked electrodes with various interelectrode distances. The first and second sensors were used to detect H ₂ and C ₂ H ₂ , respectively, and the third sensor was used to measure temperature. All the detection mechanisms are based on the dependence of discharge current on gas concentration and temperature. The sensor array could detect H ₂ /C ₂ H ₂ mixture and temperature due to the exponential function between the output currents and electrode separations. The proposed sensor exhibited low relative and repeatability error values less than 5.1% and 4.9%, respectively, and displayed humidity compensation potential like temperature. High integration makes the sensor array superior among the other mechanism sensors.

The three kinds of gases such as NO 2 , NO, and SO 2 produced by industrial combustion process are the main sources of atmospheric pollution. Almost all the available technologies of measuring three components in mixed gases are limited by detection range, operating temperature, and integration, etc. Here we report an array with three triple-electrode carbon nanotube sensors and its sensitivity to the three flue gas components. The three sensors operate at the same gas ionization mechanism and are comprised of a common long cathode, three extracting electrodes and three collecting electrodes, and are set by different electrode separations with $75\ \boldsymbol{\mu} \mathbf{m}, 100\ \boldsymbol{\mu} \mathbf{m}$ , and $120\ \boldsymbol{\mu} \mathbf{m}$ , respectively. We explored and obtained distinct single-valued sensitive characteristics to the three-component gases at given voltages applied on electrodes, which should be higher than a critical voltage to obtain single-valued sensitivities of the three sensors. The standard deviation of repeatability experiment is less than 0.133 nA, which indicates that the sensor has a good repeatability. The array displays a high level of integration and small size, and also has the potential to detect the concentrations of different components of gas mixtures.