电离式三电极碳纳米管乙炔传感器

Triple-Electrode Ionization Acetylene Sensor Based on CNTs

乙炔(C_(2)H_(2))气体是变压器油中溶解的主要故障特征气体之一,乙炔气体检测是实现变压器故障在线监测的关键。现有的乙炔传感器存在灵敏度低、结构复杂等问题。采用微电子机械系统(MEMS)加工工艺设计制作了一种电离式三电极碳纳米管(CNT)乙炔传感器,该传感器工作在非自持放电状态,碳纳米管尖端在低电压下产生高场强,使这种传感器安全运行。实验结果表明该传感器收集极电流随被测气体体积分数的增加而减小,并随引出极电压的增加而增加。该传感器可检测体积分数1×10^(-6)的微量乙炔气体,在室温下工作展现出比同类传感器更高的灵敏度,多次重复性实验标准偏差小于0.042 nA,相对误差小于1.0%;3个不同批次传感器的收集极电流最小偏差为0.9%。传感器表现出了较好的重复性和一致性,在变压器故障检测领域具有应用潜力。

Acetylene(C_(2)H_(2))gas is one of the main fault characteristic gases dissolved in transformer oil.The detection of C_(2)H_(2) gas is the key for the online monitoring of transformer fault.The existing C_(2)H_(2) sensors have some problems such as low sensitivity and complex structure.A triple-electrode ionization C_(2)H_(2) sensor based on carbon nanotubes(CNTs)was designed and fabricated by micro-electromechanical system(MEMS)processing technology.The sensor works at a non-self-sustained discharge state,and the tip of the carbon nanotube generates high field strength at low voltage,which enables the sensor to operate safely.The experimental results show that the collecting current of the sensor decreases with the increase of the measured gas vo-lume fraction and increases with the increase of the voltage applied on the extraction electrode.The sensor can detect the trace C_(2)H_(2) gas with a volume fraction of 1×10^(-6),and shows higher sensitivity than other similar sensors at room temperature.The standard deviation of repeated experiments is less than 0.042 nA,and the relative error is less than 1.0%.The minimum deviation of collecting currents of three different batches of the sensors is 0.9%.The sensor shows good repeatability and consistency,and has application potential in transformer fault detection.